Dan Freeman – Director, BKDigiCon (The Brooklyn Digital Conservatory)
Many of these terms were sourced from the Juilliard School Center for Creative Technology 2022 Terms List.
| TERM | DEFINITION |
Amplitude Modulation | A synthesis technique to change the amplitude of a ‘carrier’ signal using the output of another ‘modulator’ signal. |
Low Frequency (or High-Frequency) Shelving | An equalizer that attenuates frequencies uniformly below or above the designated turnover frequency, respectively. |
Solo (Button) | (noun) In a recording console, a switch that disconnects the output of the normal monitor system from the monitor amp input. Instead, it routes the signal passing through the circuit or module containing that solo button directly to the monitor amp. The result is that only the signal from that source or module will be heard. (verb) To press a solo button on a recording console in order to hear only the signal passing through one module or channel. |
| Acoustic Delay | Delay derived from the time it takes sound to travel from the source to the listener, for instance from a speaker to the ear, or an instrument to a microphone |
| Additive Synthesis | A synthesis technique to use multiple sine wave oscillators and add them together in order to create complex tones. |
| Adjustable Oscillator | A device that generates a periodic waveform, which can be adjusted by multiplying with amplitude values. |
| ADSR | Attack, Decay, Sustain, Release. The four sections of every sound’s envelope. (see envelope) |
| Analog Recording | Any method of recording in which the recorded waveform is a continuous representation of the original signal. Example: conventional magnetic recording, direct to disc. |
| Analog-To-Digital Converter (ADC) | In digital recording, the group of circuits that sample the analog waveform, measure its instantaneous voltage, and convert this decimal value to its binary equivalent, in preparation for storage on tape (or on floppy disk, in random access memory, etc.). |
| Attenuation | A fixed or variable reduction in signal strength, which may in turn reduce the volume of sound heard. |
| Attenuation Pad (or Pad) | A resistive network or other circuit generally passive, that is inserted in an audio line to reduce the signal level. |
| Bandpass Filter | An equalizer that attenuates frequencies above and below a designated band. A low-pass filter thus allows low frequencies but not high frequencies to pass through. |
| Bandwidth | 1. Strictly speaking, the arithmetic difference between the highest and lowest frequencies that are (a) passed by an electronic device, or (b) present in a specific acoustic sound or audio signal. Example: The bandwidth of a telephone is approximately 2.2 kHz-i.e., 2,400 Hz minus 200 Hz. The endpoints of a circuit’s or system’s bandwidth are those frequencies at which its response or Output is attenuated by 3 dB. 2. The low and high frequencies of any specific frequency band. One might say, “The bandwidth of an electric guitar is 80 Hz to 8 kHz.” |
| Bit | The smallest unit of information that can be stored, transmitted, or processed by any digital circuit – e.g., a computer. Each bit is a “1” or “0” and corresponds to a single yes/no, on/off, or other similar decision. Abbreviated from BInary digiT. |
| Bitcrushing | The reduction of the accuracy of a digital signal that cuts away sonic information and eventually results in square waves. |
| BPM | Beats per minute |
| Cardioid Microphone | A uni-directional pattern, with the axis of minimum sensitivity at l80°. The pattern derives its name from its heart-shaped appearance. |
| Comb Filter | A filter that, through phasing cancellation, notches out a series of different frequencies in an incoming signal. This is the principle by which flanging is achieved. |
| Compression | 1. The squeezing together of air molecules during the first half of each complete cycle of a sound wave. It corresponds to the portion of the wave that appears above the axis when graphed. Opposite of rarefaction. 2. The audible result produced by a compressor. |
| Compression Ratio | The numerical ratio of the decibel increase in input level of a compressor (above the threshold) that produces a one decibel increase in output level. Example: If the increase in input level is 5 dB for every 1 dB increase in output, the compression ratio is 5:1. |
| Compressor | A signal-processing device consisting of an amplifier whose gain decreases automatically as the input signal level increases above a specified threshold. Some models use their own output signal to control gain reduction. The result is a decrease in the dynamic range of the signal from input to output, primarily by reduction of the level of transients or peaks in the signal. This can prevent overload on steep transients and, when the gain prior to compression is greater than unity, provide a boost for very low level signals. |
| Condenser (or Capacitor) Microphone | A microphone in which the vibrating diaphragm is electrically charged and acts as one plate of a capacitor. The movement of the diaphragm or membrane with respect to a rigid plate (charged with the opposite polarity) causes a tiny change in the potential between them. This is amplified by an internal pre-amplifier and sent to the recording console. DC power is required to run the pre-amplifier. Works like an electrostatic speaker in reverse. |
| Controller | A buzzword for an input device (see input device). Often when something is referred to as a controller in interactive theater it is being used in a custom or non-standard way (ie: a Wii remote being used to manipulate video effect parameters). |
| Convolution | A type of cross-synthesis. A convolution multiplies every frequency content in one sound by every frequency content in another (sometimes called a cross-multiply). |
| Cross Synthesis | A technique of impressing the spectral envelope of one sound on the flattened spectrum of another. |
| Cue Mix | The blend of live inputs and/or previously recorded tracks sent by the engineer to the headphones of performers playing or singing in the studio. Also called the headphone mix. |
| Cut-Off Filter | An equalizer that sharply attenuates all frequencies that are above or below a designated limit. |
| DAW | Digital Audio Workstation. A software program containing a Sampler, Audio Effects Processiing, MIDI Sequencing and Virtual Instruments. Examples include Logic, Ableton Live, FL Studio, ProTools, Cubase. |
| Decay | 1. Used both for acoustical and electronic sound sources. The characteristic fall-off in output amplitude or volume of a sound producing source emits when the force creating the vibrations (or the current powering the oscillator in a synthesizer, for instance) is removed. This term is often confused with release, the fourth section of a sound’s envelope. 2. The second of four sections of a sound or signal’s envelope. In order, they are attack, decay, sustain, release. |
| Decay Time | The length of time it takes for echoes or reverberation of a sound to diminish 60 dB below its original level, effectively to inaudibility. More precisely known as reverberation time. |
| Decibel (dB) | Loosely, the smallest increment in perceived volume that the average human ear can detect. In early experiments with sound, it was noted that 1/10 Bel is very close to this increment; thus, precise measurements of volume are standardized in decibels. |
| Delay | The time interval between the initial occurrence of a sound or signal and its repeat or echo. |
| Diaphragm | The part of a microphone (the membrane) or loudspeaker (the cone) that moves in response to sound waves or an incoming signal, respectively. |
| Digital Delay (DDL) | An electronic delay line in which the time delay is created by translating the analog input signal into digital information, which is stored for a determined or adjustable length of time, then reconverted back to an analog signal and sent to the output. Many DDLs allow adjustable regeneration or feedback, causing multiple repeats, and other effects such as flanging or chorusing of the input signal. |
| Digital Recording | The original analog waveform is sampled, yielding a voltage value for each sample. These values are converted to binary numbers which are encoded on tape as a biphase signal. Upon playback, the voltage values are reconstructed, then filtered and smoothed. (Sampling at a rate less than the nyquist frequency results in an incorrect replica of the original waveform. Sampling at or above the nyquist frequency results in a duplicate of the original waveform.) |
| Digital-To-Analog Converter (DAC) | A group of electronic circuits that reads and decodes sequential numerical voltage samples, then recreates a stepped waveform that approximates the analog waveform existing before initial encoding. The voltage samples may come from any storage medium, tape, RAM, a buffer memory, etc. |
| Distortion | Any change in the waveshape of a signal that occurs between the input and the output of an audio device. Strictly speaking, equalization and compression are types of distortion, even though they are used to “enhance” sound or make it more usable. |
| Doubling | 1. The recording on a multitrack system of a second performance of an instrumental or vocal part already recorded once (played or sung by the same performers), usually done to achieve a fuller sound. 2. Loosely, creating the aural impression of more players and/or singers than were originally recorded by mixing a slightly delayed duplicate of their track(s) in with the direct signal. |
| Dynamic control | Having the ability to manipulate a parameter in real time. A light switch dimmer gives a person dynamic control over the light. |
| Dynamic Filter | An equalizer whose operating bandwidth changes automatically in response to changes in program level, frequency content, or some other parameter. |
| Dynamic Loudspeaker | A loudspeaker in which the diaphragm or cone is attached to a coil of wire that moves through a magnetic field in response to the electromagnetic field created when an audio program signal flows through the coil. Also called moving coil loudspeakers. |
| Dynamic Microphone | A moving coil or ribbon microphone, in which the movement of the diaphragm (with its attached coil of very fine wire) or ribbon through the field of a permanent magnet induces a varying output voltage. This voltage is sent to the recording console. Works like a dynamic loudspeaker in reverse. |
| Dynamic Range | The number of decibels between the levels of the loudest and softest sounds that can be made by an instrument, between the loudest and softest passages in a live or recorded piece, or between the loudest and softest sounds that can be accurately reproduced, processed, or captured by a piece of audio equipment. |
| Dynamic Signal Processor | Any electronic device whose type or degree of operation changes in response to level or other characteristic of the input signal-e.g., compressors & noise reduction systems. |
| Envelope | If the amplitude vs. time graph of a musical sound is plotted, the envelope of the sound is the overall shape of this graph. More exactly, the curve and its reflection that enclose the waveforms comprising a sound. A sound’s envelope includes its attack, decay, sustain, and release. (see ADSR) |
| Equalization (“EQ” ) | The process by which one electronically modifies the frequency response of an audio system, and thereby the relative frequency content or energy distribution curve of an audio signal passing through it. |
| Equalizer (EQ) | Any signal processing device used to change the frequency response, relative frequency content, or spectrum of signals passing through it. Equalizers are sometimes mistakenly called filters. Filters may be used in equalizer circuits, but only the passive equalizer can properly be called a filter, since it can only detract from the input signal. |
| Fader | An adjustable level or “volume” control, usually linear in design and operation. |
| Fast Fourier Transform (FFT) | a mathematical method for transforming a function of time into a function of frequency. Sometimes it is described as transforming from the time domain to the frequency domain. It is very useful for analysis of time-dependent phenomena. |
| Filter | An equalizer that attenuates designated frequencies or bands. These bands may be very narrow or quite wide. |
| Flanging | The characteristic sound created by mixing a direct signal with the same signal, slightly delayed by a continuously varying amount of time. As the delay time varies, certain frequencies in the signal are reinforced or completely phased out. These frequencies travel up or down throughout the entire spectrum as the delay time varies, “combing” the spectrum. Originally discovered when playing two copies of the same tape synchronized on separate decks, then manually applying drag to the flanges of one tape reel or the other so that a small delay is introduced between the two identical programs. |
| FM Synthesis | FM synthesis can create both harmonic and inharmonic sounds. For synthesizing harmonic sounds, the modulating signal must have a harmonic relationship to the original carrier signal. As the amount of frequency modulation increases, the sound grows progressively more complex. |
| Frequency | Concerning any acoustic sound wave or cyclically varying electric signal, the number of complete vibrations or cycles per unit. Frequency correlates to both wavelength and pitch; the higher the frequency the higher the pitch and shorter the wavelength. |
| Frequency Response | 1. A graph of the amplitude vs. frequency, either for an acoustic sound or for a signal passing through any piece of audio equipment. 2. The graph that shows an audio device’s output amplitude through a wide frequency band, when the amplitude of the input through that band is constant. So-called “flat” response indicates a horizontal, straight line response “curve” (as it is often called), which in turn means that the device passes all frequencies equally well, or without coloration. |
| Fundamental | The frequency of the first in a series of partials which make up the timbre of a musical sound. This first partial w ill also have the highest amplitude in the series and will be the frequency we recognize as the pitch of the musical sound. eg.: The fundamental of a complex musical waveshape at A440 will be 440Hz. |
| Gain | The ratio of the signal level at the output of an audio device to the signal level at its input. Normally expressed in decibels. Unity gain, for instance, denotes identical input and output levels. A gain of 6 dB indicates that a device amplifies signals by 6 dB, equivalent to a doubling of the signals’ voltage. |
| Granular Synthesis | A method by which sounds are broken into tiny grains which are then redistributed and reorganized to form other sounds. |
| Graphic Equalizer | An equalizer whose controls are a set of sliding pots, usually arranged in a row, and each of which adjusts the amount of boost or cut in a specified band of the input signal’s overall frequency content. The positions of all the controls gives a “graphic” representation of the frequency response curve that is applied to any input signal. |
| Hardware | The physical elements and materials that make up a computer or device. A computer, keyboard, and mouse are all pieces of hardware. |
| Harmonic | An integer multiple of the fundamental frequency of a sound. The first harmonic (also called a “partial”) is the fundamental itself the second harmonic is two times the fundamental, etc |
| Hertz | Abbreviated Hz. Formerly called cycles per second. The unit by which frequency is measured and specified. |
| Input | The connection by which a signal enters an electronic device. |
| Input | Information/commands/audio/video that is taken in by a computer or device. If you flip a light switch, that is an input command. |
| Input Device | Any device used to send control information to software/hardware. The light switch is the input device to the bedroom light circuit; the remote control is the input device for the TV; the keyboard and mouse are the input device for the computer. |
| Interactivity | The ability to have one thing affect another, as in movement affects lighting; or sound affects video. Perhaps you connect a “clap on” unit to your light switch. Clapping your hands (making sound) would control lighting (would make it turn on or off). |
| LED | Light Emitting Diode. An electronic component that allows current to flow in only one direction through itself, and emits light whenever current is flowing. |
| LED Display | One or more LEDs used to indicate the operational status of a piece of electronic equipment, or the varying level of a signal being processed, or simply peak or VU levels. The series of LEDs must be driven by a circuit that senses these levels or conditions, turning on only the appropriate LEDs at each moment. |
| Level | Generally, the SPL or “volume” of sound in the listening environment; or the amplitude of the audio signal present on tape, passing through a console or other device, etc. Expressed in decibels according to the various scales that apply to electronic signals or acoustic sound pressure. A potentially misleading term unless the context of its usage is well defined. |
| LFO (Low-Frequency Oscillator) | A circuit whose output is generally used to control some parameter of another signal-generating or signal-processing device. LFO output, when applied to audio signal level, produces a tremolo. When used to modulate delay time, an LFO produces flanging, etc. |
| Limiter | Technically, a compressor whose ratio is infinite-i.e., its output level will never exceed a specified value no matter how much the input level increases over the threshold. Practically, any compressor whose ratio is greater than 10:1. |
| Loudspeaker | Any transducer that converts the electrical energy of an audio signal into acoustical energy or sound. |
| Magnetic Recording Tape | A medium capable of recording the changes in an electrical signal in the form of varying intensities of magnetism encoded along its length. Magnetic particles, such as iron oxide, are suspended in a paint-like binder and coated onto continuous plastic or other film base. When passed by an electromagnet through which an audio signal flows, the particles are magnetized in proportion to the instantaneous level of the signal. This linear magnetic “record” can then be reproduced as it in turn passes over a sensitive electromagnetic generator creates an electrical signal in proportion to the magnetism present along the length of tape. |
| Master Fader | A single fader that controls the level of all the tracks being recorded or mixed. |
| Microphone | Any transducer that converts acoustical energy or sound into an electrical audio signal. |
| Microphone (or Mic) Level | An electronic signal level (actually a range of levels) that corresponds to the output level of the “average” microphone. |
| MIDI | Musical Instrument Digital Interface. A digital data format or scheme in which control signals generated by the keyboard commands played on one synthesizer can trigger the tone-generating circuits of other synthesizers. One player can thus simultaneously draw on the unique sound settings or patches of several synthesizers to create combined effects that would otherwise be impossible. |
| Mixing Board (Console or Desk) | The set of controls (and the enclosure containing them) by which the recording engineer selects various input signals (mic, line, or tape playback), adjusts their relative volume, tone, etc., and routes them, either to multi-track tape, mixdown, control room monitors, studio headphones, or other destination. |
| Monitor | (noun) A loudspeaker in a control room or other listening area. (verb) To listen back to a recorded performance or a live performance in the control room. |
| Monophonic (Mono | Literally, single sound. In monophonic recording or playback, all sounds are blended together on one channel or track, or heard from a single loudspeaker. |
| Mute | To turn off a sound, input, or track. |
| Network | A collection of interacting and communicating computers, input devices, and/or output devices. |
| Noise Gate | An expander whose threshold can be set to totally eliminate or attenuate low-level signals, such as noise. Current models allow the user to select the threshold level (i.e., the lowest signal level that will “open” the gate or pass through it unaltered), the rates at which the gate “opens” and “closes” to allow program signal through (called attack and release times), the amount of attenuation in effect when the gate is “closed” (called the floor), and other variables. |
| Normalled Connection | In a recording console or other electronic device, a pre-designated and continuous signal routing connection that can be interrupted by insertion of a patch cord at the corresponding point in the patch bay. The normalled connection is then “broken,” allowing the engineer to re-route as he desires. |
| Notch Filter | A filter that severely attenuates a very narrow band of frequencies. Often used to eliminate steep resonances in an instrument’s response, or to get rid of motor hums, feedback, room resonances, and other unwanted sounds that may have been present when a signal was recorded. |
| Omni-Directional Microphone | A nearly circular pattern, indicating equal sensitivity to sounds approaching from all directions around the microphone. |
| Oscillator | The basic sound-generating circuit in most traditional synthesizers. A control voltage generated by each key of the keyboard (or other controller) instructs the oscillator what output frequency is required. This can then be processed by any number of other circuits. |
| Output | Information/commands/audio/video that is sent out by a computer or device. If once you flipped a light switch, the light comes on… the light coming on is the output. |
| Overtone | An integer multiple of fundamental frequency. The first overtone is twice the fundamental, the second is three times the fundamental, etc. |
| Pan Pot | A multiple pole potentiometer used to vary the proportion of an incoming signal sent to two or more separate outputs. Generally used to position sounds left to right in a stereo mixdown, or to distribute one signal to two tracks in a multi-track recording. |
| Parameter | A controllable variable. A bedroom light has a power parameter which can be “on” or “off.” In interaction we seek to quantify parameters, so if I send the light switch the value of “1” it would be on, and “0” it would be off. Perhaps the light is on a dimmer. I could send the switch “0.4” and it would be at 40% brightness. |
| Parametric Equalizer | An equalizer in which the center of the frequency band that each boost/cut control effects can be continuously varied over a wide range. The amount of boost or cut for each band is separately adjustable. Sometimes the bandwidth that each boost/cut control effects can also be varied by a second control. The bandwidth parameter is often erroneously called Q. |
| Patch | (noun) – A particular sound produced by a synthesizer, either preset at the factory, or programmed by the performer. Example: A clarinet or harpsichord patch-i.e., the synthesized sound of that instrument. (verb) – To route a signal in via a desired path, usually by use of the patch bay and patch cords. |
| Patch Bay | In a recording console or equipment rack, one or more rows of female input and output jacks, used in conjunction with patch cords to route signals through outboard signal processing gear, or to reroute signals inside the console itself. |
| Patch Cord | A short length of audio cable with an audio plug on each end, used for signal routing in a patch bay. |
| Peak Level | The instantaneous highest level of the transient in any signal or series of signals. Because these transients are so short, meters designed to read peak levels have circuitry built in that remembers and holds the level on display long enough for the meter itself to reach the peak’s full level and be observed by the engineer |
| Phase | The time relationship of two or more sound waves reaching the same point in space simultaneously, or of two or more signals passing through the same point in an electronic circuit simultaneously. If the two sounds or signals are of identical frequencies, they are “inphase” if the peaks and troughs of the waves occur simultaneously. They are “out? of phase” if the peaks of one partially or fully cancel the peaks of the other. The degree of “out-of-phaseness” is designated in degrees (x°) such that 0° phase difference indicates two sounds or signals exactly “inphase,” and 180° phase difference indicates the two are completely “out-of-phase,” cancelling each other completely. |
| Phase Cancellation | The attenuation that results when two acoustic or electric waves of the same frequency but opposite or nearly opposite polarity combine. |
| Phase Vocoder, Pitch Shifting | an implementation of Fourier analysis in computer music, to manipulate the length of the sound without changing its pitch and, conversely, to change its pitch without affecting its length. This is called time stretching and pitch shifting. |
| Pitch Tracking (detection) | an algorithm designed to estimate the pitch or fundamental frequency of a quasiperiodic or virtually periodic signal, usually a digital recording of speech or a musical note or tone. This can be done in the time domain or the frequency domain or both the two domains. |
| Polar Pattern | The graph of the sensitivity of a transducer. |
| Pre-amplifier or Preamp | In a console or other audio system, the first stage of amplification, in which very low level input signals, such as from a phonograph cartridge or microphone, are boosted to line level (or some usable level). |
| Ring Modulation/Sidebands | A type of Amplitude Modulation — the two signals are simply multiplied. Ring Modulation will generate a frequency spectrum containing two sidebands, which are the sum and difference of the carrier and modulator frequencies. When this occurs, the actual carrier frequency is removed from the spectrum, leaving two harmonic sidebands. |
| Sample | 1. To take regular measure of an analog signal. 2. Any single measurement of such a voltage. 3. To digitally record one or more sounds intended as a sound source for playback via keystrokes on a synthesizer or other device. One might, for example, sample a frog croaking, and later reproduce the croak at any desired pitch through the various keys of a synthesizer. |
| Sampling Rate (or Sampling Frequency) | The number of samples a digital recorder takes per second for each signal channel or track. Expressed in hertz, although this term does not exactly apply, since sampling, though a repetitive process, has nothing to do with audio frequencies per se. Various professional digital recorders sample at 44,100, 48,000, or 96,000 Hz. CD players have a 44.1 kHz sampling rate. |
| Saturation | A subtle form of distortion that produces pleasant-sounding harmonics. Originally it resulted from tube amplifiers and is now modelled by many digital plug-ins |
| Sequencer | A physical or virtual machine that allows for the programming of sequences to send to an instrument for automatic playback. Ex: Piano Roll and Player Piano |
| Shelving Equalizer | An equalizer that raises or lowers frequencies beyond its turnover frequency by a fixed and continuous amount. A shelf boost of 6 dB above 5 kHz will thus increase all frequencies in the signal above 5 kHz by 6 dB. |
| Shock Mount | A microphone suspension system that prevents mechanical vibrations of the stand from reaching the mic. Usually made of elastic bands mounted on a metal frame, which together hold the mic in position without rigid mechanical contact with the stand. |
| Signal | The electric current that carries audio information. |
| Signal Processing Device | Any audio system used to alter the characteristics of a signal passing through it. Examples: equalizer, compressor, noise gate, etc. |
| Sine Wave | The waveform of pure tone or single frequency. One of the three basic waveforms produced by synthesizers, the others being square and sawtooth waves |
| Software | machine-readable information that provides instructions to a computer. Microsoft Word, OSX, and Gmail are all software. |
| Stereo (Stereophonic) | A type of audio system that uses two or more speakers or channels to reproduce spatial information, giving the listener the illusion of lateral placement of sounds between two speakers and their relative distance from the listener. |
| Storage Medium | Any type of material on which analog recordings or digital data is permanently saved i.e., recording tape, floppy disk, hard disk, optical disk or CD, punched paper tape, etc. Technically, even a common LP is a storage medium for analog information. |
| Synthesizer | An instrument that produces sound waves from a physical or virtual oscillator |
| Tape Delay | A delay produced by recording and playing back a sound or signal simultaneously on the same recorder, taking advantage of the time it takes the tape to travel from the record to the playback head. Also, the tape and recorder with which this is done. Tape delay was used long before digital and other systems were developed. Because the heads are stationary, the only way to adjust the delay time is by changing the tape speed itself. Sometimes called a slapback. |
| Threshold | For any dynamic signal processor, the input level at which the device starts functioning. |
| Transient | A sudden, high-amplitude signal peak that decays to the average program level very quickly. Percussive instruments create steep transients with every note. |
| Transistor Saturation | Emulates audio driven through transistor-based circuits that produce odd order harmonics and a form of “hard clipping” compression. |
| Tremolo | A wavering quality in a steady musical tone or sound, caused by a cyclical change in its volume level above and below its nominal level. Often confused with vibrato. |
| Tube Saturation | Emulates audio driven through tube amps which produces even order harmonics and subtle compression |
| Vibrato | A wavering quality in a steady musical tone or sound, caused by a cyclical change in its musical pitch (or fundamental frequency) above and below its nominal pitch. Often confused with tremolo. |
| Wavelength | The measurement of one complete cycle of a sound wave. That is, the physical length between two crests and two troughs of a wave. |
| Wavetable Oscillator | A synthesis technique based on periodic reproduction of single-cycle waveform. |
| Word Length | The number of bits composing each word of digital data. The more bits in each digital audio sample, for instance, the greater the number of quantizing increments by which the incoming analog wave can be represented. This, in turn, affords greater accuracy in recording and reproduction of the original waveform. |
| XLR Connector | A three-pin grounded and lockable audio connector designed for professional use, especially in balanced lines. |