MUS 3313 Terms & Concepts Glossary

(Terms from class discussions & handouts will be added throughout the semester.)

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3DMF
A cross application and cross platform standard for three dimensional imaging proposed by Apple.
1/4 " plug
Secondary name for a phone plug. Type of connector common in musical instrument hookups and consumer level microphones. So named because it was invented by Bell Telephone for its operators. Phone plugs also come in 1/8 inch, and some smaller sizes.
10
The number of bits in a full MIDI bit set. This includes the start bit, the MIDI byte (which conveys the meaningful code), and the stop bit.
10010000
Typical method for coding a digital 8 bit byte. In MIDI, this byte denotes a note-on command on channel 0.
1128
Speed of sound in air at 68 degrees Farenheit.
120
A commonly referenced point on the decibel scale at which sound intensity begins to cause pain in humans.
16 bit sampling
Denotes a degree of resolution in any single measurement when representing analog phenomena with digital data. 16 bit sampling allows for any integer between 0 and 65536 which, in audio, would be considered highly accurate-- so called CD-quality.
16384
In MIDI this represents the number of unique combinations possible using two byte. Normally two 8 bit bytes would yield 65536 unique combinations-- 2 to the 8th power (256) times 2 to the 8th power. However, in MIDI, the most significant bit of a byte is always used to signify whether the byte is to be interpreted as
16x4x2
A common method for representing an audio mixer's channel routing capabilities. The first number shows the number of inputs, the middle shows the number of auxilliary busses, and the last shows the number of main outputs.
2097152
In MIDI this represents the number of unique combinations possible with 3 bytes.
24
The number of MIDI clocks in a quarter note. MIDI sequencers can usually be set to transmit or receive MIDI clock commands. Each of these one byte, real-time system messages steps the receiving sequencer ahead by one 24th of a quarter note. Why 24 per quarter note? Because that number allows representation of all normal beat subdivisions: 18 clocks = dotted eighth, 16 = triplet quarter note, 12 = eighth, etc... down to 2 = triplet 32nd.
256
The number of combinations that can be derived from a single eight bit byte (2x2x2x2x2x2x2x2=256).
31250
MIDI's communication speed in bits per second.
5 milliamp
The electrical current flow that a MIDI device senses as "ON."
601
First of the new generation of Motorola RISC processors. Released in 1993. With proper programming, it provides processing power equal to an Intel Pentium at about half the price and with less power consumption. The 601 superscalar architecture features 3 pipelines making it possible to execute 3 instructions at once.
604
Newer model of the Motorola line of RISC processors. Released in 1994, this model features higher clock rates, a larger cache, and new superscalar design. Used in high end Macintoshes. The 604 superscalar architecture features 6 pipelines allowing up to 6 instructions to be executed at once.
640 x 480
Most common size for current computer monitors. The numbers represent 640 pixels across the visible area of a monitor by 480 scan lines from top to bottom
680x0
Numbering system for Motorola's popular family of 32 bit CISC processors: 68000, 68010, 68020, 68030, 68040, 68060. They were used in Macintoshes, Amigas, Ataris, and a variety of workstations.
8 bit sampling
Denotes the sampler's resolution ability in any single measurement. An 8 bit sampler provides 256 levels when measuring an analog phenomenon like a sound wave. This yields a rather low quality,
80x86
Numbering system for Intel's very popular line of CISC microprocessors found in about 80% of consumer PC's. They range from the 16 bit 8086 and 80286 CPU's to the current 32 bit Pentium (actually an 80586).

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About
The first menu item under the Apple Menu (left corner of the Macintosh menu strip). When the desktop is active, the About menu dialog box supplies information about the operating system version and memory usage by all software currently loaded into RAM. When an application is running, the same menu item provides copyright information about the program and may provide other info as well.
Absolute time
Temporal measurement in hours, minutes, seconds, and frames. This is opposed to relative time in which the measurement is made in variable units like metronomic beats.
Absorption
In acoustics, the quality of a material that prevents sound transmission or reflection. Absorption trnsforms mechanical energy (sound) into heat.
AC
Acronym for Alternating Current. The electricity that comes from a typical wall socket to an electrical device. It flips between negative to positive charge 60 times per second and has a normal pressure of 110 to 120 volts.
Acoustic
Relating to any device that produces sound by mechanical rather than electronic means.
Active
In the Macintosh, a screen image (icon, verbal command, window, etc.) or a program that has been selected and is ready for interaction with the user.
Active matrix display
A liquid crystal display panel technology that used a separate transister for each pixel on the screen. It reacts faster and so gives better video quality than older passive matrix technology.
Active sensing
An optional MIDI message that allows a device to detect connection problems.
ADB port
Acronym for Apple Desktop Bus. The IO line used on a Macintosh to connect most human input devices like the keyboard, mouse, joystick, graphics tablet, etc. The single line can connect up to 16 devices in series (hence the name bus). Communication is serial, asynchronous at a maximum speed of 4,500 bits per second.
ADC or A/D converter
Asymmetrical for Analog to Digital Converter. A circuit that takes periodic measurements of an analog waveform.
Additive synthesis
A form of tonal synthesis based on combining many single frequency waveforms to construct a complex tone. It relies on the Fourier principle: that all complex waves are merely collections of single frequencies at varying amplitudes. While it is an easy technology to understand, the fact that it requires realtime control of 10 or more oscillators for each note created, it is rather expensive to implement and control.
Address
A number associated with a physical location in memory. Every one of the millions of on/off circuits that make up RAM has a unique address which allows the central processor to store and retrieve data intelligibly.
Address
In internet communication, the location of a computer, file, or other object on a network (as in IP address, Web address, etc.)
Address bus
The copper traces on a motherboard that lead from the central processor to RAM through which flow the locations of data bits. The data bits themselves travel a separate path known as the data bus.
ADPCM:
Adaptive delta pulse code modulation. An audio compression algorithm for digital audio based on describing level differences between adjacent samples.
ADSL
Acronym for Asynchronous Digital Subscriber Line. A communications technology that could allow rapid transmission of digital data over existing telephone lines. Speed varies from 640 Kbs to 1.544 Mbs compared to current modem limitations of 56 Kbs.
ADSR:
Attack/decay/sustain/release, the four segments of a common type of synthesizer envelope. The controls for these four parameters determine the duration (or in the case of sustain, the height) of the segments of the envelope. See envelope.
AES/EBU null clock
The word clock data imbeddedin an AES/EBU audio signal. All AES/EBU digital audio signals carry word clock data, but if only this clock informationis passed father than any actual digital audio, the signal isknown as "null clock."
Aftertouch:
A type of control data generated by pressing down on one or more keys on a synthesizer keyboard after they have reached and are resting on the keybed. See channel pressure, poly pressure.
AIFF
Audio interchange file format. A common Macintosh audio file format. It can be mono or stereo, at sampling rates up to 48kHz. AIFF files are QuickTime compatible.
Algorithm
A set of mathematical and logical instructions used by a computer program to carry out a task.
Algorithmic composer
A computer program used for music creation in which the large outlines of the piece, or the procedures to be used in generating it, are determined by the human composer while some of the details, such as notes or rhythms, are created by a computer program using algorithmic processes.
Alias
In the Macintosh operating system, an alias is a replica of an icon which carries the same functions as the original but takes up almost no disk space. It is basically a pointer to the original item and is useful because it allows the item to be accessed from multiple points within the file system.
Alias
Undesired frequencies that are produced when harmonic components within the audio signal being sampled by a digital recording device or generated within a digital sound source lie above the Nyquist frequency. Aliasing differs from some other types of noise in that its pitch changes radically when the pitch of the intended sound changes.
All-notes-off
A MIDI command, recognized by some but not all synthesizers and sound modules, that causes any notes that are currently sounding to be shut off. The panic button on a synth or sequencer usually transmits all-notes-off messages on all 16 MIDI channels.
ALU
Portion of a microprocessor's circuitry that carries out calculations and data comparisons. In an oversimplified explanation of a microprocessor's operation, digital data are requested from various addresses in RAM, logically processed in the ALU, and then sent out to other addresses in RAM.
Ambiance
The combination of reverberation qualities that hint at the physical characteristics of the sound source's environment.
Ampere
A unit used to measure how much current is flowing in a circuit.
Amplifier
A device that increases the power level of an electrical signal. This can occur in several stages: a pre-amplifier is used to raise a low-level signal like a microphone or a phonograph cartridge up to "line" level at which point a power amplifier raises it again to a level appropriate to drive speakers. The amplifier must raise this signal without adding appreciable electronic noise or distortion.
Amplitude
One of four objective or measurable attributes of sound, it represents the amount of energy in a signal. Amplitude is measured by determining the departure from normal in air pressure (of a sound), voltage (of an electrical signal), or numerical data (in a digital application). When the signal is in the audio range, amplitude is perceived as loudness.
Analog
A representation of an object or phenomenon in a manner that resembles the original in its continuous , infinitely divisible form. For example a phonograph record's groove is basically a continuous picture of the original sound wave. Contrast this to digital representation which measures an object or phenomenon at regular intervals and stores these measurements as discrete numbers for later building a useable representation of the original. Compare with digital.
And
One of the fundamental comparisons used in Boolean logic. The AND comparison results in 'true' only if both inbuts are true. In binary math all mathematical operations can be reduced to these fundamental comparisons. This makes it possible for combinations of mechanical or electrical circuits called logic gates to carry out complex calculations.
Anechoic
Disabling sound reflection. It usually refers to a chamber or room lined with sound absorbing materials placed in patterns that further reduce reflection. Since sound waves in the audible spectrum vary in length from less than an inch to over fifty feet, anechoic rooms must be large and of complex design to stop all echoes.
Anonymous FTP
A type of File Transfer Protocol that lets you connect to a network, access directories, and obtain files without having to enter a username or password.
ANSI
Acronym for American National Standards Institute. An organization that oversees the adoption of many technology standards in the U.S. A NSI is a member of the International Standards Organization.
AOL
Acronym for America OnLine. The world's largest commercial online service, AOL offers its members many information services-- email, chat, news, special interest groups and data bases in addition to connection to the Internet.
Aperiodic motion
Vibration that has no regularity-- that occurs randomly. In sound, aperiodic motion causes noise; periodic motion causes tone.
API
Acronym for Application Program Interface. A low level messaging format that allows programs to communicate with each other and work together.
Apple menu
The leftmost item on any Macintosh program's menu strip. It provides access to many utilities such as the Chooser (for selecting printer drivers and Appletalk network connections) and Control Panels (for manipulating various interface controls).
Applet
A small computer program written in the Java computer language. It can be added to a web page, and a browser can execute and display it.
Application
Computer software designed to do a specific task for the end user and output a document of some kind. Examples: word processor, sequencer, note editor.
Application icon
A small image on a graphic user interface (Macintosh & Windows) that launches a computer program when double-clicked.
Application menu
The rightmost item on a Macintosh menu strip. It represents the currently running program and gives access to any other program loaded into RAM.
Arithmetic scale
A set of numbers that relate to each other in simple additive progression as opposed to a logarithmic scale in which the numbers relate as multiples. In an common arithmetic scale, the number 20 is ten units more than the number 10 and the number 30 is twenty units more than 10. In a logarithmic scale like that applied to sound amplitude (decibels) the number 20 represents ten times the value of the number 10 and the number 30 represents 10 times the number 20 and therefore 100 times the value of the number 10.
Archie
A program used to search files at FTP sites; there are approximately 30 Archie servers in the world.
ARPANET
The precursor of the Internet. Arpanet (Advanced Research Projects Agency Network) was created in 1969 to connect computers at military instalations and research agencies. It pioneered packet switching technology as a means to convey digital data safely over any momentarily available physical channel.
ASCII
Acronym for American Standard Code for Information Interchange. ASCII is a universal standard for transmitting alphanumeric characters, decimal numbers, punctuation symbols, and printing commands among nearly all computers throughout the world. It uses 7 bits of a byte to convey 128 common symbols and the 8th bit to convey more unusual symbols and graphics depending on the particular computer.
ASIC
Acronym for Application Specific Integrated Circuit. A chip constructed for a specific purpose rather than for use in a wide variety of products. The Ensoniq Mirage was one of the first electronic musical instruments to make use of ASICs and, as a result, was much less expensive to produce.
Asynchronous
An electronic data transmission method that does not rely on regularly timed intervals or handshaking. It requires that each byte of data transmitted be prefixed with a start bit and suffixed with a stop bit to signal the receiving machine that it should interpret the enclosed pulses as a unit.
ATMI
Acronym for the Association for Technology in Music Instruction. An organization of music teachers dedicated to promoting the use of computer and electronic music technology in music education. ATMI publishes a comprehensive, near-yearly updated guide to music related software and some hardware products.
Attack
The first part of the sound of a note. In a synthesizer envelope, the attack segment is the segment during which the envelope rises from its initial value (usually zero) to the attack level (often the maximum level for the envelope) at a rate determined by the attack time parameter.
Attenuate
To reduce the level of a signal.
Attenuator
A potentiometer (pot) that is used to lower the amplitude of the signal passing through it. The amplitude can usually be set to any value between full (no attenuation) and zero (infinite attenuation). Pots can be either rotary or linear (sliders), and can be either hardware or "virtual sliders" on a computer screen.
.AU
An audio file format common on Unix based platforms and on the Internet
Audio chain
The arrangement of components that transfers a sound from source to ultimate destination. For example; 1) microphone, 2) pre-amplifier, 3) sound processors, 4) power amplifier, speakers.
Audio ports
The physical connection points on a computer or sound card through which a sound signal can be either sent out or received in. The out port is normally designed to output a line level signal. The in port is also usually line level also but can be mic level. On a Macintosh, the mic in port is actually a line level port and requires a special Apple microphone or a preamped (line level) signal.
Auditory canal
The tube-shaped opening connecting the outer ear (pinna) and the eardrum. The term meatus also refers to the auditory canal.
Auxilliary input
A secondary receiver that routes a signal directly to the bus of a mixer.

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Background printing
The ability of a computer to print a document while allowing the user to begin working on another project. The Macintosh uses this feature.
Backup
To make a duplicate of a file for safety in case the original is destroyed.
Baffle
The front panel of a speaker cabinet on which the speaker is mounted. It prevents reversed waves from the back side of the moving speaker cone from interfering with the frontal waves.
Balanced line
A three wire audio connection cable in which one wire serves as the ground and the other two carry the signal in mirrored polarity. When one of these polarities is reversed at the receiving device, it effectively mirrors and cancels out any induced line noise.
Band
Any contiguous portion of an anergy spectrum or range of frequencies.
Band pass filter
A circuit designed to transfer a narrow range of frequencies while reducing the power of frequencies on either side.
Bandwidth
The available "opening" through which information can pass. In audio, the bandwidth of a device is the portion of the frequency spectrum that it can handle without significant degradation. In digital communications, the bandwidth is the amount of data that can be transmitted in a given period of time.
Basilar membrane
The portion of the inner ear or cochlea that vibrates sympathetically with waves of mechanical energy transmitted from the outside environment. Different frequencies resonate different regions of the basilar membrane. Hair cells on the organ of Corti lying alongside the membrane convert this physical stimulation into nerve impulses which the brain interprets as sound.
Baud
The number of voltage changes per second. Named after French mathematician Jacque Baudot, this term is often used to refer to the number of bits a digital source produces per second. However, it is not a linear relationship. It is more accurate to use bps (bits per second).
BBS
Acronym for Bulletin Board Service. A computer used as a dial up service on which callers can upload or download both messages and binary files. Callers can also use BBS's to exchange text messages in real time.
Beating
Audible interference caused by two closely related frequencies sounding together. A-440 and A-444 played at the same time would cause a 4 cycle per second beat.
Benchmark
A standardized test result against which other tests are measured. Benchmarks are useful in rating computer performance in understandable terms.
Bernoulli
Generic term for a type of high-capacity data storage technology that uses a removable cartridge and doesn't lose data when power is removed from it.
Biamp
Dividing the audio range in two so that the low and high frequencies can be amplified by separate electronics specially designed for their spectra.
Binary
Having only two options. A counting system composed of only two digits, 0 and 1. In order to show numbers larger than 1 in the binary system, multi-digit numbers are created in which each place represents 2 times the place to its right. For example the binary number 11111111 equals 128 + 64 + 32 + 16 + 8 + 4 + 2 + 1 or 255. Although binary enumeration seems clumsy to most humans, it is ideal for computers and most other digital devices which at their most basic level simply turn circuits on and off at incredible speeds.
Binary file
A numeric representation of a computer program, image, sound, etc. It is not easily human readable. Compare to an ASCII (text) file in which numbers represent codes for alpha-numeric characters. Computers must first recognize the difference between the two basic formats before they can use or display the encoded information correctly. If you've ever seen unrecognizable character "garbage" displayed on your monitor, you are probably looking at a binary file interpreted as text.
BinHex
A file conversion standard used for sending executable programs from site to site using ASCII codes. At the receiving end, BinHexed files must be un-encoded with a decompression program like Stuffit to be useable.
BIOS
Acronym for Basic Input/Output System. The ROM-based operating system software that controls a computer's communication with peripheral devices like the keyboard and mouse.
Bi-phase
An electronic reference signal used by filmmag recorders, editing stations, and projectors.
Bit
Short for Binary digIT. The smallest unit of data a computer can handle. Each bit has a value of 0 or 1 that the computer interprets as "off" or "on" respectively.
Bitmap
An organized matrix of many small dots that when seen together yeilds an image. Pictures in magizines, alpha-numeric characters created by a laser printer, and a computer's video monitor are all examples of bit maps.
Bit resolution
The number of bits used to make any single measurement in a sampling circuit. The more bits used, the better the signal to noise ratio of the device. 16 bit resolution is considered "CD quality" as it produces a relatively wide 96 dB signal to noise ratio.
blackburst
A type of clock reference. It is essentially a video signal without any picture and without any positional information.
BNC
A type of connector used in electronic devices distinguished by a locking ring that secures the cable to the socket when turned. BNC stands for British Naval Connector. It is common in high end scientific and video devices but is recently becoming more common for digital audio as well.
Bomb
A program or system malfunction that causes a computer to cease operating, to "freeze." In the Mac, this is often accompanied by a dialog box with a bomb icon in it and a brief numerical description of the error.
Boost
Informal term for increasing the gain of frequency band.
Bookmark
A stored reference to a recently accessed web page. Bookmarks are useful in Internet browsers because they substitute easily identifiable names for often long and vague URL addresses. Most browsers allow the user to bookmark a web page with a simple key combination or menu selection.
Boolean Logic
A set of rules developed in the 19th century by English mathematician, George Boole. These rules reduce mathematical operations like addition and subtraction to simple comparisons: AND, OR, and NOT. Boolean logic is the fundamental principle which allows digital divices like computers to make decisions and even appear to think.
Boot
To start up a computer. There are various levels of this: A warm boot can usually be executed with a key combination if the machine freezes or just to clear fragmented memory (Command-Control -PowerKey on the Macintosh). For severe crashes a cold boot is done by turning the computer's power off, waiting a few seconds, and turning it back on.
bps
Bits Per Second. Refers to the speed at which a communication technology can transmit data. Divide the bits per second by 10 to get an approximate idea of how many characters per second the modem is transmitting.
Breath controller
A human interface device that translates breath pressure into MIDI aftertouch, conjtrol change, or volume data. They allow a musician to give added nuance to MIDI controlled performance.
Brick-wall filter:
A lowpass filter at the input of an analog-to-digital converter, used to prevent frequencies above the Nyquist limit from being encoded by the converter. See Nyquist frequency, aliasing.
Bridge
A connection between two local-area networks (LANs) that lets data travel from one LAN to another. In audio, to run a stereo power amp as a double powerful mono amp by switching one channel to the positive line and the other to the negative line of the signal.
Browser
A computer program that allows the user to work with the World Wide Web. Currently the most popular browsers are Netscape's Navigator, Microsoft's Internet Explorer and various versions of the earlier Mosaic.
BTW
Email shorthand for "By The Way."
Buffer
An area of memory, used for recording or editing data before it is stored in a more permanent form.
Bus
An electrical connection (wires or printed circuit traces) that is shared by multiple devices. Signals sent on a bus are sensed by all devices but are not necessarily acted upon by all. Computer motherboards contain busses to link the central processor with ROM, RAM, and co-processors. A MIDI daisy chain configuration is actually a bus.
Byte
Eight bits considered as a unit. The various combinations of eight 1's or 0's allow 256 unique codes from 00000000 to 11111111. (MIDI bytes consist of ten bits because each byte includes a start bit and a stop bit, with eight bits in the middle to convey information.)

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Cache
A memory area usually inside a CPU that stores often used instructions. These instructions are accessed much faster than if they were loaded from RAM
Cache
A portion of a hard drive which stores copies of web pages accessed through a browser. The purpose of this cache is to accellerate the apparent download speed when the same page is accessed again. Items in the cache are usually erased automatically after a preset number of days, but they can be "flushed" manually by the user to ensure that the browser is not substituting a local file for an updated web page.
Capacitor
An electronic component whose function is to pass alternating current but not direct current. It is composed of two parallel strips of metal insulated from each other . A charge fluctuation in one strip induces a reverse charge in the other.
Cardioid
A microphone pickup pattern that exhibits more sensitivity at the front than from the back.
Carrier
In FM synthesis, the signal that is being modulated by some other signal.
CD ROM
Acronym for Compact Disc Read Only Memory. A standard storage medium for large amounts of computer data. Externally it is identical to an audio CD; however the data is encoded differently. In its original form It has the capacity to permanently store more than 600 million bytes of data; however new technologies like DVD are about to make possible much larger storage capacities (up to 16 gigabytes).
Cent
The smallest conventional unit of pitch deviation. One hundred cents equal one half-step.
Center detent
The position to which a control knob or wheel tries to return when not under direct human control. It represents the normal level for whatever variable the wheel is assigned to. For example in a pitch wheel the center detent represents perfect tuning.
CGI
Acronym for Common Gateway Interface. A standardized method of passing data received by a web server to various programs which process the information and return a result. It is a common way of allowing a client machine to pass information to the server machine rather than merely requesting data from it as is its normal function.
Channel
An electrical signal path. In analog audio (such as a mixer), each channel consists of separate wired components. In the digital domain, channels may share wiring, and are kept separate through logical operations. MIDI provides definitions for 16 channels, which transmit not audio signals but digital control signals for triggering synthesizers and other devices.
Channel aftertouch
A type of MIDI data generated by pressing down on one or more keys on a synthesizer keyboard after they have reached and are resting on the keybed. Distinguished from key, or polyphonic, aftertouch, channel aftertouch affects all notes currently being played on the same channel when any one note receives the message.
Channel message
Any type of MIDI data disigned to be acted upon only by devices set to the the data's embedded channel number. There are seven channel messages defined by the MIDI specification: Note Off, Note On, Poly Key Pressure, Control Change, Program Change, Channel Pressure, and Pitch Bend. Compare channel messages with system messages, i.e. those designed to be received by any connected instrument no matter what channel it is set to.
Channel pressure
A type of MIDI control message that is applied equally to all of the notes on a given channel; the opposite of poly pressure, in which each MIDI note has its own pressure value. Also called aftertouch, channel pressure is generated on keyboard instruments by pressing down on a key or keys while holding them down. See aftertouch, poly pressure.
Chip
An informal term for the physical packaging of an integrated circuit. It is usually a small square or rectangle of protective ceramic encasing the still smaller silicon wafer that holds the actual circuitry. Wires or metal tabs protrude from the sides or bottom of the chip in various configurations.
Chooser
In the Macintosh interface, a panel which allows the user to select a device driver (usually for a printer) or a specific Appletalk network connection.
Chorus
A type of audio signal processing. A replica of the sound is time-delayed and slightly detuned and then is remixed with the original signal. The mixing process changes the relative strengths and phase relationships of the overtones creating a thicker sound imitating the sound of several simultaneous sources. The simplest way to achieve chorusing is to detune one synthesizer oscillator from another to produce a slow beating between them.
Circuit switching
A communication method that keeps a channel between transmitter and receiver open at all times whether or not data is being exchanged. A telephone call is a good example because the electronic connection between two parties is active even at times when neither person is talking.
CISC
Acronym that stands for Complex Instruction Set Computer. As opposed to RISC processors, CISC cpu's use a larger number of internal instructions to complete a processing task.
CLI
Acronym for Command Line Interface. A system of communicating with a computer that relies on words rather than images. The user types in acronyms to direct the computer to do certain tasks, and the computer responds with words on the screen. MS-DOS was a popular form of CLI.
Client
A computer whose function is primarily to receive data from a server and display it for the user.
Click
In a Mac or Windows interface, the act of setting the mouse pointer over a screen icon or other visual interface image and depressing the mouse button. Single clicking usually selects the icon/image for further action.
Click & drag
In a Mac or Windows interface, the act of setting the mouse pointer over a screen icon or other visual interface image, holding the mouse button down, and pulling/pushing the mouse. This action usually drags the icon/image with the mouse pointer.
Clip Art
Computerized image collections that users can copy and use in their own documents.
Clipping
Distortion caused by feeding a signal greater than the circuit's capacity. It "clips" or squares off any part of the signal greater than the electronics can handle.
Clock
In MIDI, a system real time message that advances a receiving sequencer ahead by 1/24th of a quarter note. In computers, a timing device whose purpose is to regulate internal tasks so that they occur in an organized fashion.
Clock crystal
A timing device whose purpose is to regulate internal computer tasks so that they occur in an organized fashion.
Closed architecture
A computer whose system specifications are not made public. This practice keeps development of expansion products under the control of the computer manufacturer but severly limits the machine's long term viability.
Close box
Square, marked area at the upper left corner of a window in the Macintosh interface which, when clicked, closes the window.
Cochlea
The snail shell shaped inner ear in which the physical energy of vibration is transformed into electrochemical nerve impulses that the brain interprets as sound. Important parts of the cochlea include the oval window, which receives vibrations transmitted from the eardrum, the basilar membrane which vibrates in different regions in response to different frequencies, and the adjacent organ of Corti, in which hair-like cilia excited by the basilar membrane's vibration produce the electrochemical stimulus.
Code
The numerical instructions written by a programmer which cause a computer to carry out intended operations.
Codec
Acronym for Compressor-Decompressorr. An electronic device that makes digital signals (sometimes converted from analog signals) smaller prior to sending them over a line. The same device at the other end of the line converts them back to their original configuration.
Combination tones
Perceived tones whose frequencies result from the difference and sum of two other frequencies sounded together. Thus when a tone with a frequency of 800 cps and a tone with a frequency of 500 cps are played together, the listener often hears other tones at 300 cps and 1300 cps although these frequencies are not physically present in the sound sources.
Command
A word, string of words, or series of characters that cause the computer to carry out a specific action. In Windows and Macintosh, GUI interfaces nearly all commands are a part of a menu and are selected with a mouse. In a CLI shell, the commands must be typed.
Command key
In a Macintosh computer, the command key in combination with other keys carries out actions duplicating those chosen from the menu strip. It is often more convenient to use a command key combination than to choose a menu command using the mouse.
Companding
A type of signal processing in which the signal is compressed on input and expanded back to its original form on output. Digital companding allows a device to achieve a greater apparent dynamic range with fewer bits per sample.
Composite video
A video signal that mixes red, green, and blue components together. Most televisions use composite video, but computer monitors usually need higher resolution ans so use separate lines for the primary colors
Compression
Any method of making computer data smaller so fewer data are needed to represent the same information so the information takes up less disk or file space and may be transmitted in less time.
Compression
Higher than normal density of air molecules found in a sound wave. In sound ,compression is always followed by equivalent rarefaction so that the average pressure remains the same. The variance of pressure in compression and rarefaction in sound is quite small-- approximately 1 ten-thousandth of a percent departure from normal for sound at 60 dB (the amplitude of normal conversation).
Compression
The process of reducing the amplitude range of an audio signal by reducing the peaks relative tp the low levels.
Compressor
An audio component that reduces the power of a signal proportionally when it rises above a certain setting. This as opposed to a "limiter" which simply will not allow passage of signal powers above the set limit but has no effect on powers beneath it
Compressor/Limiter
A sound processing device whose function is to keep amplitude peaks below a level that would cause distortion. When compression is applied, the higher amplitudes are reduced more than lower amplitudes on an adjustable scale. When the limiter is applied, amplitudes above a chosen level are prohibited but amplitudes below this level are not affected.
Condensor microphone
A sound to electricity transducer that operates on the principal that as an electrically charged diaphragm vibrates close to an oppositely charged plate, current flow is produced. Condensor microphones usually require a source of electricity to create the charge. This can come either from batteries or from "phantom power," a DC voltage supplied from the connected device through the microphone cable.
Conductor
Any material that can carry an electric current. Metals like copper, silver, and gold and aluminum are the most common.
Continue
In a sequencer, the command to begin playing at the point where the sequence was paused. The MIDI command of the same name has the same function.
Continuous controller
A type of MIDI channel message that allows control changes to be made in notes that are currently sounding.
Continuous power
A power rating applied to audio amplifiers. It represents the amp's power delivery capability when working under a constant signal like a 1000 cycle per second tone. It is also known as RMS power.
Control change
One of seven basic channel messages outlined in the MIDI specification. It is somewhat different from the other six because it is actually a command to open a subset of secondary performance command codes. These include volume, pan, portamento, sustain, and many as yet undefined. The last six control change codes (122 - 127) represent mode controllers which dictate how the receiving instrument should respond to incoming data.
Control key
On a Windows PC this key is equivalent to the Command key of a Macintosh. On a Macintosh, the control key provides added commands.
Control panel
On a Macintosh, control panels allow the user to change many parameters of the interface. Found under the Apple menu, these controls include Monitors, Sound, Speech, File Sharing, General Appearance, and many others.
Control strip
A tab that appears on the Macintosh screen. It allows quick access to common control panels.
Coprocessor
An integrated circuit that takes over one or more of the functions usually done by the central processor. Because it is built for a specific purpose, it can usually execute these functions more efficiently than the CPU. Common coprocessor functuions have included math, graphics, sound, memory management, and peripheral handling.
Copy protection
Any method used to foil unauthorized duplication of software. The most effective is the hardware key, or dongle, that must be attached to one of the computer's ports in order for the software to function. Most commercial software titles require only that a serial number be entered when the program is first used. While not foolproof, this system does make illeagal copying more difficult.
CPS
Acronym for Cycles Per Second. Synonomous with the word Hertz or Hz.
CPU
Acronym for Central Processing Unit. The main computing part of a computer In PC's this is a single integrated circuit (microprocessor) that handles data storage & retrieval and logical operations. In large computers it can be a collection of chips on a printed circuit board.
Cray
A manufacturer of well-known supercomputers in the 70's and 80's. For their time, they were incredibly fast and powerful machines but very expensive. Rapid advances in smaller computer technologies made them obsolete quickly and the company faded away in the mid '90's.
Crash
An unrecoverable program or system malfunction that causes the computer to stop responding. The only possibility is to restart the machine.
Crossfade
To gradually supplant one audio signal with another.while the overall amplitude remains relatively constant.
Crossfade looping
A sample-editing feature found in many samplers and most sample-editing software, in which some portion of the data at the beginning of a loop is mixed with some portion of the data at the end of the same loop, so as to produce a smoother transition between the end and the beginning when the loop plays.
Crossover
An electronic circuit that separates an audio signal into two or more bands of frequencies and routes each to a different output.
Cross-switching
A velocity threshold effect in a synthesizer in which one sound is triggered at low velocities and another at high velocities, with an abrupt transition between the two. If the transition is smooth rather than abrupt, the effect is called crossfading rather than cross-switching. Cross-switching can also be initiated from a footswitch, LFO, or some other controller. Also called velocity switching.
Crosstalk
Undesirable leakage of one audio channel's signal into another channel.
CRT
Acronym for Cathode Ray Tube. The large vacuum tube in a computer monitor or television that delivers the image to the user. In the tube a magnetically deflected beam of electrons sweeps across the phosphor dots coating the front screen causing them to glow momentarily.
Cutoff frequency
The frequency in cycles per second at which a filter is set to reduce amplitude. This can be a deceptive measurement because no filter can pass frequencies on one side of the cutoff unheeded while completely blocking the frequencies on the other side. There is always some slope to the amplitudes of surrounding frequencies.
Cyberspace
Term coined by novelist William Gibson to describe the world of data created by the millions of computers connected worldwide by online communications.

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DAC or D/C converter
Digital-to-analog converter A circuit that changes the sample words put out by a digital audio device into analog fluctuations in voltage that can be sent to a mixer or amplifier. All digital synthesizers, samplers, and effects devices have DACs (rhymes with fax) at their outputs to create audio signals.
Daisy chain
A bus configuration of MIDI devices. In other words a single electrical circuit connects all hardware like beads (or daisies) on a string. Most devices therefore would have their THRU ports connected to the next device's IN port.
Damping
The ability of an amplifier to prohibit unwanted speaker cone movement
DAT
Acronym for Digital Audio Tape. A standard magnetic tape cassette medium for storing digital audio data. The cassette resembles a miniature VHS video cassette and like that medium requires a helical, quickly revolving tape head to record and play back data from a relatively slow-moving tape. DAT tapes store two channels of 16 bit audio data plus timing information.
Data bus
The copper traces on a motherboard that allows information (data) to be circulated among the central processor, RAM, and other connected devices.
Data byte
One of two types of bytes (Data and status) called for by the MIDI spec and a part of any multibyte MIDI message. Data bytes are characterized by holding a 0 in the most significant bit position. While the status byte conveys the basic command in every MIDI message, data bytes add information to make the command specific. Example: Status byte says 10010000 or "Turn on a note on channel 2.." Data bytes add 00111100 "Note #60 (middle C)," and 01111111 "Velocity 127 (attack as hard as possible)."
Data compression
Making data fit into a smaller space or bandwidth. Compression is most often accomplished by eliminating repetitive strings of 1's and 0's and substituting descriptions. When compressed files are received, they must be translated to their original expanded form to be useful
Data decrement
MIDI control change code (01100001) that reduces the value of the selected controller by 1.
Data dump
A packet of memory contents being transmitted from place to place (usually in the form of MIDI system-exclusive data) or stored to a RAM card.
Data entry
MIDI control change codes (00000110 and 00100101) that specify a setting for a selected controller. Because two codes can be used to specify the setting, the range of possible values is between 0 and 16,129 (127 x 127 ).
Data increment
MIDI control change code (01100000) that increases the value of the selected controller by 1.
Daughterboard
A small printed circuit board that plugs directly into a larger board. This design may result from space constraints or a desire to make one part of a motherboard upgradeable.
dB
Acronym for DeciBel. A relative measure of powers often used to measure sound intensity levels (SPL). It is common to give the range of human loudness perception as 0dB (the threshnold of hearing) to 120 dB (the threshhold of poin). Because the decibel scale is a logarithmic measure,each added 10 points on the scale represents 10 times the power of the lower number. Thus 120 dB is actually a trillion times more powerful than 0 dB (10 to the 12th power). A two fold increase in power corresponds to a 3 dB increase.
dBu
A type of decibel measurement often applied to audio signal voltages. While the plain decibel scale can only compare the relative powers of two signals, dBu assigns a reference level of .0775 volts as 0 dB and thus can specify the power of a single source.
dBv
Another type of decibel measurement often applied to audio signal voltages. While the plain decibel scale can only compare the relative powers of two signals, dBu assigns a reference level of 1 volt as 0 dB and thus can specify the power of a single source.
DBX
A common noise reduction technology often applied to analog tape recording. It works by amplifying a band of frequencies in the original recorded material that is the same as normal tape hiss and then compressing the entire signal. On playback the signal is expanded and the boosted frequency band is reduced in amplitude which brings the recorded material back to normal but cuts out as much as 30 dB of system-added tape noise.
DC
Acronym for Direct Current. A non-flipping electrical pressure. In direct current the electricity flows only in one direction. Contrast with alternating current in which the electricity flows first one way then the opposite.
DCA
Acronym for Digitally Controlled Amplifier. A generic name for the circuit of a synthesizer that changes the tone's amplitude over time. The shape of this change is called the amplitude envelope or often the ADSR for Attack, Decay, Sustain, Release.
DCO
Acronym for Digitally Controlled Oscillator. A generic name for the circuit of a synthesizer that creates a complex waveform.
DCW
Acronym for Digitally Controlled Wave modulator. A generic term for the circuit of a synthesizer that shapes the complexity of a waveform over time.
Decay
The second of the four segments of a typical ADSR envelope. The decay control determines the amount of time it takes for the envelope to fall from the peak reached at the end of the attack segment to the sustain level. See ADSR.
Decibel
Literally, one tenth of a Bel (a telephone transmission loss unit named after Alexander Graham Bell).The decibel is a convenient measure of relative powers often used to measure sound intensity levels (SPL). It is common to give the range of human loudness perception as 0dB (the threshnold of hearing) to 120 dB (the threshhold of pain). Because the decibel scale is a logarithmic measure, each added 10 points on the scale represents 10 times the power of the lower number. Thus 120 dB is actually a trillion times more powerful than 0 dB (10 to the 12th power). A two fold increase in power corresponds to a 3 dB increase. In order to measure a signal in dB, you need to know what level it is referenced to. Commonly used reference levels are indicated by such symbols as dBm, dBV, and dBu.
Decimal
A counting system that uses ten unique digits, 0 to 9. In order to represent numbers larger than 9, multi-digit numbers are created in which each place represents ten times the place to its right.
Default
A hardware or software setting that is in effect before the user changes it. It is usually the most logical or useful setting for that particular function and is set at the factory or by the user during a previous set up session.
Defragment
To bring individual files stored in memory or on a disk into unified wholes. When drives or memory have experienced much continuous use, it is common for files to be broken apart and stored in any available space with pointers to keep the computer reading the sections in the proper order. However, this slows down the machine. Defragmenting restore full speed to file reading and writing.
Delay
(1) The first stage of a five-stage DADSR envelope, which delays the beginning of the envelope's attack segment. (2) A control function that allows one of the elements in a layered sound to start later than another element. (3) A signal processor, used for flanging, doubling, and echo, that holds its input for some period of time before passing it to the output, or the algorithm within a signal processor that creates delay
Delta
A measurement representing the change between two numbers
Dialog Box
An onscreen text box found in graphical user interfaces that gives users information and explains options.
Didymean comma
The difference between a perfect double octave and a couble octave derived by stacking four perfect fifths (example: A-E-B-F#-C#) and subtracting a perfect major third.
Difference tone
A perceived tone whose frequency results from the difference two other frequencies sounded together. As an example, A440 and F#743 cause a perception of sharp D303. This perceived frequency is not physically present in the sound sources.
Diffraction
The bending of sound waves around an obstacle. It is most apparent in low frequencies.
Digital
Numbered. It refers to the representation of real world phenomena by regularly spaced, discrete measurements. The more closely spaced the measurements, the more fidelity the digital representation can have to the original. Using computer-type binary arithmetic operations. Digital music equipment uses microprocessors to store, retrieve, and manipulate information about sound in the form of numbers, and typically divides potentially continuous fluctuations in value (such as amplitude or pitch) into discrete quantized steps. Compare with analog.
 
DIMM
Acronym for Dual Inline Memory Module. A small circuit board containing RAM chips that can be inserted inro a computer to increase available memory. DIMMs differ from SIMMs (Single Inline Memory Modules) by having separate contacts on either side of the board
DIN
Acronym for Deutsche Institut fur Normung. A set of standards for electrical connections among other things. A MIDI plug is actually a 5 pin DIN plug.
DIP
Acronym for Dual Inline Package. A chip design in which leads from the internal integrated circuit protrude from opposing sides of the rectangular protective box.
DIP Switch
A set of on-off switches built into a Dual Inline Package (see DIP). They are often mounted on the printed circuit boards small electronic devices when it is necessary to allow the user to configure certain aspects of the device for specialized uses.
Dispersion
A speaker's angle of effective coverage. Most often defined as the area in front of the speaker where the sound intensity level is no less than 6 dB lower than the center line intensity for a given frequency.
Distortion
An undesireable alteration of a sound or waveform. All sound reproduction devices cause some distortion, and there are many different causes including: Intermodulation distortion caused by two frequencies beating against each other, harmonic distortion caused by signal strength greater than a circuit's capacity, transient distortion caused by a mechanical system's inertia in trying to reproduce rapid amplitude changes, etc
Distributed computing
A computation process split among several machines. Many 3D animation programs allow their number intensive image creation work to be done over a network by many computers working on different parts of the same animation.
DMA
Acronym for Direct Memory Access. The ability of some circuits and expansion cards to transfer data to RAM without routing it through the central processor. This usually speeds up information transfers.
DNS
Acronym for Domain Name Service. Computers on the Internet whose main function is to convert a requested web site's name into its actual numerical address. It does this by maintaining a large database of registered domain names.
Documentation
Textual information detailing the operation of hardware or software.
Document icon
One of five types of icons used by the Macintosh Finder interface. The icon, a small picture, represents something created with a computer application program.
Dolby
The most common noise reduction technology often applied to analog tape recording. Types linclude B C and HX for consumer level tape decks and A and SR for professional recording equipment. Dolby works by amplifying low level signals at selected frequencies in the original recorded material and then attenuating them-- along with any added tape noise-- on playback. HX Dolby also boosts high frequency signals during recording.
Domain
A classification system used int the United States to group similar types of Internet sites. The last three letters of a site name reveal the type of site: .com = commercial, .edu = education, .gov = government, .mil = military, .net = network, .org = organization.
Domain Name
An readable slubstitute for the numeric address of a computer on the Internet. Every computer on the Net is assigned an IP address, a series of four numbers separated by dots (e.g., 155.20.99.21). A domain name is a series of words that's easier for people to remember, such as www.mybusiness.com.
DOS
Acronym for Disk Operating System. The basic instruction set of a personal computer. It allows the main unit to communicate with peripherals like storage devices, monitor, keyboard, printer, etc.
Dot pitch
A measure of video monitor resolution. It shows the distance from one phosphor to the next of the same color in millimeters. For example, an advertised .25 dot pitch means that two red phosphors are a quarter millimeter apart. A .28 dot pitch is considered good for computer monitors.
Download
To receive a file sent from another computer via a modem or other network connection.
DPI
Acronym for Dots Per Inch. It is a measure of how much visual resolution a peripheral device like a printer or monitor can display. A standard 640 by 480 video monitor is often said to be 72 to 75 DPI. Basic laser printers output at 300 DPI or 600 DPI. Linotronics machines used for magazine printing output 1200 to 2400 DPI.
DPSK
Acronym for Differential Phase Shift Keying. This is a common method of transmitting digital data over analog telephone lines. Because it uses the relative position of voltage fluctuations as well as their frequency to represent 1's and 0's, it allows more data than the bandwidth would normally permit.
DRAM
Acronym for Dynamic Read Only Memory. Memory chips that must have their contents constantly refreshed. This is the most common type of RAM because it is less complex to manufacture and consume less power than the more stable Static RAM; however, it is usually slower and requires circuitry that reads and rewrites the 1's and 0's hundreds of times per second.
Driver
A small program that allows communication between a computer and a specific peripheral device. Most third party printers, scanners, etc. come with their own software drivers to link them to a computer's operating system.
Drop-frame
A type of SMPTE timecode that omits two frames every minute except for every tenth minute. Frames are dropped due to the difference between color and black-and-white television signal formats.
Dry
Consisting entirely of the original, unprocessed sound. The output of an effects device is 100% dry when only the input signal is being heard, with none of the effects created by the processor itself. Compare with wet.
DSDD
Acronym for Double Sided, Double Density. A floppy disk format that stores approximately 720,000 bytes of data. Compare to the newer High Density format which stores approximately 1,400,000 bytes or the outmoded Single Density disk that stored 360,000 bytes.
DSHD
Acronym for Double Sided, High Density Disk. A floppy disk format that allows the storage of approximately 1,400,000 bytes of data on a single disk. It refers primarily to how the magnetic markers are laid down when the blank disk is formatted rather than to the physical capacity of the disk. 3 1/2" High Density disks are distinguishable by a second hole and the letters HD on the casing. Internally they may be the same as double density disks.
DSP
Digital signal processor. Broadly speaking, all changes in sound that are produced within a digital audio device, other than changes caused by simple cutting and pasting of sections of a waveform, are created through DSP's. A digital reverb is a typical DSP device.
Dumb Terminal
A terminal usually consisting of a monitor and keyboard that doesn't contain an internal microprocessor, responds to simple control codes, and usually displays only characters and numerals.
Duplex
A communications parameter that determines how the keystrokes you type appear on your screen. Half dup]ex means that your keystrokes appear as a direct result of your typing them. Full duplex means that keystrokes appear as a result of the modem to which you're connected echoing them back to you.
Duration
One of four objective or measurable attributes of sound. It represents the actual time span over which a sound is being produced
Dynamic microphone
A sound to electricity transducer that works by allowing a wire coil attached to a sound activated diaphram to vibrate through a magnetic field. This induces fluctuating electrical current in the coil
Dynamic RAM
Memory chips that must have their contents constantly refreshed. This is the most common type of RAM because it is less complex to manufacture and consume less power than Static RAM; however, it is usually slower and requires circuitry that reads and rewrites the 1's and 0's hundreds of times per second.
Dynamic range
The difference between the loudest sound a device can produce without distortion and the quietest sound that it can acceptably produce.
Dynamic voice allocation
A system found on many multitimbral synthesizers and samplers that allows voice channels to be reassigned automatically to play different notes (often with different sounds) whenever required by the musical input from the keyboard or MIDI.

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Early reflections
A reverb algorithm whose output consists of a number of closely spaced discrete echoes, designed to mimic the bouncing of sound off of nearby walls in an acoustic space.
Echo
A distinct reiteration of a sound after more than 50 milliseconds. Indistinct, multiple reiteration is called reverberation.
ECS
Acronym for Electronic Courseware Systems. An active publisher of music related software particularly that used in music education.
Edit buffer
An area of memory used for making changes in the current patch. Usually the contents of the edit buffer will be lost when the instrument is switched off; a write operation is required to move the data to a more permanent area of memory for long-term storage.
Editor/librarian
A piece of computer software that allows the user to load and store patches and banks of patches (the librarian) and edit parameters (the editor).
EEPROM
Acronym for Electronically Erasable Programmable Read Only Memory. A normally non-volatile memory chip that can be erased and rewritten if enough voltage is applied.
Effects
Any form of audio signal processing -- reverb, delay, chorusing, flanging, etc.
Efficiency
The ratio of useful power output to power input. The efficiency of speakers is rated by stating the SPL (sound pressure level) at 1 watt continuous input power measured 1 meter in front of the speaker.
Eighth cranial nerve
The nerve bundle that connects the organ of Corti to the brain.
E-mail
Electronic Mail. Refers to messages that are sent via computers on a network or to the system used for sending such messages.
Emulate
In computing, the forcing of one type of machine to adopt the look and feel of an unlike machine. For example, SoftWindows forces a Motorola-based Macintosh to work like an Intel-based PC.
Envelope
A shape that changes as a function of time. The shape of a synthesizer's envelope is controlled by a set of rate (or time) and level parameters. The envelope is a control signal that can be applied to various aspects of a synth sound, such as pitch, filter cutoff frequency, and overall amplitude. Usually, each note has its own envelope(s).
Envelope generator
A device that generates an envelope. Also known as a contour generator or transient generator, because the envelope is a contour (shape) that is used to create some of the transient (changing) characteristics of the sound. See ADSR, envelope.
EOX
Acronym for End Of Exclusive. A one byte MIDI code that signals the end of a System Exclusive data string. It must be used because SysEx data can be of any length, and only a pre-determined signal can allow the receiving instrument to stop assuming that the incoming string of data is related to the previously sent SysEx command.
EPROM
Acronym for Erasable Programmable Read Only Memory. A normally non-volatile memory chip that can be erased with ultraviolet light and rewritten electrical.
EQ
Acronym for EQualization. Raising or lowering amplitude of various ranges of the audio spectrum to achieve a desired overall balance of sound for a specific environment.
Equalizer
An electronic circuit designed to raise or lower amplitude of various ranges of the audio spectrum to achieve a desired overall balance of sound for a specific environment. Two types exist: Graphic equalizers contain numerous sliders or knobs each representing a preset band of frequencies. Parametric equalizers have a knob to set the exact frequency band desired and another knob to raise or lower its amplitude.
Equal temperament
One of many tuning systems created over the course of music history to accomodate the fact that scales derived from static acoustically perfect intervals create imperfect octaves. In equal temperament rather than trying to tune any selected interval perfectly, all intervals are slightly out of tune. The smallest interval, a half step, is created by multiplying a note by the twelfth root of 2 or 1.059463094.) Equal temperament has been the accepted method of tuning for over two centuries on staticly tuned instruments like keyboards.
Ethernet
A popular, fast networking method found in most small computer networks. Several varieties of Ethernet exist using wire, coaxial cable or glass fiber. These deliver between 10 million and 100 million bits per second data transfer rates.
EtherTalk
Apple software that allows a Macintosh to link to Ethernet networks.
Excursion
The in/out movement of a speaker cone when voltage is applied.
Expansion board
A printed circuit that attaches to a motherboard via a slot and provides expanded capabilities to the computer. Common applications include internal modems, sound & MIDI, video enhancement, and memory upgrades,.
Expansion slot
A receptacle attached to a computer's motherboard into which special purpose printed circuit boards can be inserted. They are connected to the CPU via the bus wires.
Explorer
Microsoft corporation's browser software that allows access to the world wide web.
Exponential
An expression of increase or decrease based on how many times it multiplies itself rather than how many times it is added to itself. It is usually used to express large or fast changes.
Exponential horn
A high frequency speaker constructed with a horn whose flare represents the square of the distance from the vibrating diaphragm.
Extended keyboard
A computer keyboard with 101 keys including function keys, numeric keypad, and other special purpose keys.
EZ drive
A high-capacity removeable media storage device made by Syquest. Created to counter Bernoulli's popular and inexpensive Zip drive, an EZ cartridge holds 135 million bytes of data compared to the 105 megs of a Zip cartridge, reads and writes faster, and has more flexible SCSI connectability. Good technology but bad marketing: Syquest is now out of business.
F
Hexadecimal equivalent of the decimal number 15.
Fader
A movable straight line lever that acts as a variable resistor to electrical current. It is used on audio equipment to control an audio signal's amplitude.
FAQ
Acronym for Frequently Asked Questions. A FAQ page is often used in digital documents to cover
Far field
A distance from a speaker that is at least double the length of the wave being produced.
FC-AL
Acronym for Fiber Channel Arbitrated Loop. One of several proposed standards for fast transfer of data between a computer and its peripheral devices. It promises a 100 million byte per second transfer rate with up to 127 devices attached to the same bus.
Feedback
A high sound created by audible output leaking back to the system's live microphone input.
Femto
A quadrillionth or 1/1,000,000,000,000,000.
Fetch
An FTP program for the Macintosh. Fetch allows users to transfer text or binary files to servers through an easy-to-use graphic user interface.
FF
Hexadecimal enumeration of the decimal number 255.
FFT
Fast Fourier transform. A quick method of performing a Fourier analysis on a sound. See Fourier analysis.
FIFO
Acronym for First In, First Out. Type of buffer that keeps data in order which is necessary in a MIDI sequencer. Think of it as an escalator as opposed to the LIFO buffer which would be more like an elevator.
File server
The main computer in a network. It serves as the central storage area and data router for many connected computers.
Filter
(1) A device for eliminating selected frequencies from the sound spectrum of a signal and perhaps (in the case of a resonant filter) increasing the level of other frequencies. See lowpass filter.
Filter
A device (MIDI filter) that eliminates selected messages from the MIDI data stream.
Firewalls
Special computers that are set up on a network to prevent intruders from stealing or destroying confidential data.
Firmware
Permanantly stored software like the programs burned into ROM chips.
Flame
To berate with hostile E-mail. It may happen to users who ask stupid questions, type messages in all capital letters, or display commercial postings.
Flanger
A sound processor that produces a "swoosh" or sweeping effect. The effect is caused by delaying a copy of the audio signal for a varying length of time and then remixing it with the original. This causes varying phase shifts in the harmonics.
Flat response
The ability of an audio device to produce the same amplitude at any frequency throughout the range of human hearing, 20 - 20,000 cps. Response curves are plotted on a logarithmic scale
Fletcher-Munson curve
A graph showing how much amplitude is required at various frequencies for typical human subjects to report a perception of constant loudness. Also called equal loudness countours, Fletcher-Munson curves reveal that humans are most sensitive to sound in the range between 1000 and 5000 cps.
Floppy disk
A common removeable medium for non-volatile storage of computer software and data. Because bits are encoded magnetically, they allow for easy erasing and rewriting. The most common type for modern PC's is the 3 1/2" plastic shelled variety with a capacity of either 720,000 bytes (double density) or 1,400,000 bytes (high density).
FLOPS
Acronym for Floating Point Operations Per Second. A standard measure of a computer or microprocessor non-integer processing speed.
FM synthesis
FM is an acronym for frequency modulation and means a periodic change in the frequency of a signal. When the period is slow (below 20 cps), FM is perceived as vibrato or tremelo. However, when the period of the modulating wave is in the audio range (above 20cps), FM is perceived as a change in tone color. FM synthesizers excel at imitating metallic sounds like bells and Rhodes pianos because it is easy to create complex waveforms containing non-integer related harmonics.
Folder icon
One of the 5 basic icons or images used by the Macintosh graphic user interface. A folder is merely a storage area for other icons: applications, documents, or other folders. It helps the user organize items in the Macs outline-like hierarchical file system.
Foley
A studio that specializes in adding sound effects to motion pictures and animations.
Foot controller
A MIDI continuous control change message usually assigned to a device's loudness. The foot control message itself is most often sent by a pedal.
Formant
A resonant peak in a frequency spectrum. For example, the variable formants produced by the human vocal tract are what give vowels their characteristic sound.
Forum
An area on an electronic bulletin board or online service where people with a common interest, such as pet canaries or rap music, can post notes to one another. Forums are frequently used to ask questions, share information, or debate ideas.
Fourier analysis
A technique, usually performed using a DSP algorithm, that allows complex, dynamically changing audio waveforms to be described mathematically as sums of sine waves at various frequencies and amplitudes. See DSP.
Fourier theorem
The postulate made by Jean Baptiste Fourier (1768 - 1830) that all complex waveforms can be reduced to a collection of single frequency waveforms. This idea turned backwards makes additive synthesis possible.
FPS
(See Frames per Second below.)
FPU
Acronym for Floating Point Unit. The circuit of a cpu that deals with fractional numbers.
Frame
The basic unit of SMPTE time code, corresponding to one frame of a film or video image. Depending on the format used, SMPTE time can be defined with 24, 25, 30, or 29.97 frames per second. See SMPTE time code.
Frame
A subdivided area within a single Web page. A frame has its own URL and Web page. Links in one frame can be made to change the contents displayed in other frames.
Frames per second (fps)
The number of video frames that elapse per second, as defined by the four SMPTE/EBUtimecode fps standards (24 for film, 25 for European or PAL TV, 30 for NTSC B&W TV, and 29.97 for NTSC Color TV).
Free MIDI
A Macintosh operating system extension developed by Mark of the Unicorn that enables different programs to share MIDI data. For example, a sequencer could communicate with a librarian program to display synthesizer patch names -- rather than just numbers -- in the sequencer's editing windows.
Freewheeling
A condition in which a synchronizer continues to generate timecode even when it encounters dropouts in the timecode source, or in which a digital audio playback device continues to generate audio in the absence of (or while ignoring) a timecode input.
Freeze
On a computer, a state in which the mouse pointer locks to a single position and the machine does not respond to user input. Even in the most carefully made hardware and software, freezes are unavoidable over a long term. Smart computer users avoid the frustration they cause by saving their work frequently.
Frequency
One of four objective, that is measureable, attributes of sound. The number of regularly spaced fundamental vibrations that occur in one second. It is usually stated in Hz (Hertz), sometimes in cps (cycles per second). For complex tones it is the lowest component, the fundamental, that is measured.
Frequency modulation (FM)
A periodic change in the frequency of a signal. When the period is slow (below 20 cps), FM is perceived as vibrato or tremelo. However, when the period of the modulating wave is in the audio range (above 20cps), FM is perceived as a change in tone color. FM synthesizers excel at imitating metallic sounds like bells and Rhodes pianos because it is easy to create complex waveforms containing non-integer related harmonics.
Frequency response curve
A measure of how well an audio device reproduces the audible spectrum of frequencies. It is usually plotted on a graph showing frequencies horizontally and reproduction ability vertically. A graph is only partly revealing since many factors interact to influence frequency response.
FSK
Acronym for Frequency Shift Keying. A technology for syncronizing two or more pieces of playback hardware. It works like a metronome-- when the receiving instrument detects a change in frequency, it steps ahead one unit of time. FSK is also used to send binary data over analog circuits like phone lines. Each change of frequency represents a change from 0 to 1 or the reverse. Since most analog phone lines have a limited frequency range (up to about 4000 Hz), FSK is only capable of transmitting at a little under half of that speed or about 1800 bits per second. Higher speeds must use newer methods.
FTP
Acronym for File-transfer protocol . A standard method of Internet communication that lets you connect to a site, search through the available files, and download any file, document, or program available.
Full bit set
All ten binary digits that are actually transmitted to represent a byte in asynchronous computer communication (like MIDI). The full bit set includes a start bit (a 0 or current on) which signals that a byte is about to arrive, the 8 bits of the byte, and a stop bit (a 1 or current off) that signals the end of that byte.
Full range
Usually considered the complete audio spectrum to which humans are sensitive: approximately 20 cycles per second to 20,000 cycles per second. The upper end of this range varies widely among people and tends to lessen with age. Full range in standard FM broadcast is considered 50 cps to 15,000 cps. Normal telephone audio operates between 400 and 4,000 cps.
Fundamental
The lowest audible frequency in a complex musical tone. (This excludes low frequency oscillations like vibrato.) The fundamental usually carries more energy than the other harmonics and so identifies the pitch of the note to the listener.
G3
Marketing term applied to the PowerPC 750, the third generation of IBM and Motorola's PowerPC RISC microprocessors. The 6.5 million transistor chip is optimized to run the Macintosh OS, uses backside level 2 cache technology, and features very low power requirements for maximum efficiency and low heat dissipation. It can execute up to 3 instructions per clock cycle which allows a speed of 671 MIPS or a 16.1 S SPECint rating for a 366 MHz version of the chip.
Gain
The increase in signal voltage created by an amplifier. Because it is usually expressed as a decibel ratio of output to input voltage, it can be either a positive or negative number.
Gate
In computers, an electronic circuit that performs Boolean logic comparisons like AND, OR, and NOT. In audio devices, a circuit that allows a signal to pass only after a specified level is reached.
Gateway
Similar to bridges, gateways connect incompatible applications or networks so data can be transferred.
GB
Acronym for gigabyte, one bilion bytes. More precisely for computers, which use binary math, it represents 2 to the 20th power, or 1,073,741,824 bytes.
General MIDI (GM)
An extension to the MIDI specification introduced in 1993. It was designed to standardize many MIDI paramaters so that sequences would sound more-or-less the same played on any manufacturer's device. The standardization included individual and group instrument mapping (Preset #1 will always sound like a grand piano: Presets 1 - 10 will always sound like keyboards). Channel 10 would always be assigned as the untuned percussion channel. 24 voice multitimbral polyphony would be standard.
General purpose controller
A MIDI control change message that can be used for non-standardized applications. There are 8 general purpose controllers defined in the MIDI spec, 4 continuous and 4 switch. The continuous ones combine MSB and LSB for 14 bit resolution or 16,384 levels of control.
GIF
Acronym for Graphics Interchange Format. A compression algorithm created by Compuserve to reduce the file size, and thus the transfer time, of pictures over networks. It limits the colors to 256, though these 256 hues can be any that fit the picture. GIF is the standard format for graphics on the Internet.
Gig
Shortened form of giga meaning a billion. However when referring to binary devices it means 2 to the 30th power or 1,073,741,824.
Giga
A billion. However when referring to binary devices it really means 2 to the 30th power or 1,073,741,824.
Gigabyte
One billion bytes. More accurately 2 to the 30th power (1,073,741,824) bytes.
Gigaflop
Acronym referring to billions of floating point operations per second. A measure of a computer's speed in performing fractional (decimal point) math.
Glide
A function, also called portamento, in which the pitch slides smoothly from one note to the next instead of jumping over the intervening pitches.
Glitch
A temporary hardware malfunction.
GM
Acronym for General MIDI, an extension to the MIDI specification introduced in 1993. It was designed to standardize many MIDI paramaters so that sequences would sound more-or-less the same played on any manufacturer's device. The standardization included individual and group instrument mapping (Preset #1 will always sound like a grand piano: Presets 1 - 10 will always sound like keyboards). Channel 10 would always be assigned as the untuned percussion channel. 24 voice multitimbral polyphony would be standard.
 
Go Word
A keyword you enter while in CompuServe to search for a particular subject; same as jump in Prodigy and Keyword in America Online.
Gopher
A menu-driven, search and retrieval tool providing access to databases, text files, and other resources on the Internet.
Granular synthesis
A type of tonal synthesis in which algorithms control the metamorphosis of sequential small bursts of sound (grains). Each grain is normally between 5 - 20 milliseconds in length-- not long enough to be perceived as a pitch. Granular synthesis is similar in concept to motion picture film in which many sequential still pictures give the illusion of animation, however the time period between bursts of sound need not be static.
Graphic editing
A method of editing parameter values using graphic representations (for example, of envelope shapes) displayed on a computer screen or LCD.
Graphic EQ
A sound processing device that allows its user to raise or lower the amplitude of individual portions of the audio spectrum through faders. The positions of the many sliders, each representing a third to a half of an octave, collectively look like a picture (graphic) of a frequency response curve
Ground
An electrical connection to the earth designed to prevent shock hazard. The middle prong of a three pronged AC power plug is the ground connecting the chasis of an electrical device to the earth. Also, any point of an electronic circuit that has a zero voltage.
Ground loop
A low pitched hum caused by electrical fluctuations in the common AC ground wire from nearby electrical devices.
GS
Acronym for General Standard. A Roland-created extension to General MIDI.
GUI
Acronym for Graphic User Interface. A system of communicating with a computer that relies on images rather than words. Graphic User Interfaces are distinguished by pictorial icons and command menus on the screen and by input devices like a mouse or trackball which allow the user to point at and click on these screen elements. Microsoft Windows and the Macintosh Desktop are GUIs.
Haas effect
Ability of human hearing that blends the first 20 milliseconds of aural events into one event. It helps to localize sounds in space.
Hacker
Slang term for a technically sophisticated computer user who spends a lot of time trying to break into networked computers.
Handshaking
Communication of synchronization signals between two digital devices that forces them to step together at the same time. The purpose of this synchronization is to allow faster data interchange.
Hard disk
A common non-removeable medium for storing computer data. Hard drives consist of encased spinning platters coated with magnetic material which can be read from or written to by rapidly positionable arms. Besides being much more capacious than floppies (40 megabytes to 9 gigabytes at present) they are also much faster both for finding and reading/writing data.
Hard disk recording
A computer-based form of tapeless recording in which incoming audio is converted into digital data and stored on a hard disk.
Hardware
The physical, touchable devices that comprise a computing system as opposed to software which refers only to the programs it runs and has no physical connotation.
Harmonic
A frequency that is a whole-number multiple of the fundamental frequency. For example, if the fundamental frequency of a sound is 440Hz, then the first two harmonics are 880Hz and 1,320Hz (1.32kHz). See overtone.
Headroom
The difference between the average operating level of an audio system and its peak capacity before distortion begins to occur. Headroom is necessary to allow for normal variations and unexpected spikes in amplitude. Audio compressors and limiters allow the average operating level to be much closer to the peak capacity because they automatically depress the signal amplitude as it nears the limit; however, they also render a false impression of the original sound.
Help menu
An addition to newer versions of the Macintosh OS which appears on the menu strip. It supposedly offers online assistance for operating the current application; however, many programs don't make luse of it.
Hertz
Synonym for cycles per second named after German physicist,Heinrich Hertz (1857 - 1894). The term is now commonly used to refer to any vibratory motion including both mechanical (sound), and electromagnetic (radio, television, light and above).
HEX
Short for hexadecimal. A counting system that uses sixteen unique digits, 0 to 9 and A, B, C, D, E, F. In order to represent numbers larger than F (decimal 15), multi-digit numbers are created in which each place represents sixteen times the place to its right. For example the number FF represents decimal 255 because the leftmost F equals 15x16 and the rightmost F equals 15 x 1 for a total of 255. Hexadecimal enumeration is efficient for representing units like digital words and bytes because they break evenly into four bit nibbles each capable of being represented by a single hexadecimal digit.
Hexadecimal
A counting system that uses sixteen unique digits, 0 to 9 and A, B, C, D, E, F. In order to represent numbers larger than F (decimal 15), multi-digit numbers are created in which each place represents sixteen times the place to its right. For example the number FF represents decimal 255 because the leftmost F equals 15x16 and the rightmost F equals 15 x 1 for a total of 255. Hexadecimal enumeration is efficient for representing units like digital words and bytes because they break evenly into four bit nibbles each capable of being represented by a single hexadecimal digit.
HFS
Acronym for Hierarchical File System. An organizational method of placing and finding stored files based on categories and sub-categories like a topical outline. The Macintosh computer uses a Hierarchical File System to locate documents in named folders which may themselves be enclosed in folders.
Hierarchical File System
An organizational method of placing and finding stored files based on categories and sub-categories like a topical outline. The Macintosh computer uses a Hierarchical File System to locate documents in named folders which may themselves be enclosed in other folders through several levels.
High
In digital electronics, the electrical pressure on state as opposed to 'low,' meaning pressure off. Because there is apt to be some minor alternation of pressure in electrical circuits at all times, the definition of 'high' state is usually set at +5 volts.
High impedance
An electrical resistance greater than 2,000 ohms. (Less than 2,000 ohms is called low impedance. It is important to match impedances of connected electronic devices like microphones and mixers in order to achieve the highest signal transfer with minimum distortion.
High pass filter
An electronic circuit or device designed to transfer only high frequencies of a sound spectrum while reducing the power of all frequencies below a selected level.
High Sierra
A standard for organizing data on a CD-ROM. It was an attempt to create a CD-ROM which could be read across many different platforms. It is similar to the common ISO 9660 format
Hiss
Aperiodic sound (noise) usually associated with audio electronic devices and particularly analog tape. All electronic devices produce hiss; the trick is to make the audio signal so much louder than the background noise that the latter becomes insignificant.
Hit
Colloquial term meaning a single visit to a Web page
Home Page
Also referred to as a Web page, a home page provides a link between documents and loads automatically when you start a program in the World Wide Web.
Host
 
HTML
Acronym for Hypertext Markup Language. A standard for formatting text and including links to other sites common to the world wide web. HTML is basically plain ASCII text with English-like commands inserted to indicate formatting.
HTTP
Acronym for HyperText Transport Protocol. A common method for sharing data over the World Wide Web which allows for hypertext links to other sites.
Hum
Regular fluctuation in an audio signal caused by induction of nearby powerful AC devices. Because AC lines operate at 60 cycles per second, hum occurs at 60 Hertz or some integer multiple of it (120, 180, 240, etc.)
Hyperlink
A connector that jumps you to different documents on the World Wide Web when you select highlighted words.
Hypermedia
The joining together of video, sound, graphics, animation, and other elements to form an association of independent yet interrelated topics. Rather than moving in a linear or sequential format, hypermedia (like hypertext) lets the user use the human thought process to make associations between topics. The user can navigate from subject to subject in search of information on related topics.
Hypertext
A presentation of information in which text, sounds, images, and actions are linked together through com- plex associations that let users browse through related topics regardless of the order in which the topics are presented~ The World Wide Web is built upon this concept of independent yet interrelated documents and graphics~ If the data is primarily text~based~ the information is called hyper~ text instead of hypermedia
Hz
IC
Acronym for Integrated Circuit
IDE
Acronym for Integrated Drive Electronics. A popular hard drive configuration that has a built-in controller. They are ubiquitous on Intel based PC's. (Macintoshes usually use SCSI drives.) IDE drives are usually less expensive to integrate into a PC, but they allow only 2 to 4 devices on the bus as opposed to SCSI's 7 devices.
IMA
Acronym for International MIDI Association. An organization that oversees the development of the MIDI standard worldwide.
Imagemap
On a web page, a graphic that has been divided into invisible sectors each of which is linked to another Web page or object. When the user clicks on a sector, the browser goes to the designated location.
IM distortion
Acronym for InterModulation Distortion. System created sounds that result from combinations or differences of frequencies being fed through the audio chain.
Impedance
Resistance to the free flow of electrons. It is expressed in Ohms and in audio equipment is usually classified as either "high" (above 2,000 ohms) or "low" (below 2,000 ohms).
Implementation chart
In
One of the three MIDI data ports (In, Out, & Thru) defined by the MIDI specification for MIDI compatible devices. The In port allows binary messages sent from an external source to enter the device and there to control its audio circuits and/or be passed on through the Thru port to another device.
Induction
A process in which small voltage fluctuations are caused by identical but higher power fluctuations in nearby, unconnected electrical devices.
Information Superhighway
A broadband thoroughfare that promises to bring consumers video on demand and inter~ active shopping~ banking~ and other services~ also known as the Infobahn
Inkjet
A type of computer controlled printer that forms characters and graphics by exploding tiny droplets of ink onto a page. Ink jet printers output almost as high quality as laser printers and are normally less expensive. However, they are considerably slower.
Inner ear
One of three divisions assigned to the human hearing organ (Outer, Middle, and Inner ear). The inner ear consists of the semicircular canals, which control balance, and the cochlea which transduces acoustical energy into the electrochemical impulses sent to the brain.
Input device
A piece of hardware that translates human action into computer understandable messages. In general computing examples include the typewriter style keyboard and the mouse. In a MIDI setup the primary example is the piano style keyboard
Integer
A whole number as in 1, 33, or 2,478 as opposed to a fractional number like 1.4 or 33.36798.
Integrated circuit
A small wafer of semi-conducting material on which many electronic components (transistors, resistors, diodes, etc. and linking wires) have been photographically imprinted
Intel
World's largest manufacturer of personal computer microprocessors. Primarily known for its 80x86 family of CPU's found in most IBM clone computers.
Interface
The method through which a computer and the user communicate. In Macintosh computers the interface is built around a standardized set of icons, menus, and other screen gadgets which all software uses in the same way making it easier for a user to operate the machine.
Interlaced graphic
An image that appears on a page in several levels of resolution so the viewer seems to see the image come gradually into focus. This type of image loads more quickly than if someone has to wait for the entire file to download.
Internet
A non~commercial, self-governing network or networks devoted mostly to commu nication and research with tens of millions of users worldwide. The Internet is not an online service and has no real central hub. Rather it is a collection of tens of thousands of networks online services and single user computers. Originally started by the U.S. military as a catastrophe-safe means of data interchange (ARPANET, 1969), it uses a packet-switching technology that does not rely on any single circuit to transfer data.
InterNIC
An organization formed in 1993 to act as a central body for registering Internet addresses and domain names.(http://ds.internic.net)
Interpolation
The insertion of averaged numbers between two known numbers. In digital audio interpolation is the basis of oversampling which smooths out the stairstep signals generated by digital to audio converters.
Intranet
A private network that uses Internet protocols (TCP/IP) to communicate. In other words it delivers and receives html encoded data.
IO
Acronym for Input/Output. Refers to the exchange of data between a computer's main unit and connected peripheral devices like keyboard, video monitor, mouse, printer, etc.
IP address
IP is an acronym for Internet Protocol. The IP address is the 32 bit numeric code attached to data packets that identifies the machine intended to receive the packet. Specialized computers called Domain name servers translate human-readable URLs (like http://www.ain-ed.com) into IP addresses (like 203.145.52.251).
IRC
lnternet Relay Chat A type of interactive communication on the Internet using realtime communicatiom. IRC is similar to a conference call in that a group of people are all talking/typing and listening/reading at the same time.
IRQ
Interrupt Request level. In IBM-PCs, a setting given to peripheral devices like soundcards and CD-ROM drives that identifies them to the computer's CPU. When the peripheral needs to communicate with the CPU, it will send an interrupt with that value. Problems will result if two or more peripherals are set to the same IRQ value.
ISDN
Acronym Integrated Services Digital Network Special connections that use phone lines to transmit digital instead of analog signals. Typical operating speed of 64 k bps per channel can be doubled to 128 k bps by combining channels.
ISO
Acronym for International Standards Organization. It is an association of many national committees whose purpose is to standardize technologies throughout the world for the sake of efficiency.
ISO 9660
The standard format for CD-ROM. It allows CD-ROM data to be read on computers of any maker who complies with the standard. (This does not mean, however, that applications can be run across platforms.) To create the standard, the International Standards Association (ISO) adopted most of an earlier manufacturer's agreement known as High Sierra format.
Jack
The receptacle into which a plug is inserted.
Java
A programming language developed by Sun Microsystems for creating small programs that can be run on any computer platform that contains a Java "Virtual Machine" program. It can also be run over a network.
JavaScript
A simplified programming language whose commands can be added directly to the HTML commands for a Web page. Java scripts are used to provide special content to certain browsers, to verify that forms can be filled out correctly, to make scrolling messages appear on Web pages, and many other functions.
Joystick
A computer input device that allows a user to move an on-screen graphic object by tilting a vertical handle toward major directions of the compass. It also incorporates a button for further interaction like clicking on a screen image or 'firing' a weapon.
JMSC
Acronym for Japanese MIDI Standards Committee. The organization thot oversees Japanese MIDI equipment manufacturers' compliance with the MIDI specification
JPEG
Acronym for Joint Photographic Experts Group. A graphic compression algorithm developed by the group that is becoming another standard for Internet pictures. JPEG compression can achieve compression levels of 100 to 1; however, it is a "lossy" format which results in noticeable rectangular artifacting at high compression levels.
Just intonation
An early tuning system created to accomodate the fact that scales derived from acoustically perfect intervals create acoustically imperfect octaves. Proposed by Pythagoras, just intonation defines a musical scale by integer-related ratios of adjacent notes' frequencies, i.e. D = 9/8 the frequency of C, E= 10/9 the frequency of D, F = 16/15 the frequency of E, G = 9/8 the frequency of F, A = 10/9 the frequency of G, B = 9/8 the frequency of A.. While just intonation works well for simple triadic harmony in one key, it produces unacceptable intervals when the harmony becomes more complex or ventures to another key.
KB
Acronym for kilobytes, one thousand bytes or, more in computer terms where binary math dominates, 2 to the 10th power or 1024 bytes.
Kernal
The lowest level of a computer's operating system. It is this set of instructions that translates higher level commands directly to hardware actions.
Keyboard
A computer input device composed of a standard typewriter key layout plus other keys that combine with the alphanumeric keys to allow efficient command execution. On a Mac these extra keys usually include: Command key, Control key, Option or Alt key, Cursor arrow keys, Function keys, Delete and Backspace keys and Escape key. On extended keyboards even more keys are included: Help key, Home, Page Up, Page Down, etc.
Keyboard scaling
A function with which the sound can be altered smoothly across the range of the keyboard by using key number as a modulation source. Level scaling changes the loudness of the sound, while filter scaling changes its brightness.
Keypad
A secondary set of keys on a computer keyboard modeled after an adding machine's numeric key layout.
KHz
KiloHertz. A measurement of periodic motion (vibration) in thousands of cycles per second.
Kilo
One thousand as in kilometer. However when associated with computers and other digital devices that work with binary numbers (as in kilobyte) it actually means 2 to the 10th power: 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 or 1024.
Knee
The frequency span a filter needs to achieve full effect. For example no audio filter can pass frequencies above A 440 at full amplitude while completely blocking those at A 440 and below.
LAN
Acronym for Local Area Network. A small computer network designed for a single group of users. It often has bridges to other LAN's and wider area networks which in turn connect together over the Internet.
Land
The normal reflective surface of a CD-ROM which in contrast with the etched depressions called Pits allow a laser light to read two different levels of reflectivity and reproduce the 1's and 0's of binary code.
Layering
Sounding two or more voices, each of which typically has its own timbre, from each key depression. Layering can be accomplished within a single synthesizer, or by linking two synths together via MIDI and assigning both to the same MIDI channel.
Laser printer
An output device through which a computer can deliver high resolution printed ('hard') copy to the user. The computer guided laser light sensitizes numerous points on a drum or rotating sleeve. These points then attract black powder which is imprinted on moving paper. Laser printers are capable of much higher resolution (300 to 1200 dots per inch) than typical mechanical dot matrix printers.
LCD
Acronym for Liquid Crystal Display. A technology used in the manufacture of flat panel screens for notebook computers, overhead projection panels, and other types of readouts (watches, calculators, etc.) It takes advantage of the ability of certain molecules to polarize light differently when electrical current is applied.
Legato
Length
LFO
Low-frequency oscillator. An oscillator especially devoted to applications below the audible frequency range, and typically used as a control source for modulating a sound to create vibrato, tremolo, trills, and so on.
LIFO
Acronym for Last In First Out. Refers to a method of data retention in which the most recently acquired byte is the first one emitted. The internal 'stack' of a CPU is a good example of a LIFO buffer. Contrast to a FIFO buffer which stores and emits bytes in the same order in which they were received.
Limiter
An audio device that prohibits amplitudes above a selected level. It is basically a compressor set to a very high level
Line level
Voltage level emitted by most electronic musical instruments, CD players, tape recorders, etc. as opposed to the lower level emitted by microphones, turntables, and guitar pickups. There are actually two different line levels: consumer at -10 dBv and professional at +4 dBv.
Linear
Progressing in a straight line. On a graph a linear progression shows a simple relationship between two phenomena.
Linear sampling
Processing sound into digital data without using any data compression algorithms.
Link
A web address attached to text or an image in a web page. Clicking on the text or image takes the user to that address (or more accurately replaces the page being viewed on the user's browser with the home page at the new address.)
Linotronics
A high end computer controlled output device designed to produce high resolution paper or film hard copy. Like laser and inkjet printers it is basically a dot matrix device but its higher resolution (typically between 1200 and 2400 dots per inch) makes it more suitable for professional applications like magazine and book publication.
Listserve
An Internet mailing list, or software that is used to send messages to members of the list.
Local control
The direct control link between a synthesizer's keyboard and its onboard tone generator. It is necessary to provide a means of turning local control off because if it is on and the instrument is also connected to a typical MIDI daisy chain setup, every note will be played twice-- once by the keyboard and immediately again through the MIDI bus.
Local off/on
Logarithmic scale
A numerical progression in which each sequential number represents a consistent multiple of the previous number
Logic
In computers, the execution of basic operations in an organized fashion to accomplish higher level tasks. One example: a computer's ability to combine basic Boolean comparisons like AND, OR, and NOT in various ways allows the machine to do simple mathematical calculations and, under programmed control, make decisions based on the results.
Longitudinal vibration
Periodic motion in which the oscillation moves in the same direction as the sound. Air columns exhibit longitudinal vibration.
Long word
Normally 32 binary digits considered as a unit.
Loop
A piece of material that plays over and over. In a sequencer, a loop repeats a musical phrase. In a sampler, loops are used to allow samples of finite length to be sustained indefinitely.
Loudness
The subjective perception of amplitude.
Low
In digital electronics, the current-off state as opposed to 'high,' meaning current on.
Low pass filter
A filter that attenuates (reduces in level) the frequencies above its cutoff frequency. Low pass filters are used at the input stage of samplers to eliminate frequencies that might cause aliasing and at the output stage to smooth out the stair-stepping inherent in a raw signal coming from a D/C converter.
LSB
Acronym for Least Significant Bit of a byte or Least Significant Byte of a multibyte number. If referring to a byte the LSB is the rightmost bit because it can only represent 1 at most. In a multi-byte number it refers to that byte that holds the least potential value.
LSN
Acronym for Least Significant Nibble. The rightmost four bits of a byte. Those whose places represent the lowest potential number (1's, 2's, 4's, &8's). In MIDI, the LSN of a channel message status byte indicates which of the sixteen basic channels the message is meant for.
LTC
Linear Time Code (also known as longitudinal Time Code) a version of SMPTE timecode that resides on a linear track, such as an audio track or the control track of a videotape.
Main unit
The part of a multi-component computer system that houses the central processor, RAM, ROM, IO ports and other vital hardware. Some computers house one or more peripheral devices like the keyboard or the video monitor in the same case as the main unit.
Mainframe
A large, powerful computer system with many off-site input-output devices called terminals. While usually not as fast in calculating as supercomputers, mainframes are designed to multitask with many users simultaneously and to deal with immense amounts of data. Their RAM is usually in the hundreds of megabytes and their hard disk storage capacity is usually in the gigabyte or terabyte range.
Malleus, Incus, Stapes
Bones of the middle ear also called hammer, anvil, and stirrup. The function of these bones is to transfer mechanical vibrations from the eardrum to the oval window of the inner ear.
Manufacturers message
A MIDI system exclusive message that tag data to specific manufacturers' instruments. All MIDI device manufacturers are assigned their unique numberic tag by the MIDI Manufacturer's Association or the Japanese MIDI Standards Committee (Yamaha = 43H, Sequential Circuits = 01H).
Mapper
A device or part of a software program that translates MIDI data from one form to another in real time.
Masking
The perception of a loud sound making a softer sound inaudible.
Master keyboard
The input device in a MIDI setup that controls all of the other (slave) devices.
Master fader
A straight line variable resistor that controls the output level of many channels simultaneously. In a typical mixer two master faders control the left and right output for all channels.
Math co-processor
An accessory integrated circuit designed to help a central processor with floating point mathematics calculations. It improves the performance of calculation-intensive software like spreadsheets and 3D renderers. Because it is created as a separate circuit it can be optimized for this single function. Although it was once a completely separate chip, more recent central processors have begun to house the math co-processor within the same chip making the separate chip obsolete. (The 486DX CPU is an example of this.)
MB
Acronym for megabyte-- approximately one million bytes or, more precisely 2 to the 20th power or 1,048,576 bytes.
Mb
Acronym for megabits, approximately 1 million bits. Contrast this with MB, one million bytes.
MCI
Media control interface. A multimedia specification designed to provide control of onscreen movies and peripherals like CD-ROM drives.
Meantone temperament
Meatus
The auditory canal leading from the outer ear (pinna) to the eardrum (tympanic membrane).
Meg
Shortened form of mega meaning one million. However when associated with computers and other digital devices that work with binary numbers it actually means 2 to the 20th power (2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2) or 1048576.
Mega
One million. However when associated with computers and other digital devices that work with binary numbers, it actually means 2 to the 20th power (2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2) or 1,048,576.
Megabyte (MB)
Linguistically speaking, a million bytes. In practice, a megabyte often contains 1,024 kilobytes.
Megahertz
A million cycles per second. Frequencies expressed in megaherts most often refer to computer speeds and other electronic data transmissions.
Memory
A system or device for storing information -- in the case of musical devices, information about patches, sequences, waveforms, and so on.
Menu
A list of commands from which the user selects which he wants executed. Different computers and software may use various types of menu interaction (drop-down, pull-down, pop-up, etc.)
Menu strip
A list of command sets that appears at the top edge of the computer screen. Clicking on a word in the menu strip drops down a list of related commands which execute when selected.
Merger
A MIDI accessory that allows two incoming MIDI signals to be combined into one MIDI output.
Message
In MIDI a set of bytes that conveys a specific command.
MFLOP
Acronym referring to Millions of Floating Point Operations Per Second. A measure of a computer's speed in performing fractional (decimal point) math.
MHz
Synonym for Milions of Hertz. (Hertz equates with cycles per second.) The term is commonly used to refer to vibration in the electromagnetic spectrum (computers, radio, television, light and above).
Mic level
A low level voltage about 1/100th the pressure of line level.
Microphone
A transducer whose function is to convert rapid fluctuations in air pressure caused by sound into equivalent fluctuations in electrical energy.
Micro
One millionth-- as in a microfarad (a common measure of electrical charge)
Microcomputer
Usually refers to a desktop sized or smaller computer designed for a single user. The term also now includes notebooks. As computers grow exponentially in power and application, the terms micro, mini, workstation, mainframe, and supercomputer begin to blur.
Microprocessor
An single integrated circuit (chip) that acts as a CPU, that is it can store and retrieve data from memory and perform logical operations on it.
.mid
A common suffix for standard MIDI files saved to a computer's hard drive or floppy disk. A typical standard MIDI file name with the suffix would look like this: MySequence.mid. Suffixing a name when saving a document is good practice. Not only does it serve as an identifier for many programs, it allows the user to see at a glance what type of data the document contains and to sort through hundreds of collected files more easily.
Middle ear
The air filled cavity between the eardrum and the cochlea or inner ear. Bones in the middle ear (the ossicles) conduct vibrations from the eardrum to the oval window on the cochlea.
MIDI
Acronym for Musical Instrument Digital Interface. A set of specifications which details a method for electronic musical instruments and computers to communicate performance commands through numbers.
MIDI accessories
Minor
MIDI beat
MIDI clock
A 1 byte system real time message that advances a receiving sequencer ahead by 1/24th of a quarter note.
MIDI interface
A circuit which translates data between computers and MIDI devices.
MIDI Mapper
A Windows applet that automatically maps (shifts the value of) channel, program change, and note numbers. For example, a map could cause all notes coming in on MIDI channel 3 to go out on MIDI channel 7.
MIDI merge box
An electronic device designed to accept MIDI commands from several sources simultaneously and send them on through a single output. This is more complicated than it may seem at first because while the commands must be kept in sync the bits and bytes which make them cannot be interleaved.
MIDI message
A set of bytes that conveys a meaningful command. MIDI messages can be as short as 1 byte in the case of the system real time clock message or hundreds of bytes long in the case of some manufacturers sysex messages. Most basic messages are 2 to 3 bytes long, and all begin with a status byte.
MIDI mode
Any of the ways of responding to incoming MIDI data. While four modes -- omni off/poly, omni on/poly, omni off/mono, and omni on/mono -- are defined by the MIDI specification, omni on/mono is never used, and at least two other useful modes have been developed -- multi mode for multitimbral instruments and multi-mono for guitar synthesizers.
MIDI Out/Thru
A MIDI output port that can be configured either to transmit MIDI messages generated within the unit (Out) or to retransmit messages received at the MIDI In (Thru).
MIDI patchbay
A unit which connects between several MIDI devices and which allows the user to configure any one as the master and others as slaves without having to change cable connectionsl
MIDI thru
There are two types of MIDI thru. One, a simple hardware connection, is found on the back panels of many synthesizers. The thru jack in this case simply duplicates whatever data is arriving at the MIDI in jack. Sequencers have a second type, called software thru. In this case, data arriving at the in jack is merged with data being played by the sequencer, and both sets of data appear in a single stream at the out (not the thru) jack. A software thru is useful because it allows you to hook a master keyboard to the sequencer's MIDI input and a tone module to its output. You can then play the keyboard and hear the tone module, and the sequencer can also send its messages directly to the tone module.
Midrange
Millisecond (ms)
One one-thousandth (0.001) of a second.
MIME type
MIME is an acronym for Multipurpose Internet Mail Extensions. A group of standard file formats that Web browsers or other programs can be set to recognize and process when they are received over the Internet.
Minicomputer
Usually refers to a powerful computing system disigned for scientific applications or computer aided design. It can be configured as either a single or multi user system and is often applied as a medium size network server. It usually falls in the blurred area between microcomputer and mainframe in speed and capacity.
MIPS
Acronym for Millions of Instructions Per Second. A measurement used to compare the processing speed of various computers. Because there are many variables in real world computer speed (like how many instructions it takes to complete a given task in different computers), MIPS is being replaced by other more revealing measures like SPECmarks.
Mirror
 
Mixer
A device that adds two or more audio signals together. It also normally provides level balancing (preamping for weaker input signals and attenuation for hot signals) and may provide frequency equalization features and signal routing for external processors.
MMA
Acronym for MIDI Manufacturers Association. This is the controlling body for MIDI in the United States.
MMC
The MIDI Machine Control standard, which allows a compatible recording device to either be controlled or to act as a controller when starting, stopping, enabling tracks for record, and so on.
MMU
An acronym for Memory Management Unit. The cpu circuit that translates logical addresses into physical addresses in RAM. It allows virtual memory, and memory protection among other benefits.
MMX
Intel's recent multimedia chip design
Mode
In MIDI a message which tells the receiving instrument how to respond to incoming data. Omni on/off switches the receiver between reacting to messages on any channel and reacting to messages only on one selected channel. Mono/Poly switches the receiver between a one-note-at-a-time instrument like clarinet and a multiple note instrument like a piano. While four modes -- omni off/poly, omni on/poly, omni off/mono, and omni on/mono -- are defined by the MIDI specification, omni on/mono is never used, and at least two other useful modes have been developed -- multi mode for multitimbral instruments and multi-mono for guitar synthesizers.
Modem
A concatenation of the words MOdulate/DEModulate. A device for translating digital computer data into analog form for transmission over telephone lines. Older modems did this by substituting a high tone for 'on" and a low tone for "off." This is known as frequency shift keying or FSK. Newer modems use differential phase shift keying (DPSK) and handshaking to achieve faster rates than FSK is capable of.
Mod files
Common format for self-containded computer music files. They consist of a digital sequence of four (sometimes 8) tracks and one or more digitized sounds for each track.
Modular
Hardware or software that is constructed of individual discrete parts, each of which serves a separate function in the entire process. Modular construction is efficient because the same module can be applied in many different configurations.
Modulate
To send a control signal to a sound source so as to change the character of the sound.
Modulator
In FM synthesis an audio signal that is applied to another (the carrier). This creates many other sideband frequencies, difference tones and summative tones, in addition to the two original signals.
Module
A hardware sound generator with no attached keyboard. A module can be either physically separate or integrated into a modular synthesizer, and is designed to make some particular contribution to the process of generating electronic sound.
Mod wheel
A controller, normally mounted at the left end of the keyboard and played with the left hand, that is used for modulation. It is typically set up to add vibrato. See modulation, vibrato.
Monitor
The video output device attached to a computer. Although it seems similar to a television, a computer monitor's circuitry is usually designed to produce a sharper resolution. It operates at a higher bandwidth, has a tighter dot pitch and gun convergence, and refreshes the image more times per second.
Mono mode
One of the basic reception modes of MIDI devices. In mono mode, an instrument responds monophonically to all notes arriving over a specific MIDI channel.
Monophonic
Capable of producing only one note at a time.
Motherboard
The main printed circuit of any electronic device. In a computer it is most often a green plastic base on which are laid out the bus lines and sockets to connect the central processor, memory chips, input/output ports, accessory slots, etc.
Motorola
Major manufacturer of integrated circuits and other electronic devices. Their families of 680x0 and PowerPC microprocessors are the central processors of Macintoshes as well as many other computers and related devices.
MOTU
Acronym for Mark Of The Unicorn. A major creater of music software and hardware for the Macintosh. Their major sequencing package, Performer, is very popular. as are their advanced MIDI interfaces.
Mount
To make a device appear in the computer's interface. For example an external disk drive must be mounted before it will be visible on the Mac's desktop.
Mouse
A handheld object whose movement across a flat surface is mimicked by a graphical pointer on a computer screen. Most mice operate by allowing a heavy rolling ball to rotate two interior wheels. Their turning feeds pulses to a circuit that interprets them as vertical and horizontal steps. One, two, or three buttons control selection of items in the visual interface. The mouse was invented by Douglas Engelbart of Stanford University in 1968.
MPC
Multimedia Personal Computer. A specification stating the minimum hardware requirements a computer must meet to display the MPC logo. They include 2Mb of RAM, a 16MHz 386SX processor, and 8-bit sound capabilities. This specification was published in 1990, and has since been bettered by the MPC 2 & 3 specs.
MPC 2
Multimedia PC, level 2. This specification requires the same types of hardware as MPC level 1, but with increased power and capacity. For example, 4Mb of RAM, a 25MHz 486SX processor, and 16-bit sound capabilities are specified.
MPC 3
Acronym for Multimedia PC, level 3. This specification requires 8 Mb of RAM, a 75 MHz Pentium class processor, and 16 bit wavetable sound. Almost all computers now meet this spec.
MSDOS
Acronym for Microsoft Disk Operating System. A popular command line interface for Intel based computers. Unable to compete with the ease of use that the Macintosh's graphic user interface exhibited, it has been largely covered by Microsoft's Windows operating system overlay.
MTC
MIDI Time Code. A data format that is used to transmit SMPTE/EBU timecode on a MIDI cable. Essentially this is a method of transmitting absolute timing in hours, minutes, seconds, and frames.
MPC
Acronym for Multimedia Personal Computer. A term and an associated standard created by the software publishers association to assure compatability with computers from many different manufacturers. It suggests minimum requirements for memory, CPU speed, hard drive capacity, CD-ROM, video and sound output.
MSB
Acronym for Most Significant Bit of a byte or the Most Significant Byte In a multi-byte number. In a byte it refers to the leftmost bit (00000000) because that place has the potential to represent the highest number (128). In a multibyte number it refers to the byte that has the potential to represent the highest number (256 x the value shown in the byte).
MSC
Acronym for MIDI Show Control. A 1991 addition to the MIDI spec that allows for the control of lighting and multimedia apparatus like projectors, video, turntables, etc through real time system exclusive.
MSDOS
Acronym for Microsoft Disk Operating System. A popular command line interface for Intel based computers. Unable to compete with the ease of use that the Macintosh's graphic user interface exhibited, it has been largely covered by Microsoft's Windows operating system overlay.
MSN
Acronym for Most Significant Nibble. In an 8 bit byte the MSN is the leftmost four bits. They are Most Significant because they have the potential to represent a higher total (240) than the right four bits which can only reach a total of 15.
MTBF
Acronym for Mean Time Between Failures. An estimated measure of a device's reliability.
MTC
MIDI time code. MTC is a way of transmitting SMPTE timing data over a MIDI cable. See SMPTE time code.
Multimedia
A computer or program that uses sound with animation or video. Many multimedia programs are stored on compact discs because sound and video take up more space than a floppy diskette can hold. Computers must have sound cards and headphones or speakers for sound to be heard.
Multi mode
A MIDI reception mode in which a multitimbral module responds to MIDI input on two or more channels and maintains musical independence between the channels, typically playing a different patch on each channel.
Multisample
The technique of sampling an acoustic source in several (or many) tessituras and then mapping these separate samples to appropriate ranges of a sampler's keyboard. Because most acoustic instruments produce different timbres from low to high range, this technique allows a more realistic sound on playback. In some cases every key is mapped to a different sample.
Multiprocessor
A computer that uses 2 or more central processing units to work on data. Multiprocessing requires that programs be adapted to divide their tasks. Several Macintosh clones offer more than one CPU (for example: DayStar's Genesis); however, their applications have been limited to the few programs that support them. (Adobe offers a special version of PhotoShop that does this.)
Multitimbral
Capable of playing more than one tone color (timbre) at the same time. A typical multitimbral synthesizer can play, for example, clarinet, piano, and percussion parts all at once.
Multitasking
The ability of a computer to work on two or more programs at the same time. This is not actually an ability to divide attention in two but rather the ability to alternate processes in small time slices.
Multitrack
Recording process in which audio sources can be recorded on adjacent sections of tape at different times. The point is to allow the user to listen to one part while laying down another.
NAMM
Acronym for National Association of Music Merchants. A group which promotes the marketing of music related products.
Nano
One billionth. In a nonosecond electricity travels about half a foot.
Natural Harmonic Series
A complex tone comprised of a fundamental pitch and overtones which all bear integer relationships to the fundamental. This is the normal phenomenon created by vibrating strings and columns of air and causes a "musical" tone quality as opposed to the non-integer relationships created by vibrating plates (cymbals, drum heads, bells) which cause a more "clangorous" tone quality.
Natural scale
A progression of frequencies built on the intervals of a natural harmonic series without temperaments.
Navigator
Popular browser software that allows access to the world wide web. Marketed by Netscape corporation.
Netscape
Company (Netscape Communication Corp.) that produces a common world wide web browsers, Netscape Navigator or Communicator
Network
A group of computers and peripherals that are connected by communications facilities. A network can be as small as two computers or as large as the world encompassing Internet. It can involve permanent cables, like those found on local area networks, or temporary connections made through telephone or other communications links.
Newsgroup
A group of messages about a single topic. On the Internet, newsgroups bring together people around the world for discussion of shared interests.
Nibble
One half of an 8 bit byte or in other words 4 bits.
NNTP
Network News Transmission Protocol. Standardi7.ed method for transmitting news from Usenet newsgroups.
Noise
The term actually has two meanings: 1. an audio signal caused by aperiodic (irregular) vibration or 2. any undesirable addition to audio or video.
Non-registered parameter
Normalize
To boost the level of a waveform to its maximum amount short of clipping (distortion).
Notch filter
A circuit designed to reduce the amplitude of a narrow range of frequencies while passing the frequencies on either side unhindered.
Note editor
A computer program designed to output high quality music notation from user input.
Note off
One of seven basic channel messages detailed in the MIDI spec. It consists of 3 bytes. The first, a status byte gives the actual command ("Turn off a note..") and the channel identifier (".. on channel 1...") The second and third bytes, both data bytes, respectively identify which note to turn off ("..middle C..") and how hard to turn it off (".. with maximum velocity.") For traditional keyboardists it may seem unuseful to attach velocity data to turning a note off, but it makes sense: the data can be assigned to many controls-- pitch bend, release speed, etc. which would give the performer extra nuance in his music.
Note on
One of seven basic channel messages detailed in the MIDI spec. It consists of 3 bytes. The first, a status byte gives the actual command ("Turn on a note..") and the channel identifier (".. on channel 1...") The second and third bytes, both data bytes, respectively identify which note to turn on ("..middle C..") and how hard to turn it on (".. with maximum velocity.")
Nyquist frequency (Nyquist theorem)
The highest frequency that can be reproduced accurately when a signal is digitally encoded at a given sample rate. Theoretically, the Nyquist frequency is half of the sampling rate. For example, when a digital recording uses a sampling rate of 44.1kHz, the Nyquist frequency is 22.050kHz. If a signal being sampled contains frequency components that are above the Nyquist limit, false tones called aliases will be introduced in the digital representation of the signal. To avoid these this problem those frequencies are filtered out of the audio chain prior to digital encoding.
OLE
Acronym for Object Linking and Embedding. A Microsoft created standard which allows documents of created in one type of application like a graphics program to be attached to a different type of program like a word processor. OLE allows embedded objects to be changed in the original program and reflect those changes in its host.
Omnidirectional
A microphone pickup pattern that shows equal sensitivity to sound coming in from any angle.
Omni mode
A MIDI reception mode in which a module responds to incoming MIDI channel messages no matter what their channel.
Omni off / on
Two MIDI mode controllers that tell the receiving instrument how to respond to incoming data. Omni off makes the instrument act only on messages which carry the tag matching the channel that it has been set to while Omni on makes it act on messages encoded for any channel
OMS
Open Music System (formerly Opcode MIDI System). A real-time MIDI operating system for Macintosh applications (and slated to be integrated into Windows 95). OMS allows communication between different MIDI programs and hardware, so that, for example, a sequencer could interface with a librarian program to display synthesizer patch names -- rather than just numbers -- in the sequencer's editing windows.
Online Servicc
A commercial network to which individuals can connect their personal computers for data interchange and information gathering. Common features include frequently updated news and weather, e-mail, discussion groups, shopping, and bulletin boards. Examples: America Online, Compuserve, Prodigy, GEnie, MEDLARS, Delphi, BIX.
Opcode
Publisher of music software Vision, Studio Vision, MusicShop, etc. and some hardware.
Open architecture
A computer whose system specifications are made public. This practice allows development of expansion products by other manufacturers thus aiding the machine's long term viability.
Opto-isolator
An electronic component whose function is to transfer binary data without a direct transfer of electricity. It does this by enclosing a light emmitting diode and a light sensitive transistor in the same package. The LED pulses light on/off in reaction to the high/low states of incoming electricity. The light collecting cell reacts to these light pulses by sending out corresponding electrical pulses. The purpose of the opto-isolator is to protect instruments against potentially damaging current overloads.
Organ of Corti
The part of the inner ear that lies adjacent to the basilar membrane. It contains cilia that excite as various regions of the basilar membrane vibrate. These cilia convert the mechanical vibration into electorchemical signals that travel up the auditory nerve to the brain.
Oscillator
An electronic sound source. In an analog synthesizer, oscillators typically produce regularly repeating fluctuations in voltage; that is, they oscillate. In a digital synth, an oscillator more typically plays back a complex waveform by reading the numbers from a wavetable.
Operator
A term used in Yamaha's FM synthesizers to refer to the software equivalent of an oscillator, envelope generator, and envelope-controlled amplifier.
OS
Acronym for Operating System. The basic program that controls a computer's operation. The main part of the operating system, the kernal, must be loaded into memory first in order for any other programs to communicate with the hardware. Other parts of the operating system may be loaded and unloaded as needed.
Ossicles
The three bones (malleus, incus, stapes) of the middle ear that transfer sound vibrations from the eardrum to the oval window on the cochlea.
Out
One of the three MIDI data ports (In, Out, & Thru) defined by the MIDI specification for MIDI compatible devices. The Out port transmits messages created within the device to other devices attached through a MIDI cable. In some cases, as in a computer's MIDI interface, it can be set to retransmit incoming data too thus acting as a thru port also.
Oval window
The part of the inner ear through which the ossicles transmit vibrations.
Overdub
To record additional parts alongside (or merged with) previous tracks. Overdubbing enables "one-man band" productions, as multiple synchronized performances are recorded sequentially.
Overload
Distortion caused by feeding too strong a signal into an electronic input. An example would be attaching a line level output to a mic level input.
Oversampling
The process of inserting calculated averages between measurements during the sampling process. Inserting a single number halfway in time between the two measurements would be called 2x oversampling, but most often more averages are calculated leading to 4x, 8x and higher oversampling. The purpose of oversampling is to smooth out the stairstepping of the signal caused by the sampling process.
Overtone
A whole-number multiple of the fundamental frequency of a tone. The overtones define the harmonic spectrum of a sound. See Fourier analysis, partial.
Packet-Switching
A communication method that uses any transmission channel or line available at a specific instant. It breaks a message into many smaller addressed parts (packets) and sends them via the first available link toward the receiving machine. The receiving machine reassembles the packets into a meaningful message. Routes can be quite circuitous, but at the speed of light, the complexity and distance of the paths are of little consequence.
Pan
An audio or MIDI control that adjusts the apparent location of a sound source in a stereo field.
Parallel
Two or more operations happening at the same time.
Parallel interface
A connection between two pieces of hardware in which separate wires carry all the bits of a byte at the same time. Compare with a serial interface in which bits must be transferred on a single wire in sequential order.
Parameter
A user-adjustable quantity that governs some aspect of a device's performance. Normally, the settings for all of the parameters that make up a synthesizer patch can be changed by the user and stored in memory, but the parameters themselves are defined by the operating system and cannot be altered.
Parametric EQ
EQ is an acronym for equalizer, an electronic circuit designed to raise or lower amplitude of various ranges of the audio spectrum to achieve a desired overall balance of sound for a specific environment. Parametric equalizers are characterized by having a knob to set the exact frequency band desired and another knob to raise or lower its amplitude.
Parity
A communications parameter used to perform an error-checking procedure. Modems must agree on the parity they will use prior to the start of communications. With even parity, the character must have an even number of digital 1s to be deemed error free by the receiving modem. With odd parity, the character must have an odd number of 1s.
Partial
Any single component of a complex tone. Partials include frequencies of both integer and non-integer relationship to the fundamental frequency
Patch
The configuration of hookups and settings that results from the process of patching, and, by extension, the sound that such a configuration creates. Often used to denote a single tone color or the contents of a memory location that contains parameter settings for such a tone color, even on an instrument that requires no physical patching.
Packet
A group of bytes sent over a computer network. In a packet switching technology like the Internet, all communications are broken apart into packets which are transmitted over any physical connection that is instantaneously available. It is much more efficient than traditional circuit switching.
PCM
Pulse code modulation -- a standard method of encoding analog audio signals in digital form.
Peak
The highest point of a signal.
Pentium chip
Perceiver
Percentage quantization
A method of quantization in which notes recorded into a sequencer with uneven rhythms are not shifted all the way to their theoretically perfect timings but instead are shifted part of the way, with the amount of shift being dependent on the user-selected percentage (quantization strength). See quantization.
Performance command
Periodic motion
Peta
A quadrillion or if referring to a binary device or concept actually 10 to the 50th power or 1,125,899,906,842,624
PGA
Phantom power
A DC voltage supplied to a condensor microphone through the microphone cable.
Phase modulation
Phone plug
Type of connector common in musical instrument hookups and consumer level microphones. So named because it was invented by Bell Telephone for its operators. Classified in 1/4 inch, 1/8 inch, and some smaller sizes.
Phono plug
PhotoCD
A CD-ROM format developed by Kodak to store photographic images on CD's. Stores images in several levels of resolution. Many photofinishing services provide this service for customers' film making it an easy method of getting images to computer.
Physical modeling synthesis
A type of sound synthesis performed by computer models of instruments. These models are sets of complex equations that describe the physical properties of an instrument (such as the shape of the bell and the density of the material) and the way a musician interacts with it (blow, pluck, or hit, for example).
Pico
A trillionth-- as in one picosecond.
Pinna
The outer ear. The obvious, external portion of the hearing mechanism that collects sound and funnels it to the auditory canal. The shape of the pinna helps humans locate sound sources in a vertical plane.
Pink noise
Pit
A microscopic depression on a CD-ROM. Pits and the normal surface area called land reflect laser light differently to create the 1's and 0's of binary code.
Pitch
Pitch bend
A shift in a note's pitch, usually in small increments, caused by the movement of a pitch-bend wheel or lever; also, the MIDI data used to create such a shift. See bend.
Pitch rider
Pitch wheel
Plug-in
A software program that acts as an extension to a larger program, adding new features.
PMMU
Acronym for Paged Memory Management Unit, In the Macintosh, the integrated circuit that allows the hard drive to be used as memory.
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Pole
A portion of a filter circuit. The more poles a filter has, the more abrupt its cutoff slope will be. Each pole causes a slope of 6dB per octave; typical filter configurations are two-pole (12dB/oct) and four-pole (24dB/oct). See rolloff slope.
Poly mode
A MIDI reception mode in which a module responds to note messages on only one channel, and plays as many of these notes at a time (polyphonically) as it can.
Polyphonic
Capable of producing more than one note at a time. All synthesizers place a limit on how many voices of polyphony are available. General MIDI-compliant synthesizers are required to provide 24 voices of polyphony. Compare with multitimbral.
Poly pressure
Polyphonic pressure. (Also called key pressure.) A type of MIDI channel message in which each key senses and transmits pressure data independently. Compare with channel pressure.
Port
An electrical connector of some specialized type, e.g., SCSI port, MIDI port, serial port.
Portamento
Postscript
A page description language invented by Adobe corp. It uses plain English to describe formatting, font choice, and graphics to be printed.
Position
Pot
Potentiometer. A device (commonly attached to a knob or slider) used to adjust some aspect of the signal being passed through it, or to send out a control signal corresponding to its position.
POTS
Acronym for Plain Old Telephone Service. The normal analog telecommunications system used for most home and commercial sites.
Power amp
PowerMac
PowerPC
PPP
PPQ
Acronym for Pulses per quarter-note; the usual measure of a sequencer's clock resolution.
Presbycosis
Preamp
Preset
(1) A factory-programmed patch that cannot be altered by the user. (2) Any patch. Note: Some manufacturers make distinctions between presets, programs, and/or patches, each of which may contain a different set of parameters.
Pretrigger
Program change
A MIDI message that causes a synthesizer or other device to switch to a new program (also called preset, patch) contained in its memory.
Protocol
A set of standards that assures that different network products can work together. Any product using a given protocol should work with any other product using the same
Proximity effect
Public-Domain Software
A program that is offered by its owner or developer for public use and is available for copying and distribution free of charge.protocol.
Pulse wave
Pure tone
Pythagoras
Pythagorean comma
The difference between a perfect octave and an octave derived from a circle of perfect fifths.
Pythagorean scale
PZM
Quantize
To force rhythms played at odd times to be "rounded off" to regular rhythmic values.
Quantization noise
One of the types of error introduced into an analog audio signal by encoding it in digital form. The digital equivalent of tape hiss, quantization noise is caused by the small differences between the actual amplitudes of the points being sampled and the bit resolution of the analog-to-digital converter.
Quarter inch plug
Secondary name for a phone plug. Type of connector common in musical instrument hookups and consumer level microphones. So named because it was invented by Bell Telephone for its operators. Phone plugs also come in 1/8 inch, and some smaller sizes.
QuickTime
A software multimedia environment developed by Apple Computer, running on the Macintosh or under Windows. QuickTime enables the creation and playback of QuickTime movies featuring full-motion video, MIDI tracks, Text, and/or 16-bit ADPCM audio.
RAM
Random access memory. RAM is used for storing user-programmed patch parameter settings in synthesizers, and sample waveforms in samplers. A constant source of power (usually a long-lasting battery) is required for RAM to maintain its contents when power is switched off. Compare with ROM.
Ramping
RCA plug
Realaudio
Realmedia
Real time
Occurring at the same time as other, usually human, activities. In real-time sequence recording, timing information is encoded along with the note data by analyzing the timing of the input. In real-time editing, changes in parameter settings can be heard immediately, without the need to play a new note or wait for computational processes to be completed.
Real time message
Reconstruction filter
A lowpass filter on the output of a digital-to-analog converter that smoothes the staircase-like changes in voltage produced by the converter in order to eliminate clock noise from the output.
Reflection
Registered parameter
Release
The portion of an envelope that begins after the key is lifted. See ADSR.
Release velocity
The speed with which a key is raised, and the type of MIDI data used to encode that speed. Release velocity sensing is rare but found on some instruments. It is usually used to control the rate of the release segments of the envelope(s).
Repeaters
Sites along the Internet that regenerate~ or amplify~ a digital signal as it tra~ verses cyberspace~ decreasing the distortions that can weaken a signaL
Relative time
Reset
Resistor
Resolution
The fineness of the divisions into which a sensing or encoding system is divided. The higher the resolution, the more accurate the digital representation of the original signal will be.
Resonance
A function on a filter in which a narrow band of frequencies (the resonant peak) becomes relatively more prominent. If the resonant peak is high enough, the filter will begin to oscillate, producing an audio output even in the absence of input. Filter resonance is also known as emphasis and Q. It is also referred to in some older instruments as regeneration or feedback, because feedback was used in the circuit to produce a resonant peak.
Resonator
Reverb
A type of digital signal processing that produces a continuous wash of echoing sound, simulating an acoustic space such as a concert hall. Reverberation contains the some frequency components as the sound being processed, but no discrete echoes. See echo, DSP.
Reverberation
Reverse logic
Ribbon microphone
Ring modulator
A circuit that accepts two signals as audio inputs and produces their sum and difference tones at its output, but does not pass on the frequencies found in the original signals themselves.
RISC
An acronym for reduced instruction set computer. A CPU design that minimizes the number of internal instructions necessary to complete a processing task thus making the process faster and less power consuming.
RJ~ 11 cable
A standard telephone wire with small plastic jacks that fit into RJ~11 ports called jacks typically located in the wall or floor on the back of a telephone and on the back of a modem card.
Rolloff
The acuity of a filter's cutoff frequency. Rolloff is generally measured in decibels (dB) per octave. A shallow slope, such as 6dB per octave, allows some frequency components beyond the cutoff frequency to be heard, but at a reduced volume. When the rolloff slope is steep (on the order of 24dB per octave), frequency components very close to the cutoff frequency are reduced in volume so much that they fall below the threshold of audibility. See filter, pole.
ROM
Read-only memory. A type of data storage whose contents cannot be altered by the user. An instrument's operating system, and in some cases its waveforms and factory presets, are stored in ROM. Compare with RAM.
Routers
Also called smart links, these network devices read the addresses on data packets and decide how the packets should proceed to their final destination. Routers also take into accoumt how busy a particular network is and can send data onto an alternate route to avoid a traffic jam on the Internet.
RTF
Acronym for Rich Text Format. A standard for including text formatting commands in ASCII text files. Similar to HTML and other mark-up languages, the commands are included in the text in plain English but set off by brackets which cause them to be interpreted rather than printed. RTF is common as a cross platform and cross application standard when it is important to preserve paragraph formatting, font choice, and letter styles.
Rumble
Running status
A part of the MIDI spec that states that a channel message status byte remains in effect until a different status byte is received. It's an effective (and necessary) method of data compression for the rather limited bandwidth of MIDI's 31,250 bps technology.
Sample
A number representing aone measurement made of a physical phenomenon like sound, light, pressure, etc. A digitally recorded representation of a sound. To make a digital recording.
Sample-and-hold
A circuit on an analog synthesizer that, when triggered (usually by a clock pulse), looks at (samples) the voltage at its input and then passes this voltage on to its output unchanged, regardless of what the input voltage does in the meantime (the hold period), until the next trigger is received. In one familiar application, the input was a noise source and the output was connected to oscillator pitch, which caused the pitch to change in a random staircase pattern. The sample-and-hold effect is often emulated by digital synthesizers through an LFO waveshape called "random."
Sampler
An instrument that records and plays back samples, usually by allowing them to be distributed across a keyboard and played back at various pitches.
Sampling
The process of encoding an analog signal in digital form by reading (sampling) its level at precisely spaced intervals of time. See sample, sampling rate.
Sampling rate
The number of samples taken per second. Typical sampling rates vary from 11kHz to 48kHz.
Sawtooth wave
Scale
Scroll arrow
Scroll bar
Scrub
To move backward and forward through an audio waveform under manual control, in order to find a precise point in the wave for editing purposes.
SCSI
Acronym for Small Computer Systems Interface. An ISO standard for connecting peripheral devices like hard drives, CD-ROMs, scanners, etc. to personal computers. Up to 7 devices can be connected to the same SCSI bus and addressed individually. The original SCSI standard allowed a transfer rate of 5 million bytes per second over an 8 bit path. Later versions of SCSI have advanced this rate to as much as 40 million bytes per second by accelerating the rate and multiplying the path size to 16 or 32 channels.
SCSI-2
See SCSI. A set of standards for transferring data between a computer's main unit and peripherals at faster rates. "Fast" SCSI-2 simply accelerates the speed. "Fast and Wide" SCSI-2 adds more transfer lines (16 or 32) to achieve 20 million bytes to 40 million bytes per second.
SDII
Sound Designer II, an audio file format. The native format of Digidesign's Sound Designer II (Macintosh) graphic audio waveform editing program.
SDS
Acronym for the MIDI Sample Dump Standard. SDS is used to transfer digital audio samples from one instrument to another over a MIDI cable.
Search engine
A software program or service designed to search the Internet for matches to desired topics. Examples are Infoseek, Lycos, Excite, and Yahoo,.
Sequence
A set of music performance commands (notes and controller data) stored in a sequencer.
Sequencer
A device or program that records and plays back user-determined sets of music performance commands, usually in the form of MIDI data. Most sequencers also allow the data to be edited in various ways, and stored on disk.
Sequencing
Serial
Serial interface
An electronic connection between two devices in which digital data is transferred one bit after another, rather than several bits at a time. MIDI is a serial interface. Compare with parallel interface.
Server
The main computer in a network, it serves as the central storage area and data router for many connected computers.
Service provider
In Internet terminology, the commercial company that connects personal computers to the Internet via telephone lines. A service provider usually also offers space on its central computer for individuals to collect e-mail and post home pages.
Shareware
software that is sold by individuals or small companies for a nominal fee. Typically buyers download shareware from computer bulletin board systems and try it out before buying and registering it. Registration entitles buyers to users manuals support and discounts on future upgrades.
Shielded, twisted pair
Shockwave
Shotgun
Sidebands
Frequency components outside the natural harmonic series, generally introduced to the tone by using an audio-range wave for modulation.
SIMM
SimpleText
A small program supplied with Macs and many software programs that allows fast access to ReadMe files. Simpletext is designed to replace Apple's older TeachText. It gives many other functions including ability to play Quicktime files, show pictures, and translate MIDI files into Quicktime.
Sine wave
A signal put out by an oscillator in which the voltage or equivalent rises and falls smoothly and symmetrically, following the trigonometric formula for the sine function. Sub-audio sine waves are used to modulate other waveforms to produce vibrato and tremolo. Audio-range sine waves contain only the fundamental frequency, with no overtones, and thus can form the building blocks for more complex sounds.
Sizer
Slave
SLlP-PPP
Serial Line Interface Protocol-Point-To-Point ProtocoL Lets you connect your computer system to the Internet itself, rather than logging on through an Internet access provider's host computer and issuing commands through a shell. SLIP-PPP connections let you communicate directly with other computers on the network using TCP/IP connections.
SM-58
SMPTE timecode
A timecode standard developed by the Society of Motion Picture and Television Engineers and the European Broadcasters Union. (Timecode is a signal that incorporates realtime information (hours, minutes, seconds, and frames).
SMTP
Simple Mail Transfer Protocol. Set of explicit steps that must be used by one Internet computer to connect to another computer to transmit a message to its next stop.
Snail Mail
Slang term used by online users referring to letters and other paper mail sent through the U.S. Postal Service.
SND
Sound resource. A Macintosh audio file format.
SNR
Socket
Software
Programs that computers run. Software has no physical connotation. Floppy disks, books, films and anything else that you can touch are not software; only the coding and ideas they contain are.
Song position pointer (SPP)
A type of MIDI data that tells a device how many sixteenth-notes have passed since the beginning of a song. An SPP message is generally sent in conjunction with a continue message in order to start playback from the middle of a song.
Song select
Sostenuto pedal
A pedal found on the grand piano and mimicked on some synthesizers, with which notes are sustained only if they are already being held on the keyboard at the moment when the pedal is pressed. Compare with sustain pedal.
Soundcard
A circuit board that installs inside a computer (typically an IBM-compatible) adding new sound capabilities. These capabilities can include an FM or wavetable synthesizer and audio inputs and outputs. MIDI inputs and outputs are also normally included.
Sound panel
Spam
Unsolicited and undesireable e-mail sent to large mailing lists.
Spec sheet
Split keyboard
A single keyboard divided electronically to act as if it were two or more separate ones. The output of each note range is routed into a separate signal path in the keyboard's internal sound-producing circuitry, or transmitted over one or more separate MIDI channels. Applications include playing a bass sound with the left hand while playing a piano sound with the right.
Spam
Spectrum
SPL
Square wave
Sqwauker
SSA
Acronym for Serial Storage Architecture. One of several new proposed standards designed to replace SCSI for data transfer. It promises a 40 million byte per second throughput and a potential for up to 160 million bytes per second. Up to 127 devices may be attached to the same SSA bus and addressed individually. The standard allows attached computers to send and receive data simultaneously.
SSL
Acronym for Secure Sockets Layer. A security standard that uses encryption to make Web page content secure so intruders cannot decode it.
Standing wave
Star configuration
Start
Start bit
A binary digit that precedes a byte of data in asynchronous transmission. Its purpose is to signal the receiving machine that another byte should be expected.
Status byte
A MIDI byte that conveys the actual command and thus defines the meaning of the data bytes that follow it. MIDI status bytes always begin with a 1 (hex 8 through F), while data bytes always begin with a 0 (hex 0 through 7).
Step entry
A method of recording events (such as notes) into memory one event at a time. Also called step mode and step-time. Compare with real time.
Stop
Stop Bit
A communications parameter that marks the end of a character. There's usually only one stop bit, though sometimes there can be two.
Striping
The process of recording timecode onto a tape track.
Subjective tone
Subtractive synthesis
The technique of arriving at a desired tone color by filtering a few easily produced complex waveforms. Subtractive synthesis is the type generally used on analog synthesizers. The Commodore 64 computer used subtractive synthesis. Compare with FM synthesis, sampling.
Subwoofer
Successive halving
Summation tone
Superscalar
A cpu design that features more than one pipeline. This allows more than one instruction to be processed at the same time.
Sustain
The third of the four segments in an ADSR envelope. The sustain portion of the envelope begins when the attack and decay portions have run their course, and continues until the key is released. The sustain control is used to determine the level at which the envelope will remain. While the attack, decay, and release controls are rate or time controls, the sustain control is a level control.
Sustain pedal
The electronic equivalent of a piano's damper pedal. In most synthesizers, the sustain pedal latches the envelopes of any currently playing or subsequently played notes at their sustain levels, even if the keys are lifted.
Sustenuto
.swa
Switch controller
Switcher
Synchronization
The process of having two or more devices run at exactly the same speed during playback or record. This is usually accomplished by having one device control the other or having both controlled by a third timing device.
Synchronous
A method of electronic data communication that relies on regularly timed intervals common to both receiving and transmitting machines in order to maintain intelligible meaning. It is potentially faster than asynchronous transmission because it does not require start and stop signalling pulses for every byte, but it is also more expensive to implement.
Sync track
A timing reference signal recorded onto tape. See SMPTE time code, FSK.
Synthesizer
A musical instrument that generates sound electronically and is designed according to certain principles developed by Robert Moog and others in the 1960s. A synthesizer is distinguished from an electronic piano or electronic organ by the fact that its sounds can be programmed by the user, and from a sampler by the fact that the sampler allows the user to make digital recordings of external sound sources.
Sysex
System-common
A type of MIDI data used to control certain aspects of the operation of an entire MIDI setup. System-common messages include song position pointer, song select, tune request, and end-of-system-exclusive.
System exclusive (sysex)
A type of MIDI data that allows messages to be sent over a MIDI cable that will be responded to only by devices of a specific type. Sys-ex data is used most commonly for sending patch parameter data to and from an editor/librarian program.
System folder
System message
System real time
A type of MIDI data that is used for timing reference. Because of its timing-critical nature, a system real-time byte can be inserted into the middle of any multi-byte MIDI message. System real-time messages include MIDI clock, start, stop, continue, active sensing, and system reset.
System reset
T1 line
Tag
TAP
TCP/IP
Transmission Control Protocol - Internet Protocol A language governing communication between all computers on the Internet. TCP/IP is a set of instructions that dictates how packets of information are sent across multiple networks. Also included is a built-in error-checking capability to ensure that data packets arrive at their final destination in the proper order.
Telecommunications
Transfer of voice, data, or video over telephone lines.
Telnet
Concatanation of Telephone Network. A method of obtaining information by logging in to another computer remotely. You may control the remote computer as if it were your own.
Tera
A trillion. However, when referring to digital devices that use binary numbers it really means 2 to the 40th power or 1,099,511,627,776.
Terminal
A remote input/output device for a central mainframe computer. A prime example is the ubiquitous automated teller machine.
Terminal Emulation
A technique in which one computer imitates a dumb terminal while communicating with another computer, such as a mainframe, by using certain software.
THD
Total harmonic distortion. An audio measurement specification used to determine the accuracy with which a device can reproduce an input signal at its output. THD describes the cumulative level of the harmonic overtones that the device being tested adds to an input sine wave. THD+n is a specification that includes both harmonic distortion of the sine wave and nonharmonic noise.
Third party
A company that poduces software or hardware for another company's computer.
Thread
A topic oriented message and its responses. Together, threads form a conversation of sorts as people add responses, or they may start a new message, which, in turn, will have its own responses.
Thru
Thru box
TIFF
Acronym for Tagged Image File Format. A cross-platform graphics standard primarily used for scanned images and photographs.
Timbre
Time code
A type of signal that contains information about location in time. Used for a synchronization reference when synchronizing two or more machines such as sequencers, drum machines, and tape decks.
Title bar
Tone generator
Touch-sensitive
Equipped with a sensing mechanism that responds to variations in key velocity or pressure by sending out a corresponding control signal. See velocity, aftertouch.
Track
One of a number of independent memory areas in a sequencer. By analogy with tape tracks, sequencer tracks are normally longitudinal with respect to time and play back in sync with other tracks.
Transducer
Any device which converts one form of energy into another. A microphone is a transducer because it converts mechanical energy, sound vibrations, into electrical energy. A loudspeaker is a reverse example.
Transform
Transformer
Transmitter
Transient
Any of the non-sustaining, non-periodic frequency components of a sound, usually of brief duration and higher amplitude than the sustaining components, and occurring near the onset of the sound (attack transients).
Transparent GIF
A GIF image without a visible background. The image seems to be floating on the page. Graphics tools let you save GIF images in transparent format.
Transverse wave
Trash icon
Traveling wave
Tremolo
A periodic change in amplitude, usually controlled by an LFO, with a periodicity of less than 20Hz. Compare with vibrato.
Triangle wave
Trigger
Trim
Truncate
Tune request
Tweeter
Twisted pair
Tympanic membrane
UART
Undefined parameter
Unidirectional
Unity gain
Universal sysex
Unix
The text-based operating system that supports the Internet's many applications. Unix operating systems are capable of multitasking (operating two or more programs simultaneously) and multithreading (performing two or more actions simultaneously).
Unregistered parameter
Unzip
Slang for uncompressing a compressed file, usually with the PKUNZIP program from PKWare Inc's PKZIP software.
Upload
To send or transmit a file from one computer to another (usually a server) via a modem.
URL
Universal Resource Locator. A naming, or "addressing," system that helps you locate a site on the World Wide Web. The typical format for a URL is service://host/:port/file path.
USB port
VCA
Voltage-controlled amplifier. A device that responds to a change in voltage at its control input by altering the gain of a signal being passed through it. Also, the digital equivalent of a VCA.
VCF
Voltage-controlled filter. A filter whose cutoff frequency can be changed by altering the amount of voltage being sent to its control input. Also, the digital equivalent of a VCF.
VCO
Voltage-controlled oscillator. An oscillator whose frequency can be changed by altering the amount of voltage being sent to its control input.
Vector
Velocity
A type of MIDI data (range 1 to 127) usually used to indicate how quickly a key was pushed down (attack velocity) or allowed to rise (release velocity). A note-on message with a velocity value of 0 is equivalent to a note-off message.
Velocity sensitivity
A type of touch sensitivity in which the keyboard measures how fast each key is descending. Compare with pressure sensitivity.
Veronico
Very Easy Rodent-Oriented Netwide Index to Computer Archives. A program that lets you search "Gopherspace" by keyword. Once you have entered a keyword, the program comes up with a list of sites that house information on your specified subject. If you don't know which Gopher has the information you need, use Veronica.
VFO
Vibrato
A periodic change in frequency, often controlled by an LFO, with a periodicity of less than 20Hz. Compare with tremolo.
Vibrator
Virtual
Existing only in software.
Virtual RAM
Virus
A rogue computer program created to infect other programs with copies of itself. Viruses may clone themselves and multiply, constantly seeking new hosts. Some viruses are relatively benign, serving more as an annoyance, while others are written to damage programs and alter data.
VITC
Vertical Interval Time Code. Unlike LTC, which is analogous to an audio signal, VITC is stored within the "vertical blanking interval" of the videotape; thus it's embedded as part of the video signal.
Voice
(1) An element of synthesizer circuitry capable of producing a note. The polyphonic capability of a synthesizer is defined by how many voices it has. See polyphony. (2) In Yamaha synthesizers, a patch (sound).
Voice message
Vocoder
Volume
VRAM
Acronym for Video Random Access Memory. RAM chips used to hold a computer's display. The amount of VRAM determines the size of the display and the number of colors it can show.
WAIS
Wide-Area Information Servers. An Internet multimedia search-and retrieval tool offering more than 500 databases. WAIS lets you look through the full text of documents rather than just their indices as with Gopher.
WAN
Watt
.WAV
The Windows audio file format. Typically encountered as FILENAME.WAV.
Waveform
A signal, either sampled (digitally recorded) or periodic, being generated by an oscillator. Also, the graphic representation of this signal, as on a computer screen. Each waveform has its own unique harmonic content. See oscillator.
Wavetable
A set of numbers stored in memory and used to generate a waveform. The wavetable synthesizer typically plays sounds whose digital representations have been stored in a wavetable burned into ROM chips.
Wavetable lookup
The process of reading the numbers in a wavetable (not necessarily in linear order from beginning to end) and sending them to a voice channel.
Wavetable synthesis
A type of tonal synthesis based on combining and manipulating pre-recorded waveforms held in ROM memory. Because it can give a more accurate representation of acoustic instruments, it is currently the most popular type of synthesis for inexpensive synthesizers and sound cards.
Web
Short for World Wide Web
Web Crawler
A program that searches the Internet for topics containing words typed in by the user.
Web Server
A computer that is connected to the Web (usually 24 hours a day) and that has been programmed to provide information such as Web pages to other computers that connect to it over the Internet.
Web TV
Wet
Consisting entirely of processed sound. The output of an effects device is 100% wet when only the output of the processor itself is being heard, with none of the dry (unprocessed) signal. Compare with dry.
Wheel
A controller, normally mounted at the left end of the keyboard and played with the left hand, that is used for pitch-bending or modulation.
White noise
Window
A separate viewing area on a computer screen. It is usually scrollable so that contents that do not fit in the size of the window can be moved into the viewable area. On the Mac's desktop, the window acts as a view of the contents inside a folder. These contents can be shown graphically or textually.
Window burn
Timecode that is superimposed as part of a video image.
Woofer
Word
Usually 16 bits considered as a unit. Since it is really a unit referring to a computers capacity to process data in one chunk, it can represent other numbers like 12 bits or 20 bits. In sampling it is a single number (sample word) that represents the instantaneous amplitude of a sampled sound at a particular moment in time. In 8-bit recording, a sample word contains one byte; in 16-bit recording, each word is a two-byte number.
Workstation
Applied to electronic music, a synthesizer or sampler in which several of the tasks usually associated with electronic music production, such as sequencing, effects processing, rhythm programming, and data storage on disk, can all be performed by components found within a single physical device.
Workstation
In computing, a powerful minicomputer used for scientific work or high end graphics.
World Wide Web
A network~wide menu based program providing hypertext and hypermedia links to other information sources throughout the InterneL
WYSIWIG
Acronym for What You See Is What You Get. The ability of a computer program to show on the monitor an accurate representation of what the printed output will look like. WYSIWYG is a somewhat misleading concept in that no video screen can realistically be expected to show the same resolution a printer would produce.
 XG
XLR
Type of 3 pin plug most often used for balanced microphone and other audio line connections. It's also known as a "cannon" connector.
Xmodem CRC
A network communication protocol that employs a sophisticated error checking method through a 16~bit redundancy check.
Yahoo
A common search engine used to find information on the Internet through keyword searches.
Zero point
Zip
Computer slang for copying and compressing a file usually with PKZIP software from PKWare Inc A compressed file occupies 50% or less disk space than an uncompressed file. A compressed file cannot be used in its compressed form but has to be decompressed,or unzipped, first.
.zip
Zip disk
Zip drive
Zmodem
The most popular file transfer protocol. It is very fast, employs highly reliable error checking, can transmit 8KB blocks of data and multiple file, and is able to restart an aborted or interrupted file transfer. Unlike Xmodem and Ymodem, this protocol continues sending blocks of data until the receiving modem detects an erron.
Zone
A contiguous set of keys on the keyboard. Typically, a single sound or MIDI channel is assigned to a given zone.
Zoom box