Glossary of Computer Music Terms

Additive Synthesis
The process of constructing a complex sound using a series of fundamental frequencies (pure tones or sine waves). Each of the fundamental frequencies usually has its own amplitude envelope which allows independent control of each partial (harmonic). Pipe organs or Hammond organs are both instruments which are based on additive synthesis.

Abbreviation for Attack, Decay, Sustain, and Release. These are the four parameters found on a basic synthesizer envelope generator. An envelope generator is sometimes called a transient generator. The Attack, Decay, and Release parameters are rate or time controls. Sustain is a level. When a key is pressed, the envelope generator will begin to rise to its full level at the rate set by the attack parameter, upon reaching peak level it will begin to fall at the rate set by the decay parameter to the level set by the sustain control. The envelope will remain at the sustain level as long as the key is held down. Whenever a key is released, it will return to zero at the rate set by the release parameter.

After Touch
See Pressure Sensitivity

Aliasing is the term used to describe the unwanted frequencies which are produced when a sound is sampled at a rate which is less than twice the frequency of the highest frequency component in the sound. These unwanted frequencies are typically high frequency tweets and whistles. E-mu sampling technology is designed to virtually eliminate audible aliasing.

A device which increases the level of a signal.

Amplitude is a term used to describe the amount of a signal. It can relate to volume in an audio signal or the amount of voltage in an electrical signal.

Amplitude Modulation
A change in the level of a signal. For example, if a Voltage Controlled Amplifier (VCA) were being modulated by a Low Frequency Oscillator (LFO), the result would be a periodic increase and decrease in the audio level of the signal. In musical terms this would be referred to as Tremolo. The abbreviation of Amplitude Modulation is AM.

Data (signal) presented in a non-digital, continuous form.

Analog Synthesizer
A synthesizer which uses voltage controlled analog modules to synthesize sound. The concept of a variety of analog modules all of which can interconnect via a standardized voltage control system was invented by Dr. Robert Moog. The three main voltage controlled modules in an analog synthesizer are: Voltage Controlled Oscillator (VCO), Voltage Controlled Filter (VCF), and Voltage Controlled Amplifier (VCA).

Aperiodic Waveform
A waveform that does not have a repeating pattern.

A device or computer program that sequentially moves a pattern of notes over a range of the keyboard. The speed of the Arpeggiation is variable and the pattern can usually be varied depending on the order or relationship of the notes pressed.

The first parameter of an envelope generator which determines the rate or time it will take for the event to reach the highest level before starting to decay.

Attenuate means to reduce in force, value or amount. An Attenuator is a device that reduces the value of something, usually the amplitude of a signal.

Audible Range
The range of frequencies that the human ear can hear. A healthy young human can usually hear from 20 cycles per second to around 20,000 cycles per second (20-20,000 Hz), less after prolonged exposure to Heavy Metal music or Opera.

Auto Correlation
A process that determines optimum start and ending loop points to produce minimum discontinuity.

Band Pass Filter
A filter which allows only a selected band of frequencies to pass through while rejecting all other frequencies above and below the cutoff point. Usually a bandpass filter will allow the user to set the width of the passband.

The Bank is one name a manufacturer can give to the area that contains all preset, sample data, sequence data and like data in the synth. The Bank does not include information stored on disk.General MIDI banks are how the sounds are stored in a defined way using controller #0 or 32 or both followed by a patch number, ie JV80 using controller 0 value 80 and then a patch to call up a sound stored in it's A Bank.

Baud Rate
The speed at which digital information is passed through a serial interface expressed in bits-per-second. MIDI data is transmitted at 31.25 KBaud or 31,250 bits per second.

Of or based on the number two or the binary numeration system (base 2). Digital computers use this form of numbering because the values of 0 and 1 can easily be represented by an open or closed switch.

A Bit is a single piece of information assigned a value of 0 or 1 as used in a digital computer. Computers use digital words which are combinations of bits. A Byte is a digital word consisting of eight Bits. Most samplers uses a 16 bit number to represent a sound word. A 16 bit word can represent 65,536 different numbers.

Starting up a computer by loading a program that allows it to run other programs. The term comes from bootstrapping which means that the computer "pulls itself up by its own bootstraps."

When recording or sequencing, to bounce tracks means to combine (mix) several tracks together and record them on another track.

An area of computer memory that is used to temporarily store data.

An error in a computer program that causes it to work incorrectly. Very annoying and sometimes not easily fixed either for technical or marketing reasons (A new version is coming out shortly or the program is no longer supported,etc).

A computer word made up of eight bits of data.

(kar' de-oid') A directional microphone with a heart shaped, narrow pattern, which picks up from directly in front of the mic. Very useful for recording drums.

A list of all files stored on a disk or in a bank. Sometimes called a directory or volume or listing,etc.

Unit of pitch equal to 1/100 of a semitone.

Center Detent
A notch in the center of a modulation wheel or lever which allows the performer to find the home position.

Channel, Output
The circuitry through which an instrument outputs individual notes. Can be polyphonic.

Channel, MIDI
An information pathway through which MIDI information is sent. MIDI provides for 16 available channels, each channel usually addresses one MIDI instrument but can address more MIDI instruments, dependent on cabling and setup of the system. Multi channel instruments can recieve several channels at once, see Multitimbral.

Channel, MIDI Control
A MIDI Channel also contains information about which controllers are being varied. Assigning an synth's realtime control destination A or B lets another MIDI device's controllers control the the synth's realtime control destination via the MIDI Control Channels.

An integrated circuit.

A voice doubling effect created by layering two identical sounds with a slight delay (20-50 mS) and slightly modulating the frequency of one or both of the sounds .

A steady pulse from a generator which is used for synchronizing sequencers, drum machines, etc. Common sequencer timing clock rates are 24, 48, 96,120,240,384,or 480 pulses-per-quarter note. MIDI timing clocks run at a rate of 24 ppqn. Also called the resolution, PPQ, ticks, etc of a sequencer, ie Logic Audio uses 980 pulses-per-quarter note to control timing of MIDI events.

A temporary holding place in RAM for what you last cut or copied.

Close Miking
A microphone placement technique which involves placing a microphone close to the sound source in order to pick up mainly direct sound, and avoid picking up reverberant sound.

Computer Interface
Hardware which enables a computer to communicate with other devices. A computer actually uses a lot of interfaces, IDE, SCSI, Modems, Video, etc are all interfaces. A MIDI interface allows a computer to communicate with a musical instrument. It can take the form of a dedicated card or external box or be part of a multi I/O card like a SoundBlaster compatible game card.

Condenser Mike
A microphone which converts sound pressure level variations into variations in capacitance using an electromagnet rather than a fixed or permanent magnet and then into electrical voltage. Using an electromagnet gains better fidelity but requires power in the form of a battery or Phantom Power.

See Envelope Generator

To make a copy of something, by selecting it and choosing the copy function from a menu. What is copied is placed on the clipboard.

Abbreviation for Central Processing Unit. The main component in a computer's microprocessor which performs calculations and executes instructions.

To gradually fade out one sound while fading in another so that a seamless transition is made between the two sounds.

Foiled again. A visual indicator showing the position of the next entry.

To remove something, by selecting it and choosing the cut function from a menu. What you cut is placed on the clipboard.

Cutoff Frequency
The frequency above which a filter will start attenuating signals present at its input. Abbreviated Fc. In most synths it refers to the low pass filter but can be others like a high pass filter.

Information a computer needs in order to make decisions or carry out a particular action.

The unit typically used to indicate the slope of a filter, or how fast the frequency response rolls off past the cutoff frequency. Example: A 24 dB/octave filter would attenuate an input signal by 24 dB one octave above the cutoff frequency, by 48 dB two octaves above the cutoff frequency, and so on.

The second stage in an ADSR type envelope generator. See ADSR.

Decibel (dB)
A reference for the measurement of sound energy. The minimum change in volume that the human ear can perceive. Named after Alexander Graham Bell. A decibel is 1/10th of a Bel.

A controllable time parameter giving the ability to start an event only after a predetermined amount of time. Most commonly used in an efx device to add and control repeats of an audio signal with decaying levels of volume.

The amount of modulation. Sometimes called Amount, Width, Intensity or Modulation Index.

Equipment that uses quantities represented as binary numbers. In a digital synthesizer every aspect of the sound generation is handled as a numeric calculation. The digital information is not audible and so must be converted to analog form by a DAC before it is output.

Digital to Analog Converter (DAC)
A device which interprets Digital information and converts it to Analog form. All digital musical instruments must have a DAC so that we can hear their output.

A device that gives information in a visual form. A computer monitor is a display as is those tiny little LCDs on MIDI keyboards.

Distant Miking
A microphone placement technique which involves placing a microphone far from the sound source in order to pick up a high proportion of reverberant sound.

Dynamic Allocation
Dynamic Allocation defeats any pre-assigned output channel assignments and assigns the output channels according to a modified circular algorithm. (Used to assign any available voice to whatever sound that needs to be played at that time.)

Dynamic Mike
A microphone in which the diaphragm moves a coil suspended in a permament magnetic field in order to generate an output voltage proportional to the sound pressure level. Using a permament magnet does not need power so no battery or other source is needed.

Dynamic Range
The range of the softest to the loudest sound that can be produced by an instrument. Or the range of the low and high signal levels obtainable by a velocity sensitive keyboard. The greater the Dynamic Range, the more sensitive the keyboard.

To change or modify information. To change parameters or alter existing data.

Envelope Generator
A circuit, usually triggered by pressing a key on a keyboard, that generates a changing voltage with respect to time. This voltage typically controls a VCF or VCA. An AHDSR, ADSR, TVA are types of Envelope Generators. See ADSR.

Equal Temperament
A Scaling system where the octave is divided into 12 equal parts. The ratio of the frequencies between any two adjacent notes is exactly the same. Most keyboard instruments are scaled in this manner. Some keyboards can be tuned to other relationships by the use of the tuning function built into them by the manufacturer.

A device which allows attenuation or emphasis of selected frequencies in the audio spectrum. Equalizers usually contain many bands to allow the user a fine degree of frequency control over the sound. Common are 10, 12, 31 bands either stereo or mono depending on use.

Error Message
A message shown in the display to alert the user that an error of some type has occurred. Usually can only be understood programmers or tech support people.

Fast Fourier Transform
A computer algorithm which derives the fourier spectrum from a sound file.

See Cutoff Frequency

A device used to remove unwanted frequencies from an audio signal thus altering its harmonic structure. Low Pass filters are the most common type of filter found on music synthesizers. They only allow frequencies below the cutoff frequency to pass (Low Pass). High Pass filters only allow the high frequencies to pass, and Band Pass filters only allow frequencies in a selected band to pass through. A Notch filter rejects frequencies that fall within its notch.

An effect created by layering two identical sounds with a slight delay (1- 20 mS) and slightly modulating the delay of one or both of the sounds. The term comes from the early days of tape recording when delay effects were created by grabbing the flanges of the tape reels to change the tape speed.

Floppy Disk
A thin portable disk used to store digital data.

Fourier Spectrum
The description of a sound that is in terms of its distribution of energy versus frequency rather than its amplitude versus time (waveform).

The number of cycles of a waveform occurring in a second.

Frequency Modulation
The encoding of a carrier wave by variation of its frequency in accordance with an input signal.

Frequency Shift Keying. An audio tone (frequency) modulated by a square wave, which is used both for data transfer and also for sequencer and drum machine synchronization.

The first, lowest note of a harmonic series. The Fundamental frequency determines a sound's overall pitch.

The factor by which a device increases the amplitude of a signal. Negative gain will result in the attenuation of a signal.

A rapid slide through a series of consecutive tones in a scale like passage. When two notes are played with glissando on, every note in between the two notes will be played in a sequential order. Similar to portamento except that the pitch changes in semitone steps.

Ground Loop
Hum caused by currents circulating through the ground side of a piece of equipment or system. This is due to grounding it at points of different voltage potential.

Hard Disk
A storage medium for digital data which can hold more information and access it faster than a floppy disk.

Harmonic Distortion
The presence of harmonics in the output signal of a device which were not present in the input signal.

A unit of frequency equal to 1 cycle per second. Named after Heinrich R. Hertz.

High Pass Filter
See Filter

To prepare a disk to receive data. A hard disk or a floppy disk must be initialized before it can be accessed.

The amount of modulation.

Just Intonation
A system of tuning in which the distances between pitches are based on the natural harmonic series instead of the octave being equally divided.

Abbreviation for Kilo or 1000

Keyboard Assignment
The assignment of specific sounds to an area of the keyboard. For example, the lowest octave could be drum sounds, the next octave could be an electric bass, the rest of the keyboard could have various piano samples assigned to it. Also called Key Groups.

The ability to place or stack two or more sounds on the same area of the keyboard to create a denser sound.

Low Frequency Oscillator. An oscillator used for modulation whose range is below the audible range (20 Hz). Example: Varying pitch cyclically produces vibrato.

To transfer from one data storage medium to another. This is generally from disk to RAM memory or vice-versa, as opposed to saving from RAM to disk.

To prevent data from being edited, discarded or renamed, or to prevent entire banks or disks from being altered.

Looping is the process of repeating a portion of a sample over and over in order to create a sustaining sound. The looped sound will continue as long as the key is depressed. A sound is usually looped during a point in its evolution where the harmonics and amplitude are relatively static in order to avoid pops and glitches in the sound.

Low Note Priority
When more than one note is played on a monophonic synthesizer, only the lowest note will sound.

Low Pass Filter
A filter whose frequency response remains flat up to a certain frequency, then rolls off (attenuates signals appearing at its input) above this point.

The part of a computer responsible for storing data.

To combine or unite. To Merge means to combine sequences, sounds, tracks, MIDI data, etc.

Acronym for Musical Instrument Digital Interface. MIDI enables synthesizers, sequencers, computers, rhythm machines, etc. to be interconnected through a standard interface. MIDI is an asynchronous, serial interface, which is transmitted at the rate of 31.25 KBaud or 31,250 bits per second.

MIDI Clock
Allows instruments interconnected via MIDI to be synchronized. The MIDI Clock runs at a rate of 24 pulses-per-quarter-note.

MIDI Continuous Controller
Allows continuously changing information such as pitch wheel or breath controller information to be passed over the MIDI line. Continuous controllers use large amounts of memory when recorded into a MIDI sequencer. Some standard MIDI Continuous Controller numbers are listed below.

PWH = Pitch Wheel
CHP = Pressure
0 = GM Bank select
1 = Modulation Wheel
2 = Breath Controller
3 = (Pressure on Rev. 1 DX7)
4 = Foot Pedal
5 = Portamento Time
6 = Data Entry
7 = Volume
8 = Balance
10 = Pan
11 = Expression Controller
16-19 = General purpose controllers 1-4 (High Res.)
32 = Bank Select for some MIDI devices like Korg, Yamaha, ect
64 = Sustain Switch (on/off)
65 = Portamento Switch (on/off)
66 = Sustenuto (chord hold)
67 = Soft Pedal (on/off)
69 = Hold Pedal 2 (on/off)
80-83 = General purpose controllers 5-8 (Low Res.)
91 = External Effects Depth
92 = Tremolo Depth
93 = Chorus Depth
94 = Detune
95 = Phaser Depth
96 = Data Increment
97 = Data Decrement

The process of one audio or control voltage source influencing a sound processor or other control voltage source. Example: Slowly modulating pitch cyclically produces vibrato. Modulating a filter cyclically produces wa-wa effects.

Modulation Index
The depth of modulation when performing frequency modulation.

Module Identifier
The screen that displays information about what module is currently activated.

A musical instrument that is only capable of playing one note at a time. Music with only one voice part.

The ability of a musical instrument to produce two or more different sounds or timbres at the same time. May or maynot respond to mutli MIDI channels. A sampler can play several sounds at once but may only respond to one MIDI channel ie: Ensoniq's Mirage sampler.

A way to record a complex musical piece by dividing it into simple tracks, and combining the tracks during playback. Can be a MIDI sequencer, analog tape machine or digital recorder with 4 or more tracks.

A digital processing function that increases the amplitude of a sound file until the peak amplitude of its loudest sample reaches 100% of full scale or a slightly lower level like 99% so additional digital processing can be done without adding distortion.

Distortion which is caused by exceeding the dynamic range of a circuit.

Short for Panorama. To create a stereo effect between two speakers, you can pan a sound between them see Panning.

To move an audio signal from one output to the other. Panning a sound between two speakers changes the apparent position of the sound.

Parallel Interface
A computer interface in which data is passed simultaneously over many wires. A Parallel Interface is usually much faster than a serial interface. The SCSI Interface on the Emulator III is an example of a Parallel Interface.

To put a copy of the contents of the clipboard (whatever was last copied or cut) in at the specified insertion point.

Referring to a particular sound created on a synthesizer. Comes from the use of patch cords on the original modular synthesizers. Other names for it are Voice, Instrument, Single, Multi, Combination, Program, Performance, Preset, etc.

A musical instrument that is able to play more than one note at the same time. Music with more than one voice part.

A preprogrammed sound and control setup on a sampler or synthesizer. Presets can be made up in advance of a performance, stored in memory, then recalled instantly when desired. See Patch.

Pressure Sensitivity
The ability of an instrument to respond to pressure applied to the keyboard after the initial depression of a key. Sometimes called aftertouch. As a MIDI controller it comes in two types: Polyphonic (Key) aftertouch where each key has its own sensor or Monophonic (Channel) aftertouch where any key will affect all keys that are currently played. Whether or not a keyboard has either one and what you can do with them is designed into them by the manufacturer.

Proximity Effect
When cartioid microphones are placed very close to the sound source, a boosting of the bass frequencies occurs which is known as the proximity effect.

When recording, punching in over-writes a previously recorded track starting at the punch in point. In digital audio or MIDI recording you may the option to keep the previously recorded track as a seperate file or region depending the software or device. For example, Logic Audio gives you such an option.

When recording, punching out stops the recording process started by a punch in, thus preserving the previously recorded track starting at the punch out point.

The figure expressing a filter's resonance. Varying Q varies the sharpness of the filter sound. Also called just resonance or res.

A function on some sequencers which modifies the information in its memory to improve the rhythmic accuracy and correct playing errors.

Acronym for Random Access Memory. The memory in a computer in a computer that stores data temporarily while you are working on it. Data stored in RAM is lost forever when power is interupted to the machine if it has not been saved to another medium, such as floppy or hard disk

RS 422
A high-speed serial communication port which allows data to be transferred to and from an external computer at a very high rate (500K baud).

Realtime Controls
Occurring in actual time or live.

A frequency at which a material object will vibrate. In a filter with resonance, a signal will be accentuated at the cutoff frequency. See Q.

Retarding. A direction to slow down gradually.

Sample Rate
When digitally sampling a signal, the rate at which level measurements of the signal are taken. Usual sample rates are 32, 44.1 or 48.

The process of recording a sound into digital memory. Usually referred to recording the sound into RAM not on to a hard drive or tape. You sample into a sampler like the Roland S760 but record into your program like Logic Audio.

Acronym for Small Computer Systems Interface. An industry standard interface that provides high-speed access to peripheral devices such as hard disk drives, optical discs, WORM drives, etc.

The port on the back of the sampler or computer like a Mac to which SCSI devices are connected.

A device which steps through a series of events. A digital sequencer may record keyboard data, program changes, or realtime modulation data to be played back later much like a tape recorder or player piano. Digital sequencers use memory on the basis of events (key on, key off, etc.) while a tape recorder uses memory (tape) on the basis of time.

Serial Interface
A computer interface in which data is passed over a single line, one bit at a time. The MIDI interface is an example of a serial interface.

Signal Processing
The art of modifying an existing sound through the use of electronic circuitry. The circuit can be analog or digital ie a Roland Space Echo is analog while a Zoom 1204 is digital.

Acronym for Society of Motion Picture and Television Engineers who adopted a standard time code in order to synchronize video and audio. SMPTE information is in the form of Hours, Minutes, Seconds, and Frames. There are two types of SMPTE time code, Longitudinal Time Code which can be recorded on audio tape, and Vertical Interval Time Code which is recorded on video tape. There are 6 types of Frame Rates for SMPTE: 24fps (frames per second) for film; 25fps for PAL video; 29.97 for NTSC video (US Broadcast); 29.97dp (Drop frame)fps; 30fps and 30dp fps.Most music studios use 30fps.

The programs or sets of instructions describing the tasks to be performed by a computer including the one inside digital keyboards, efx processors, etc.

Song Pointer
MIDI information which allows equipment to remain in sync even if the master device has been fast forwarded. MIDI Song Pointer (sometimes called MIDI Song Position Pointer) is an internal register (in the sequencer or autolocator) which holds the number of MIDI beats since the start of the song.

Step Time
A sequencer mode where events are entered one at a time with the user setting the parimeters like pitch, duration and position.

Subtractive Synthesis
The process of constructing a sound by starting with a complex sound and then removing harmonics with a filter. A low pass filter is most commonly used. The cutoff frequency of the filter is usually dynamically varied, which changes the harmonics that are removed. Using the low pass filter on a synthesizer to alter the sound is a form of subtractive synthesis.

An Emulator III MIDI function designed to enhance the Sequencer/MIDI interface. It maps data occurring on a specific MIDI channel to a specific preset within the bank. Similar to standard MIDI Omni Off/Mono mode, but more flexible. Each channel can contain polyphonic note data.

System Exclusive
Midi Data that is used to transfer the programming of a MIDI device to another MIDI device of the same type or into a program on a computer. By using SyEx (system exclusive) you can program from a computer (or similar device ie: Peavey PC1600) any MIDI device in real time or use the computer (or similar device ie: Peavey MIDI Librarian) to store a library of sounds. SyEx is not the sounds or the samples of a device just the parameters settings of it.

A digital signal processing function that fades a sound in or out between two points. Tapering permanently modifies a sound. Also known as Fade In or Out.

Terminating Resistors
Also called a terminator. A group of resistors that should be placed on the SCSI cable before the last device on a SCSI chain. Usually the terminating resistor is built inside the SCSI device. There should be no more than two terminators in a SCSI chain: one at the start, built into the sampler or computer, and one at the end.

Tone color. The quality of a sound that distinguishes it from other sounds with the same pitch and volume. Also used by Roland to describe a sound used in their part mode in the U series synths.

A cyclic change in amplitude, usually in the range of 7 to 14 Hz. Usually achieved by routing a LFO (low frequency oscillator) to a VCA (voltage controlled amplifier).

When manipulating a sample, truncation shortens a sample's length by trimming off parts of the beginning and/or end.

Stands for Time Variant Ampliflier. It is a ampliflier that can change over time. It is used by Roland in the same way others use an VCA (See VCA) to control a synth's output with an envelope. Roland calls it this because there are four levels/four times in their envelope generator instead of an ADSR. Also see envelope generator.

Stands for Time Variant Filter. It is a filter that can change over time. It is used by Roland in the same way others use an VCF (See VCF) to control a synth's output with an envelope. Roland calls it this because there are four levels/four times in their envelope generator instead of an ADSR. See envelope generator.

Cancels the results of the last operation.

Unit number
The unit number is the device identification number designed for use with System Exclusive data operations. Most synths allow you to set this number in case you have two or more of the same ones so that you can send SyEx data to just one of them not all of them. It must match with the sending/recieving device when sending/recieving SyEx data. If you can't set the unit number, the synth usually uses the Gobal, Common or Recieve channel as the Unit number. Of course you should check your manual for certainty.

Voltage Controlled Amplifier. A circuit whose gain is determined by a control voltage.

Voltage Controlled Filter. A filter whose cutoff frequency or resonant frequency is determined by a control voltage.

Velocity Sensitivity
A keyboard which can respond to the speed at which a key is depressed; this corresponds to the dynamics with which the player plays the keyboard. Velocity is an important function as it helps translate the performer's expression to the music. Velocity may be routed to many destinations on your synth and is also translated over the MIDI line.

A cyclic change in pitch, usually in the range of 7 to 14 Hz.

Volatile Memory
Memory which loses its data when power is removed. The RAM memory in a sampler is volatile, the data on the hard disk is non-volatile.

Voltage Pedal
A pedal which outputs a control voltage which is dependant on its position.

Wave Generator used by Roland and others to describe their wave forms and parameters.

Write Protect
To protect data (either on a disk or in memory) from being written to, although data can still be read.

Zero Crossing
The point where the polarity of an electrical or sampled signal changes from positive to negative (or vice-versa) as it passes through zero. A zero crossing provides a convenient point to splice two sounds because the levels of the two splice points are the same at zero volts.

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