Aftertouch - A MIDI control that measures the pressure placed on a key after it is fully depressed. The resultant value can be used to alter the volume, pitch, or timbre of the sound (for example, adding tremolo or vibrato) in real time. Technically, aftertouch is called "channel pressure" since it affects all notes being played on the same MIDI channel. (See "Polyphonic Aftertouch," "Tremolo" and "Vibrato")

Amplitude - The amount of displacement from a zero point. The amplitude of acoustic sounds is a measurement of air pressure displacement, while the amplitude of analog signals is a measurement of voltage increase or decrease.

Analog To Digital Converter (ADC) - A component which samples incoming electrical signal at very short, regular intervals and generates a stream of numbers that are equivalent to the voltage received at each interval. (See "Digital To Analog Converter")

Attack - The speed with which a sound reaches its maximum initial volume. (See "Envelope Generator")

Audible - In the range of human hearing; frequencies between 20 Hz and 20 kHz are said to be audible. (See "Hertz" and "Kilohertz")

Bank - An area of memory within which data is stored. A typical electronic keyboard will contain four or more banks of data, each of which contains dozens of sounds.

Bit - Short for "binary digit"; a number which is either one or zero.

Bit Resolution - The number of bits utilized by a digital recording system. Sixteen bits are required for CD-quality audio.

bpm - Short for "beats per minute," the unit of tempo measurement.

Byte - A group of eight bits. (See "Bit")

Channel - See "MIDI Channel"

Channel Pressure - See "Aftertouch"

Chorus - An effect that periodically shifts the pitch of a sound, having the effect of "spreading" it. (See "Digital Signal Processing" and "Effect")

Combi - In some electronic keyboards, refers to a collection of individual sounds mapped to particular note ranges and/or MIDI channels. (See "Mapping")

CPU (Central Processing Unit) - A computer's central microprocessor, responsible for all system logic and memory organization.

Crossfade - A smooth segue between two sounds.

Default - Sometimes known as the "factory" setting; the value of a parameter that is set when an instrument is initialized or first powered on. (See "Initialization")

Digital - Literally, "using digits". A computer is a typical digital device, which can "think" only in terms of the binary numbers one (on) and zero (off).

Digital Signal Processing (DSP) - Mathematical operations performed upon a digitized signal which have the effect of altering the final audio signal. Typical DSP operations include reverb, delay, flanging, phasing, and chorusing. (See "Reverb")

Digital To Analog Converter (DAC) - A component which receives a continuous digital signal from a storage medium and generates an equivalent voltage for each number received. (See "Analog To Digital Converter")

Drawbar - A special organ slider that adds specific overtones to the sound being produced.

Drum Kit - A special kind of synthesizer voice that contains multiple samples of drum or percussion sounds, with each sound assigned to a different key.

Drum Map - The key assignments within a drum kit. (See "Mapping")

Dynamic Allocation - The method of voice allocation used by many electronic keyboards whereby the most recently played notes are sounded and older notes muted ("robbed") as needed.

Dynamic Range - The difference between the loudest and softest sound in a given situation.

Effect Return - The pathway by which the signal from an effect is routed back to the main output. Raising the effect return level causes the sound to become "wetter"; that is, more of the effect is heard.

Effect Send - The pathway by which a sound is routed to an effect. Raising the effect send level causes more of the "dry" signal to be routed to the effect.

Equalization - The process of raising (boosting) or lowering (attenuating) particular frequency areas (i.e., treble, mid, and bass).

Element - In the jargon of some electronic keyboards, the most basic sound component. (See "Partial")

Envelope Generator (EG) - A set of controls within an electronic keyboard that allow you to alter the volume, timbre, and/or pitch of a sound over time, as it is being played. Typical controls allow you to set the attack time, decay time, sustain level, and release rate. (See "Attack," "Decay," "Sustain" and "Release")

Frequency - The number of wave cycles that occur in a given period of time. The unit of frequency measurement is the Hertz. (See "Hertz" and "Kilohertz")

General MIDI (GM) - A standardized subset of rules within MIDI designed to facilitate cross-instrument compatibility. General MIDI instruments (those that display the "GM" logo) all use the same memory areas for sound storage (i.e., an acoustic piano sound is always stored in the first program slot) and always use MIDI channel 10 for drum parts. GM instruments must be capable of playing at least 16 different sounds simultaneously and must have at least 24-note polyphony.

General Synthesizer (GS) - A extended version of General MIDI created by the Roland Corporation.

Gigabyte - One billion bytes (that is, one thousand megabytes) of data. Sometimes called a "gig."

Global - Refers to parameters which affect the entire device, such as master tuning and MIDI receive mode.

Hertz (Hz) - Unit of frequency measurement denoting one wave per second. (See "Frequency" and "Kilohertz")

Interface - The point at which independent systems interact. An interface can occur between machines (as in the MIDI interface, which allows electronic musical instruments and/or computers to interact) or between man and machine (as in a software user interface, which determines how the user navigates through a program).

Kilobyte - One thousand bytes of data. Sometimes called a "k."

KiloHertz (kHz) - Unit of frequency measurement denoting one thousand waves per second. (See "Frequency" and "Hertz")

Level - See "Volume"

LFO (Low Frequency Oscillator) - A component within an electronic keyboard that sweeps back and forth in a particular shape (waveform) at a very slow rate of speed. Used to create continuous (periodic) change to the volume, pitch, or timbre of a sound.

Local Control - A MIDI message (normally set to "on") that enables an instrument's own keyboard to route control data to its own internal tone generating circuitry. When set to "off," this connection is broken. Local Control "off" is generally used only when recording data into a MIDI sequencer (so that the internal tone generating circuitry responds only to incoming MIDI data and not from the keyboard).

Looping - Playing back data repeatedly.

Low Pass Filter - The most commonly used filter in electronic keyboards. It removes frequencies above a particular cutoff point and allows frequencies below that point to pass through. (See "Filter")

Megabyte - One million bytes of data. Sometimes called a "meg."

Microprocessor - A computer chip that performs mathematical operations.

MIDI - An acronym for the Musical Instrument Digital Interface, a standardized digital "language" that allow electronic musical instruments and computers to communicate with one another.

MIDI Cable - A wire used to carry MIDI data. It has three shielded conductors connected to five-pin DIN plugs at both ends. Generally, MIDI cables should not exceed fifty meters in length.

MIDI Channel - The MIDI specification provides for sixteen channels for the transmission and reception of data. This is equivalent to the system used by television, where each broadcast station transmits over a different channel frequency; your television set must then be set to the same channel to receive the signal. A specific bit (digital number) in the MIDI data stream defines the channel over which the data is being transmitted.MIDI Clock - A special MIDI message that specifies the tempo of a MIDI sequence. 24 MIDI clocks are output during each quarter note. (See "Sequencer" and "Synchronization")

MIDI Connector - A five-pin DIN plug.

MIDI Controller - Any device which outputs MIDI data. There are two basic categories: instrument controllers (i.e. keyboard, drumpad, guitar, or wind controllers) and real-time controllers (physical components typically found on electronic keyboards, such as switches, sliders, wheels, joysticks, ribbons, breath controllers, footswitches, and/or footpedals).

MIDI Expression - A special MIDI message (technically, control change #11) which is used to create relative volume changes (crescendi and decrescendi) of a particular MIDI channel. (See "MIDI Pan" and "MIDI Volume")

MIDI File - See "Standard MIDI File"

MIDI In - A 5-pin DIN connector that receives incoming MIDI data.

MIDI Interface - A hardware device that allows a computer to "speak" the MIDI language and to communicate with other MIDI devices such as electronic musical instruments.

MIDI Out - A 5-pin DIN connector through which outgoing MIDI data is transmitted.

MIDI Pan - A special MIDI message (technically, control change #10) which sets the left-right panning position of a particular MIDI channel. (See "MIDI Expression," "MIDI Volume" and "Panning")

MIDI Port - Physical connector through which MIDI data enters or leaves.

MIDI Software - A computer program which can manipulate, play back, and/or store MIDI data. Common MIDI software applications include sequencing, notation, and patch editing/librarian. (See "Notation Software," "Patch Editor," "Patch Librarian" and "Sequencer")

MIDI Thru - A 5-pin DIN connector through which an exact copy of the incoming MIDI data (arriving at the MIDI In) is transmitted.

MIDI Time Code (MTC) - A special MIDI message similar to SMPTE time code but transmitted over MIDI connections that assigns a unique address to each moment in time (usually each 1/120th of a second). (See "SMPTE Time Code" and "Synchronization")

MIDI Volume - A special MIDI message (technically, control change #7) which sets the overall volume of a particular MIDI channel. (See "MIDI Expression" and "MIDI Pan")

Mixer - A device that blends the audio signals from numerous sources (such as electronic instruments, microphones, tape players, CD players, etc.). Mixers often contain faders that allow you to independently adjust the level and pan position of each instrument. (See "Panning")

Multi - (See "Combi")

Multitimbral - The ability to play back more than one sound simultaneously.

Multitrack - Refers to a device or software component that provides more than two tracks for the storage of information. (See "Track" and "Virtual Track")

Part - In General MIDI instruments, usually refers to a particular MIDI channel. Typically, the volume, panning, effect send level(s) and envelope settings for each part can be set independently; any voice placed into that part then assumes those settings. (See "Effect," "Envelope Generator" and "General MIDI")

Partial - In the jargon of some electronic keyboards, the most basic sound component. (See "Element")

Patch - A collection of data that makes up a particular kind of sound (i.e., a "piano patch" or a "guitar patch")

Patch Editor - A computer program that allows sound data in an electronic keyboard to be altered.

Patch Librarian - A computer program that allows sound data in an electronic keyboard to be stored.

Pitch Bend - A means by which the pitch of a sound is altered upwards or downwards. This is equivalent to the act of physically bending a guitar string, hence the name. There is also a special MIDI control message of the same name.

Platform - The type of computer being used for a particular program.

Polyphonic Aftertouch - A special kind of aftertouch that affects individual notes. For example, by pressing down harder on the highest note in a chord, its pitch can be bent without any of the other notes affected. Technically, called Key Pressure. (See "Aftertouch," "Pitch Bend," "Tremolo" and "Vibrato")

Polyphony - The number of notes that can be played simultaneously.

Preset - A factory-configured sound.

Program - (See "Combi")

Program Change - A special MIDI message used to select different sounds over specific MIDI channels.

Punch-In Recording - Recording a specific section of music over a previously recorded track, as opposed to recording continuously from beginning to end. The punch-in point is the moment at which the new recording begins and the old track starts being erased. The punch-out point is the moment at which the new recording ends and the old track stops being erased. (See "Track")

Registration - In organs, a combination of stops selected for use in playing a piece. Sometimes refers to the act of selecting and adjusting organ stops. (See "Stop")

Release - The speed with which a sound returns to zero volume after its key is released. (See "Envelope")

Reverb - Short for "reverberation." A type of signal processing that adds spaciousness and ambience to a sound. (See "Digital Signal Processing" and "Effect")

ROM (Read Only Memory) - A type of high-speed memory whose data cannot be edited but which does not require a constant electrical supply in order to store data. (See "RAM")

Sampler - An electronic music instrument that supports the recording and playback of digital samples.

Sampling Rate - The frequency with which an analog-to-digital converter scans an incoming electrical signal. Higher sampling rates yield greater audio fidelity but require more storage capacity. The four most commonly used sampling rates are: 44.1 kHz (used in CDs); 48 kHz (used by professional DAT recorders); 32 kHz (used by consumer DAT recorders and for broadcast); and 22.05 kHz (used for broadcast and multimedia purposes). (See "Analog To Digital Converter," "CD," and "DAT")

SCSI - An acronym for Small Computer Systems Interface. A high-speed data transfer protocol that is used by many computer systems to interconnect hard drives, CD-ROM drives, and other peripheral devices. All Apple Macintosh computers (except a few very early models) have built-in SCSI ports; Windows computers can also utilize SCSI with the addition of special cards or converters.

Sequencer - A dedicated device or computer application (usually called a sequencer) which records and plays back MIDI data in correlation with a running clock. In effect, a sequencer is a tapeless tape recorder; however, because it is MIDI data (usually all kinds of channel messages) instead of actual audio signal which is stored, there is much greater editing capability, with no potential for signal degradation. Many electronic keyboards have onboard sequencers for use in live performance.

Serial - A type of computer interface where all data is sent down a single wire, one bit at a time. Examples of serial interfaces include: MIDI; the COM ports on a Windows computer (RS-232C); and both the modem and printer ports on a Macintosh computer (RS-422).

Serial Port - The physical computer connection through which serial data enters and leaves.

Signal Processing - See "Digital Signal Processing"

SMPTE Time Code - A standard adopted by the Society of Motion Picture and Television Engineers in which each moment of time (usually, each 120th of a second) is given a unique address. Used extensively in the film and video industries, the main function of SMPTE time code is to synchronize audio and visual cues with one another. (See "MIDI Time Code" and "Synchronization")

Song Position Pointer - A special MIDI message that describes a particular position in a song within a resolution of a sixteenth note. (See "Synchronization")

Song Select - A special MIDI message that instructs a sequencer to load one of several songs stored in its memory. (See "Sequencer")

Sound Card - A board placed in an IBM-compatible computer expansion slot which typically adds a MIDI interface, an internal tone generator, and the ability to record and play back samples of digital audio signal.

Standard MIDI File (SMF) - A standardized file format for MIDI sequence data. Type 1 SMFs are multitrack, multichannel format, while Type 0 SMFs place all the data onto a single multichannel track. SMFs intended for playback on Windows computers are usually given the file suffix ".MID"; SMFs intended for playback on Macintosh computers are normally given the file type "Midi". (See "Sequencer")

Stop - In organs, a tuned set of pipes or digital circuitry emulating a tuned set of pipes. Also refers to the knob, key, or pull that regulates those pipes or circuitry. (See "Registration")

Sustain - The level at which a sound is maintained as long as its key or sustain pedal is being held down. (See "Envelope")

Synchronization - Refers to the procedure by which different devices can operate at the same precise timing.

Synthesizer - An electronic musical instrument which produces audio signal either by the direct manipulation of electrical signal ("analog") or by using mathematical functions to alter a stream of numbers ("digital"). Most modern synthesizers are digital and use wavetable synthesis as their means of generating sounds. (See "Analog," "Digital" and "Wavetable Synthesis")

Tone Module - Typically refers to a keyboardless electronic musical instrument that plays sounds in response to incoming MIDI messages from a keyboard or from a sequencer. (See "Sequencer")

Track - A place for the storage of audio information. Analog tape recorders provide one or more physical tape tracks, while MIDI sequencers and digital audio software interfaces provide one or more areas of memory in which data is stored. (See "Multitrack" and "Virtual Track")

Transducer - A device which converts one form of energy into another. Examples include the microphone (which converts air pressure changes into analog electrical signal) and the loudspeaker (which converts analog electrical signal into the movement of air). (See "Analog")

Transient - A brief, high-amplitude burst of sound.

Tremolo - The periodic alteration of a sound's pitch, usually applied by an LFO. (See "LFO")

Velocity Switch - A process whereby two or more sounds are assigned to the same key, but only one sound is played at any time, depending on the velocity of the keystroke.

Vibrato - The periodic alteration of a sound's volume, usually applied by an LFO. (See "LFO")

Voice - Refers to a note being played. In the jargon of some electronic keyboards, a patch or program. (See "Patch," "Polyhony" and "Program")

Volume - The relative loudness of a sound or a component within a sound.

Wavetable - A series of numbers stored in memory that, when routed to a Digital-to-Analog converter, reconstruct a particular waveform. Wavetables can also be used to reconstruct samples of acoustic sounds.

Wavetable Synthesis - A memory-efficient synthesis technique that produces sounds by rea
ding back stored wavetables at different speeds, depending upon the note being played (higher notes result in higher-speed playback). (See "Wavetable")

Workstation - Typically refers to a multitimbral electronic keyboard that contains drum sounds as well as standard melody sounds and has an onboard sequencer and one or more onboard effects. (See "Effects," "Multitimbral" and "Sequencer")