Reference desk · A–Z

Glossary

The vocabulary of live sound spans acoustics, electronics, rigging, networking, and psychoacoustics. These definitions follow the archive’s historical context.

Microphone and acoustics terms are adapted, in our own words, from the DPA Microphones Mic Dictionary.

1

11.1.4: Format for immersive recording/reproduction, indicating 11 microphones/channels for the main layer, one channel for the low-frequency effect (LFE), and four upper layer channels for height information.
11.1.6: Format for immersive recording/reproduction, indicating 11 microphones/channels for the main layer, one channel for the low-frequency effect (LFE), and six upper layer channels for height information.
1st Order Pattern: Standard microphone patterns like cardioid, supercardioid or figure-of-eight are known as first-order patterns.

3

3:1 Rule: Phase peaks and dips from the same sound source occur when panned to the same position at the same level, which will be the case using more than one microphone.
3D Sound: See Surround Sound.
3DoF/6DoF: Three or six Degrees of Freedom.

4

4FSK: Four Level Frequency Shift Keying.

5

5.1 Surround Sound: An audio format involving five channels of full bandwidth audio: center, left, right, left surround and right surround.

6

6.1: An alternative variation on 5.

7

7.1: An alternative variation on 5.
7.1.4: Format for immersive recording/reproduction, indicating seven microphones/channels for the main layer (Left, Center, Right, Left & Right Surround, Left & Right Rear Surround), one channel for the low-frequency effect (LFE), and four upper layer chann

9

9.1.4: Format for immersive recording/reproduction, indicating nine microphones/channels for the main layer (Left, Center, Right, Left & Right Wide Surround, Left & Right Surround, and Left & Right Rear Surround), one channel for the low-frequency effect (L

A

A-B testing: A comparative process where two different audio signals or setups are evaluated to see which one performs better.
A-D: The conversion of continuous analog audio waves into a series of digital data points.
A-filter: See A-weighting.
A-Format: A four-channel raw output from a tetrahedral microphone array used in immersive audio recording.
A-weighted Sound Pressure Level: Sound pressure level measured with an A-weighting function involved.
A-Weighting: A frequency filter that adjusts sound measurements to mimic the sensitivity of human hearing at lower volume levels.
A1, A2: In production for theatre: A1 is the person that makes the audio mix.
AAC: Advanced Audio Coding.
ABC stereo: Term used for a three-microphone setup like the Decca tree (see this).
Absorption: The process by which a material captures sound energy and prevents it from reflecting back into a room.
Absorption Coefficient: (symbol: α) The practical unit between 0 (no absorption) and 1 (full absorption) expressing the absorbing properties of a material.
ABX: A method of comparing two versions – A and B.
AC-3: A multi-channel digital audio compression standard commonly used in cinema and DVD production.
Accelerometer: A transducer designed to pick up vibrations in solid constructions.
Acceptance Angle: The angle between points on a microphone’s polar response curve where the sound level drops by 3 dB compared to the on-axis level is called the acceptance angle of the microphone.
Accuracy: When measuring microphone data to be published, the standards specify an accuracy for the measurements to ensure trustworthy and comparable results.
Acousmatic (music): The term acousmatic was adopted by French composer and musician Pierre Schaeffer, derived from the Greek word akousma/akousmatikoi, meaning “hearing” or “thing heard.
Acousmatic (sound): The word acousmatic comes from the Greek word akousma/akousmatikoi, which referred to students of the philosopher Pythagoras who, according to the legend, had to listen to him give lectures from behind a veil or screen to help them focus better on hi
Acoustic Baffle: See Baffle .
Acoustic capacity: An expression that calculates the maximum number of people to have a conversation across tables (in a restaurant or similar place) without needing to raise their voices to be able to hear each other and perceive the speech: Room volume [m∧3] divided
Acoustic ecology: Ecology is the study of the relationship between living organisms and their environment.
Acoustic Equalizer: Acoustic equalizers or acoustic pressure equalizers (APEs) are sphere-shaped accessories designed for use with omnidirectional microphones.
Acoustic space: The profile of a sound over the landscape.
Acoustics: The branch of physics that studies sound waves and their behavior in physical spaces.
Acousto-mechanical pattern changing: A principle of controlling the directivity of a microphone by changing the admittance of sound to the back of a microphone diaphragm, for instance, switching from omnidirectional (only frontal sound, no sound entering the rear) to a cardioid (some so
Active Antenna: A wireless receiver antenna equipped with a built-in amplifier to compensate for cable signal loss.
Active Drive: Active drive is a technology implemented in microphone preamplifiers.
Actuator: Electrostatic actuators are used to simulate the pressure response of condenser microphones.
ADC: An electronic device that translates analog sound voltages into digital signals for processing.
ADPCM: Adaptive Differential Pulse Code Modulation (see this).
AES: Audio Engineering Society (see this).
AES/EBU: A standard professional interface for transmitting two channels of digital audio over a single balanced cable.
AES67: AES67 is a technical standard for audio over IP (AoIP) and audio over Ethernet (AoE) interoperability.
AFM: Audio FM (see this).
Aging: Aging is a process that microphones or microphone materials may undergo to stabilize or release mechanical tensions that else might influence the performance over time.
AIFF: A high-quality, uncompressed audio file format originally developed by Apple.
Alias (theatre console): A reusable, updatable set of processing settings, such as the EQ for a character's hat, that can be recalled in any cue; refinements made in one cue carry over to every other use.
Ambience: Spatial effect, notably mixing of remotely placed microphones in order to include the atmosphere of the room on the recording.
Ambient Noise: The noise level associated with a location in the absence of foreign excitation.
Ambisonics: A surround sound technique that captures audio from all directions to create a full sphere of sound.
Ampere: A unit for electrical current.
Amplitude: The physical magnitude of a sound wave, which determines its perceived loudness.
Amplitude Modulation (AM): Transfer of information by the variation of the amplitude of a carrier wave.
Analog: An audio signal represented by a continuous electrical voltage that varies in sync with sound pressure.
Analog to Digital Converter (ADC): A circuit that converts an analog signal to a digital signal.
Analysis Of Variance, ANOVA: A test for data, such as listening test results, assesses whether the means of two or more groups are equal by comparing the variance between group means to the variance within groups.
Anchor Element: The perceptual loudness reference point or element around which other elements are balanced in producing the final mix of the content.
Anechoic Chamber: A specialized room designed to absorb all sound reflections, creating a completely echo-free environment.
Antenna Diversity: A system using multiple antennas to improve the reliability of wireless audio signals and prevent dropouts.
Antenna Length: In wireless audio: The physical length of an antenna is strongly related to the wavelength of the radio wave.
Anthrophony: A term used in the soundscape definition of sound sources.
Anti-aliasing: In digital audio: Low-pass filter for the removal of frequencies that otherwise would create "alias" frequencies that were not present in the signal originally.
AoIP: Audio over Internet Protocol - term for Audio in IP-based networks.
APT-X: Proprietary audio codec, provides bitcompression scheme often applied to Digital Cinema, Blutooth and other wireless applications, like wireless microphones.
Array Microphones: Multiple microphones (from two to hundreds) arranged to obtain directionality, either by direct summing of all microphone's signals or by adding signal processing to the summation process.
Artificial mouth: An acoustic device, containing a small loudspeaker and a cavity to simulate the oral organ.
ASIO: A driver protocol that enables audio software to communicate directly with hardware for minimal latency.
ASK: Amplitude Shift Keying.
Asynchronous Sample Rate Converter: When two (digital) devices cannot be synchronized (for example, a CD player with a mixer) even a small deviation between the clock frequencies of the two devices will cause occasional glitches due to the accumulation of shortages or excesses.
ATR: Audio Tape Recorder.
ATRAC: Adaptive Transform Acoustic Coding.
ATSC: Advanced Television Systems Committee.
Attack: The initial portion of a sound wave or the time a processor takes to react to a signal.
Attenuate: To reduce the strength or volume level of an electronic audio signal.
Attenuator: A device used to control the level of an electrical signal.
Audibility Threshold: The sound pressure level, for a specified frequency, at which people with normal hearing begin to respond.
Audio: That part of sound technology that concerns itself with the recording and reproduction of sound.
Audio Bridge: Dialogue or sound effects in one scene that continues over into a new shot.
Audio Engineering Society: A society for audio professionals.
Audio FM (AFM): Designation for a video recorder's frequency-modulated sound track.
Audio Frequency: The range of sound vibrations detectable by the human ear, typically from 20 Hz to 20 kHz.
Audio Interchange File Format (AIFF): An uncompressed audio format developed by Apple.
Audio object: A signal accompanied by metadata describing how it should be positioned or rendered, rather than assigned only to a fixed output channel.
Audio Stream Input/Output (ASIO): ASIO is a PC sound card driver protocol for digital audio.
Auditory Fatigue: A reduction in the sensitivity of the human auditory system caused by prolonged exposure to sound.
Augmented Reality (AR): An additional layer on top of reality; the physical world mixed with virtual elements.
Aural space: The space on any graph that results from a plotting of the various dimensions of sound against one another.
Autolocate: Facility on a tape unit's transport system.
Automatic Dialog Replacement (ADR): Automatic replacement of location dialog with studio dialog.
Automatic Gain Control (AGC): Method by which the amplification in a circuit is controlled by the input voltage or another parameter.
AUX: An auxiliary signal path on a mixer used to send audio to external effects or monitor mixes.
AVB: Audio Video Bridging.
Azimuth: The horizontal angle of a sound source relative to a listener or the alignment of a magnetic tape head.

B

B-format (microphones): A recording format virtually based on three orthogonally-oriented figure 8 microphones (X, Y, Z) and one omnidirectional microphone (W).
Back Lobe (Back Lobe Shape): An expression related to the directivity pattern of antennas and microphones.
Background Sounds: Sounds at a level that is low, relative to the foreground sounds, which are incidental, or which are not required for understanding or appreciation of the program.
Backline: In sound reinforcement, usually an expression for the audio equipment (behind the artists) on a concert stage.
Baffle: 1. A movable barrier used in the recording studio to achieve separation of signals from different sources (sometimes called “gobo”).
Balance: A spatial descriptor in audio assessment.
Balanced and Unbalanced Lines: Balanced line is a transmission line consisting of two conductors of the same type and equal impedance to ground and other circuits.
Balanced line: A two-conductor signal connection that rejects noise common to both conductors at the receiving input.
Band-pass Filter: See Filter, Band-pass.
Bandwidth (-3 dB): The spacing between the frequencies at which a response attenuates by 3 dB.
BAS: Abbreviation for Broadcast Auxiliary Service.
Bass Depth: A timbre descriptor (bass range) in audio assessment.
Bass Management: A circuit that utilizes the subwoofer in a 5.
Bass Precision: A dynamics descriptor, a parameter for listening tests.
Bass Strength: A timbre descriptor (bass range) in audio assessment.
Batch: The number of sound or video media produced in the same fabrication process.
BCD: Binary Coded Decimal.
Beam steering: Electronic control of an array’s radiation direction through calculated phase, delay, and amplitude differences among elements.
Beamforming: Generating specific directional characteristics based on the combination of signals for microphones in a microphone array (see this).
Bed: An expression used with immersive audio formats like Dolby Atmos: A multichannel mix bus or audio stream with a fixed channel configuration (unlike objects, which are not created from a fixed number of channels).
Bel, B: Relative logarithmic unit for the measurement of sound levels.
Belt Pack: A compact wireless transmitter for lavalier microphones.
BFL: Abbreviation for Broadcast Fiber Link.
Bias: 1: In magnetic recording: A high-frequency, alternating current (typically 100 kHz) that is added to the recording head in a tape recorder together with the sound signal.
Bidirectional Microphone: A microphone with a polar pattern like the figure-of-eight.
Bimorph Element: Piezoelectric microphones are built on the principle of voltage generated by the flexing of piezo crystals.
Binary: Number system that only contains two digits.
Binaural Recording: Stereo recording using either an artificial head with built-in microphones or a real person with small microphones in – or close to – the ear canals.
Biophony: A term used in the soundscape definition of sound sources.
Biphase Modulation: A form of modulation that, among other things, is used by the AES/ EBU interface and time code.
Bit: Smallest unit in digital technology, with a value of either 0 or 1.
Bit Companding: A technique for digital audio via which greater contrast can be obtained for a given number of bits.
Bit rate: A measurement of how many bits of data are recorded or streamed per second.
Bit Reduction: As linear quantization can result in a larger number of bits per second than there is room for in a transmission channel or on a storage medium, the number of bits is reduced, preferably in a manner so that it cannot be heard in the audio signal.
Bit resolution: The number of bits per sample, sometimes called word length.
Bit Stream Converter: See Delta-Sigma Converter.
Blast Shield: Protective tool to place in front of a microphone to avoid excessive air blows to reach the microphone diaphragm.
Blimp: Due to its shape, a windshield for long microphones like shotguns is often called blimp or zeppelin.
BLM: See Boundary Layer Microphone.
Blu-Ray: An optical disc with the exact dimensions of a CD and DVD.
Bluetooth: A wireless data network (WPAN, Wireless Personal Area Network).
Blumlein: Microphone configuration named after the inventor Alan Dower Blumlein (1903-1942).
BNC: The BNC connector is a bayonet-locking type for two-conductor coaxial cable, introduced in the late 1940'es.
Body Pack: See Belt Pack.
Boom: A long handheld pole for microphones, often used in film production.
Boomy: A timbre descriptor (bass range) in audio assessment.
Bounce: Transfer of several audio tracks to a new one (typically mono or stereo).
Boundary Layer Microphones: Microphones placed directly on the surface of a large boundary (like a table- or wall surface).
Boxy: A timbre descriptor (bass range) in audio assessment.
Breathy Voice: The result of a widened glottis with excessive airflow that produces air turbulence.
Brilliance: A timbre descriptor (treble range) in audio equipment assessment: Treble or high frequency extension.
Broadband: See Wideband.
BS.1770: Formally ITU-R BS.
Bubbling: A signal-related descriptor in audio assessment: Sound or noise with fast (<1 sec.
Bus: A common set of conductors where many signals are gathered, for example in a mixer console.
Buzz Track: In film: A soundtrack of natural, atmospheric, on-location background noise that is added to the recorded track of actors' dialogue and other sound effects recordings to create a more realistic sound.
Buzzing: A signal-related descriptor in audio assessment: A zzz-like, undesirable sound typically in the low and midrange frequencies.
Byte: Data word, consisting of a number of bits, normally 8.

C

c/n: In wireless transmission: Carrier to Noise Ratio.
Calibration: The process of measuring to determine the accuracy of the measurement chain.
Calibrator, Acoustic: A device that produces a known sound pressure on a microphone in a sound level measurement system.
Camcorder: A contraction of the words camera and recorder; the recording medium and the camera are built together as a unit.
Canny: A timbre descriptor (bass range) in audio assessment.
Capacitance: Capacitance is the ability of a component or circuit to collect and store energy in the form of an electrical charge.
Capacitor: A capacitor is an energy-storing device.
Capacitor Microphone: See Condenser Microphone.
Carbon Microphone: A microphone element that consists of two metal plates separated by granules of carbon.
Cardioid Microphone: A microphone with a unidirectional characteristic that picks up sound in the front.
Carrier: A waveform (typically a sine wave) whose frequency or amplitude is modulated by a signal.
Cartridge: Special tape cassette with 1/4-inch tape earlier used for jingles, ads, etc.
Cat #: Category of cables for Ethernet.
Cavity coupler: To determine the pressure sensitivity of a microphone, a rigid cavity is used to couple the sound source to the microphone.
CCIR: Comité Consultatif International pour la Radio (Consultative Committee on International Radio).
CD quality: A term used to describe 16-bit digital audio recorded at 44.
CELP: Abbreviation for Code-Excited Linear Prediction.
Center Frequency: The arithmetic center of a constant bandwidth filter or the geometric center (midpoint on a logarithmic scale) of a constant percentage bandwidth filter.
Ceramic microphone: See crystal microphone.
Channel Layout: Channel layout is how the tracks/stems/groups/objects are organized in the mixing console, the DAW, or the media used for storage or reproduction.
Channel Packing: In wireless transmission: Methods to maximize the number of channels available within a given bandwidth of the radio wave spectrum, for instance, within the bandwidth of one designated tv-channel.
Channel Separation: The attenuation of one channel appearing in neighboring channels.
Channel Spacing: In wireless transmission: The distance in frequency between each channel in a group of channels in a frequency band.
Channel Width: In wireless transmission: The RF-frequency span for a modulated channel.
Charge (Microphones): An electric potential between back electrode and diaphragm that makes condenser microphones work.
Chest Voice: A term used within vocal music, especially in classical singing.
Clapboard: A small board that displays information for each shot in a movie or documentary and is filmed at the beginning of a take.
Clarity: A transparency descriptor in audio assessment.
Clean: A transparency descriptor in audio assessment.
Clean Sound: Atmospheric sound.
Clipped: A signal-related descriptor in audio assessment.
Clipping: Audio distortion that occurs when a signal level exceeds the maximum capacity of an amplifier or digital system.
Close-miking: Placement of a microphone near a sound source, thus effectively eliminating all but the direct sound from the source.
Close-talking microphone: Microphone for use at a distance of approximately 25 mm from the source of sound.
Close-talking sensitivity: The sensitivity of a microphone when measured in a short distance from the sound source, which in this case is an artificial mouth.
Cocktail party effect: The cocktail party effect refers to people's ability to focus on a single talking person or conversation in noisy environments.
Code-Excited Linear Prediction, CELP: This is a linear predictive speech coding algorithm, developed in 1985.
Coherence: A statistical indicator of confidence in a transfer-function measurement at each frequency.
Coincidence Stereo: Stereo techniques that use microphone capsules placed close together, in principle at the same point, i.
Coincident Microphone: Microphones are said to be coincident when two (or more) capsules are configured or mounted to receive the sound simultaneously.
Coloration: Non-uniformity in off-axis frequency responses resulting in a distortion of the tonal quality of the source.
Comb Filter: A distortion produced by combining an electrical or acoustical signal with a delayed replica of itself.
Common Mode Rejection Ratio (CMRR): When using balanced lines, the induced electromagnetic noise is rejected due to the common mode, the fact that the impedance is exactly the same between each leader and ground (pin 2 to 1 and 3 to 1 in a 3-pin XLR connector).
Compact Cassette, CC: Registered name for the cassette developed by Philips with a 3.
Compander: A contraction of compressor and expander.
Complex tone: A tone that consists of more than a single frequency.
Component Frequency: Another term for harmonic or partial.
Compressed: A signal-related descriptor in audio assessment.
Compression: Reduction of the dynamic range of recorded audio.
Compression driver: A high-efficiency driver whose diaphragm feeds a smaller exit through a phase plug before entering a horn.
Compressor: A device or a plug-in that provides reduction of the dynamic range of recorded audio.
Condenser Microphone: A type of microphone that uses a capacitor to convert sound vibrations into electrical signals.
Conductance (G): The ability of a material to conduct electricity.
Consonant: 1. In phonetics, a speech sound that is articulated with a complete or partial closure of the vocal tract (contrary to vowels).
Constant-voltage line: A transformer-coupled distribution method—commonly 70 V or 100 V—that carries audio to many distant loudspeakers.
Contact Microphone: A transducer that is mounted directly on the body of the musical instrument and picks up the mechanical vibrations of that instrument instead of the acoustical sound.
Convolution Reverb: Convolution reverb is a software-based process used for digitally simulating the reverberation of a physical or virtual space.
Core Audio: Core Audio is a driver protocol for digital audio in Apple's Mac OS X and IOS operating systems.
Corner Frequency: Transition frequency of a filter.
Coulomb: The unit of a coulomb is electric charge, and it is the standard unit for this quantity in the International System of Units (SI).
Creaky Voice: A perceptual result of subharmonic or chaotic patterns in the glottal waveform; if a subharmonic is below about 70 Hz, creaky voice may be perceived as pulse register.
Crest Factor: The term used to represent the ratio of the peak (crest) value to the RMS value of a waveform.
Critical Band: In human hearing, only those frequency components within a narrow band, called the critical band, will mask a given tone.
Critical Distance: The distance from a sound source in a room at which the direct sound and the diffuse, reflected sound has the same level.
Cross Fade: The process of gradually fading from one audio source to another.
Crossover: A filter network that divides the audio spectrum into bands for different loudspeaker sections.
Crossover Frequency: In a loudspeaker with multiple radiators, the crossover frequency is the -3 dB point of the network dividing the signal energy.
Crosstalk: Unwanted signal leakage between adjacent channels in a piece of audio equipment.
Crystal Microphone: Crystals which exhibit the piezoelectric effect (see this) create voltages when they are deformed.
Cue: Audio or visual information that concerns timing or synchronization.
Cue Wheel: Control button for use with slow forwards and backwards winding with cueing.
Cupping: Holding one or two hands around the grid of a vocal microphone.
Curbing: Term used in CVT (Complete Vocal Technique): Curbing is the half-metallic mode, meaning there is some metal in the notes.
Cutoff: The cutoff frequency of a filter.
Cycles per Second (CPS or C/S): Formerly used for the quantification of frequency, Hz.

D

D-A: Digital-Analog (digital to analog).
D-sub: A plug type that can be used, among other things, for the transfer of digital signals.
DAC: See Digital-to-Analog Converter.
Damped waves: A wave in which the amplitude decreases over time (contrary to continuous wave).
Damping: The reduction of vibrations or resonance in a physical system or acoustic space.
Damping material: A material that absorbs, reduces or disperses sound waves to control reverberation.
Dante®: Digital Audio Network Through Ethernet / AoE / AoIP.
Dark - Bright: A timbral balance descriptor in audio assessment.
DAT: Digital Audio Tape (-recorder).
DAW: Digital Audio Workstation, see this.
dB(A) or dBA: An acoustic measurement where an A-weighting band-pass filter is inserted in the measurement chain.
dB(C) or dBC: An acoustic measurement where a C-weighting band-pass filter is inserted in the measurement chain.
dBFS: Decibels, relative to full-scale sine wave (per AES17).
dBm: Logarithmic relation with a reference of 1 mW/600 Ω.
dBr: An abbreviation for decibels, relative.
dBTP: Decibels, true-peak relative to full scale (per ITU-R BS.
dBu: Logarithmic ratio with a reference of 0.
dBV: Logarithmic ratio with a reference of 1 V.
DC Coupling: The connection of a signal from one circuit to another in a manner that allows both AC and DC components to pass.
DC Offset: The change in input voltage required to produce zero output voltage when no signal is applied to a device.
De-clipping: An algorithm designed to reconstruct audio signals which exhibit clipped waveforms.
De-esser: Signal processing to reduce excess sibilance, typically in vocal recordings.
Decade: Ten times any quantity or frequency range.
Decay Rate: A measure of the decay of acoustical signals, expressed as a slope in dB/second.
Decca tree: A stereo microphone technique developed by Roy Wallace and Arthur Haddy at Decca Studios in London in the 1950s, most used for orchestral recordings.
Decibel (dB): A logarithmic unit used to measure the relative intensity or power of an audio signal.
Decibel Scale: A linear numbering scale used to define a logarithmic amplitude scale, thereby compressing a wide range of amplitude values to a small set of numbers.
Decimation: Suitable restructuring of data, for example swapping bandwidth (sampling frequency) for bit depth.
DECT: Digital Enhanced Cordless Telecommunications.
Delay: An audio effect that records an input signal and plays it back after a specified period.
Delay tower: A remote loudspeaker position time-aligned to the main system so distant listeners receive clearer sound at lower overall level.
Delta-Sigma Converter: Serial conversion at a high sampling frequency, where each bit specifies whether the current value of the signal is higher or lower than the prior one.
Depth: A spatial descriptor in audio assessment.
Detailed: A transparency descriptor in audio assessment.
DHCP: See Dynamic Host Configuration Protocol.
Dialnorm: An AC-3 metadata parameter, numerically equal to the absolute value of the dialog level carried in the AC-3 bit stream.
Dialog Level: 1: In audio/AV production: The loudness, in LKFS units, of the anchor element (see this).
Dialogue: Recording of the spoken voice for film.
Dialogue Matching: In film, dialogue matching is a process to make secondary recordings of dialog (from lavaliers, plant mics, a dubbing studio, etc.
Diaphragm: The thin membrane in a microphone or speaker that vibrates in response to sound waves.
Difference Frequency Distortion: Difference frequency distortion considers only the difference terms of intermodulation distortion.
Diffraction: The distortion of a wave front caused by the presence of an obstacle in the sound field.
Diffuse Field Response: The diffuse field response is significantly different from the on-axis response and shows the microphone's tonal qualities when placed in a highly-reverberant environment with a large distance to the sound sources.
Diffuse Sound: Sound that is completely random in phase; sound which appears to have no single source or direction.
Diffuser: A device that provides scattering when sound hits the surface.
Digital: Concerning a state wherein an electrical signal has been converted to a series of impulses according to a specific code.
Digital Audio Workstation, DAW: The DAW was initially a dedicated computer-based system for recording, editing, and mixing audio.
Digital eXtreme Definition (DXD): Most DSD (Direct Stream Digital, - for Super Audio CD) content is generated from a DXD master.
Digital Multiplex (DMX): A standard protocol for digital communication to remotely control intelligent lighting fixtures.
Digital snake: For PA/SR systems, the bus cable carrying digital audio signals between scene microphones and the mixer in the concert hall/venue.
Digital-to-Analog Converter (DAC): The device that recreates an analog signal after being represented by digital values.
DIO: Digital In/Out; digital input and output
Dipole Microphone: See Bidirectional Microphone.
Direct radiator: A loudspeaker where the sound shoots directly from the front of the cabinet, as the vast majority of studio monitors.
Direct Sound: In acoustics, sound radiated from a sound source and not affected by reflections.
Direct Stream Digital (DSD): DSD is a digital format that provides a high-resolution signal but works differently from the Pulse Code Modulation (PCM) system.
Direction of Arrival, DOA: Direction of Arrival applies predominantly to array microphones, where the DOA parameter is derived from the output of multiple microphones to estimate the direction of the sound source, for instance, to control the direction of a camera.
Directional Characteristics: Measure of the response of a microphone to sound incident from various angles or of the radiation pattern of a loudspeaker.
Directional Pattern: See Directional Characteristics.
Directivity Factor (DF): The directivity factor (DF or Q) refers to the ratio of the energy picked up on-axis to the energy picked up in all directions.
Directivity Index (DI): Directivity factor expressed in dB (10*log(directivity factor)).
Directivity Pattern: See Directional Characteristics.
Dissolve: Mixing (of images).
Distance: A localization descriptor in audio assessment.
Distance Double Law: When you double the distance from a point source, the sound pressure is halved (reduced by 6 dB).
Distance Factor (DSF): A microphone's distance factor (DSF or Q) roughly describes how far away one can position a directional microphone compared to an omnidirectional microphone to maintain the direct-to-diffuse field ratio.
Distorted: A signal-related descriptor in audio assessment.
Distortion: Any unwanted change in the original waveform of an audio signal.
Distortion Factor: Percentage measure for harmonic distortion, for example, k3 = 3% means that the third harmonic overtone is 3% of the fundamental tone.
Distortion, Harmonic: Changing the harmonic content of a signal by passing it through a non-linear device.
Distribution Amplifier: Amplifier that can distribute a signal to multiple inputs without the signal source becoming overloaded.
Dither: Noise added to a signal in the digital domain when reducing bit depth.
Diversity: True Diversity or Receiver Switching: In wireless microphone transmission, the principle that one receiver contains two separate antennas and two separate receiver circuits.
DME: Abbreviation for Dialog, Music and Effects, the three main components (stems) applied in audio for film.
DMX: Abbreviation for Digital Multiplex.
Dolby E: An audio data-rate reduction technology designed for use in contribution and distribution that also conveys Dolby E metadata.
Dolby® Digital TM: A lossy encoding scheme developed by Dolby Laboratories which greatly reduces the size of digital audio data by discarding information that, in theory, cannot be perceived.
Doppler Effect (Doppler Shift): The apparent upward shift in frequency of a sound as a noise source approaches the listener or the apparent downward shift when the noise source recedes (e.
Double MS recording: Where standard MS recording involves one cardioid microphone (pointing forward) and one figure-of-eight (pointing sideward), the double MS recording also includes a cardioid microphone pointing backward.
Downmix: To automatically extract a stereo or mono mix from a higher-order immersive format system like 5.
DRC: Dynamic range control.
DRC Profile: A collection of parameters that describe how dynamic range control metadata is calculated.
Drop-out: Short-duration loss of the signal on a tape due to faults in the tape's magnetic coating.
DSB: Digital satellite broadcasting.
DSD: See Direct Stream Digital.
DSP: Digital signal processor.
DTS: Digital Theater System.
DTS HD Master Audio: DTS-HD MA (known as DTS++ before 2004) is a multi-channel, lossless audio codec developed by DTS as an extension of the lossy DTS Coherent Acoustics codec (DTS CA; usually itself referred to as just DTS).
DTS:X / DTS:X Pro: DTS:X is an object-based surround sound technology that is a successor to DTS HD and a rival to Dolby Atmos.
Dubbing: Mix of one signal with another.
Dubbing Stage: In film, a dubbing stage is usually a studio facility that looks like a combination of a cinema and a recording studio.
Ducking: Automatic compression, for example when a speaker's insert dims the music signal.
Durability Factors: Important set of features for microphones.
DVD: Abbreviation for digital versatile disc or digital video disc.
DVD-Audio: A specialized type of DVD where most of the available storage space is dedicated to digital audio (as opposed to digital video) data, allowing for very high-fidelity sound.
DVD-Video: The most common type of DVD.
DXD: See Digital eXtreme Definition.
Dynamic Host Configuration Protocol (DHCP): Dynamic Microphone Dynamic Range
Dynamic Microphone: A rugged microphone that uses electromagnetic induction to convert sound into electricity.
Dynamic Range: Range between the quietest and loudest levels a device can produce or detect.

E

Earconography: A word created as an audio parallel to the visually based icon/iconography.
Early Decay Time (EDT): In room acoustics, the first 10 dB of the decay after the sound has stopped.
Earth: Another term for Ground (see this).
Earwitness: One who testifies or can testify to what he or she has heard.
EBS: A microphone setup developed by Eberhard Sengpiel of the Berlin University of the Arts.
EBU: European Broadcasting Union.
Echo: Sound impulse arising from a reflection with such a strength and time delay after the direct sound that it is perceived as a repetition of it.
Edge Track: Designation for the longitudinal (sound) tracks of a video tape, since these are located on the edge of the tape.
EDT: Early Decay Time (see this).
Effective Frequency Range: The frequency range at which the microphone does not deviate by more than a specific amount from the ideal/tailored response curve, i.
EFM: Eight-to-fourteen modulation.
EFP: Electronic Field Production.
EIAJ: Electronic Industry Association of Japan.
Eigen Mike: An array microphone that Meyer and Agnello developed in 2003.
Eigentone: (From German). 1.
EIN: Abbreviation for Equivalent Input Noise.
Electret Microphone: A condenser microphone with a permanently charged membrane/back electrode.
Electromagnetic Compatibility (EMC): An electronic or electrical product like a microphone must work as intended in its environment.
EMC: Electromagnetic Compatibility (see this).
Emphasis: A technique often used in analog transmission systems (wireless microphones, FM broadcast, etc.
Encode: The process of converting information (signal) into a coded form.
Encryption: A method used to encode signals (i.
End-Addressed Microphone: If placing the microphone capsule at one end of a tube-shaped housing, the on-axis direction is in line with the tube.
Envelopment: A spatial descriptor in audio assessment.
Equal Loudness Contour: A contour representing a constant loudness for all audible frequencies.
Equalizer, Graphic: Electronic equipment for "equalizing.
Equalizer, Parametric: Electronic equipment for "equalizing".
Equalizing: 1. The process that consists of modifying the frequency balance in the amplifier chain for the purpose of obtaining a flat frequency response, minimizing noise or achieving an artistic effect.
Equivalent Input Noise, EIN: In a microphone preamp, it is the noise at the output minus the gain.
Equivalent Noise Level: The equivalent noise level states the self-noise of the microphone either as an A-weighted RMS-level or as an ITU-weighted peak-level.
Ethernet: A computer network technology used in Local Area Network (LAN), Metropolitan Area Network (MAN), and Wide Area Network (WAN).
ETSI: European Telecommunications Standards Institute.
Expander: 1. Electronic equipment in which the output signal's dynamic range is increased in relation to that of the input signal.

F

F/X: See Special Effects.
Fade: A gradual change in the intensity of a sound.
Far End Audio: A term usually applied to networked audio.
Far Field: A region in free space at a much greater distance from a sound source than the linear dimensions of the source itself where the sound pressure decreases according to the inverse-square law (the sound pressure level decreases 6 dB with each doubling o
Far-field microphone: Microphone for use mainly at a distance of 1 m or more from the source of sound.
Farad, F: Farad is the SI-derived unit of electrical capacitance; the ability of a body to store an electrical charge.
FFT: Fast Fourier Transform.
File-based Scaling Device: A device used to apply an overall gain correction to audio content stored as files.
Filter: An electronic circuit or software process that removes specific frequencies from an audio signal.
Filter, Band Pass: A filter that passes all frequencies between a low-frequency cut-off point and a high-frequency cut-off point.
Filter, High-boost: A filter that amplifies frequencies above a specific frequency.
Filter, High-cut: A filter that attenuates frequencies above a specific cutoff frequency.
Filter, High-pass: A filter that passes all frequencies above a cutoff frequency but attenuates low-frequency components.
Filter, Low-cut: A filter that cuts off low-frequency signals below the cutoff frequency with a certain attenuation (roll off).
Filter, Low-pass: A filter that passes all frequencies below a cut-off frequency.
Filter, Notch: Narrow-band filter with very strong attenuation in a very narrow frequency range.
Filter, Octave: Filter with a bandwidth of an octave.
Filter, Shelving: A type of filter that gives constant amplification or attenuation from the corner frequency.
Filter, Third-octave: A filter whose upper-to-lower pass band limits bear a ratio of 2 1/3, which corresponds to 23% of the center frequency.
FireWire: FireWire is a digital interface connection standard intended for peripheral devices.
First-Order Pattern: See 1st Order Pattern.
Flanging: Sound effect based upon the direct signal mixed together with itself using varying time delays.
Floating Point recording: A technology where the converter's dynamic range automatically adapts to the level of the input signal.
Fluctuating / Intermittent: A signal-related descriptor in audio assessment.
Fold Back: The musicians on the scene have a need to be able to hear themselves and the others musicians in a quite specific manner.
Fold down: See Downmix.
Foley Artist: In the post-production and editing stage of a film's production, the foley artist (named after pioneer Jack Foley) creates or adds incidental sound effects/noises (e.
Foreground Sounds: Sounds that are required or appreciation of the program.
Formant: Voice: A resonance in the vocal tract.
Formant Bandwidth: The difference in frequency between the two half-power points (i.
Formant Tuning: In talking/singing: A boosting of vocal intensity when F0 (the fundamental frequency of the voice) or one of its harmonics coincides precisely with the formant frequency.
Forwarding and Queuing for Time-Sensitive Streams (FQTSS): A term that applies to the AVB (Audio Video Bridging) interface standard.
Free Field: An environment in which there are no reflective surfaces within the frequency region of interest and the sound is isotropic and homogenous.
Free-field Voltage Sensitivity: The ratio of the output open-circuit voltage of a microphone to the free-field sound pressure in an undisturbed plane progressive wave.
Frequency: The number of cycles per second, measured in Hertz (Hz) or 1000 Hz=kHz.
Frequency Band: A limited frequency range.
Frequency Range: The frequency range is also called the microphone "bandwidth".
Frequency Response: The frequency response of a microphone is the characteristic graph obtained by recording the level in dB of the output signal of the microphone, while the microphone is exposed to a certain acoustic field of pure sinusoidal tones with equal intensity
Frequency Shift Keying (FSK): In digital (radio) transmission, a method for modulating a digital signal onto an analog carrier.
Frequency Weighting: Modification of the frequency spectrum of a signal by means of a filter with a conventional characteristic known as A, B, C or D, RLB, CCIR/ITU, etc.
Fricative: A fricative is a consonant sound that is made when you squeeze air through a small hole or gap in your mouth.
Fricatives: Speech sounds produced by turbulence in a constriction of the vocal tract, such as an "s" produced with the teeth.
FSK: Frequency Shift Keying (see this).
Fukada Tree: The Fukada Tree is designed by the Japanese audio engineer Akira Fukada in 1997.
Full: A timbral balance descriptor in audio assessment.
Fundamental Frequency: The lowest frequency of a vibrating system.

G

Gaffer: In film production: The chief or head electrician or supervisory lighting technician in the film/photography crew on a movie set.
Gain: The amount of amplification applied to a signal at the input stage of a device.
Gain before feedback: The maximum useful system gain available before an acoustic feedback loop becomes unstable.
Gain Structure: The signal levels at different stages of a mixing console or a chain of audio devices.
Gate: See Noise Gate.
Gateway: A gateway is a piece of networking hardware or software used, for instance, in networks for wireless microphone transmission, allowing data to flow from one discrete network to another.
Gear: Encompasses all equipment.
Geophony: A term used in the soundscape definition of sound sources.
Giga (G): SI prefix giga (10^9) like in Ω (gigaohms).
Glitch: When a bit is skipped, it can lead to a little "crack" in the sound.
Glottal Stop: A transient sound caused by the sudden onset or offset of phonation.
Glottis: The airspace between the vocal folds.
Gooseneck: A flexible boom for microphones.
GPI: General Purpose Interface.
Gradient Microphone: A microphone where the directivity is determined by the difference (gradient) between frontal and rear input to the membrane.
Granular Synthesis: A technique of assembling (small) segments of recorded sounds – called grains – into new sounds.
Graphic Equalizer: See Equalizer, Graphic.
Ground: In electrical engineering (and audio engineering), “ground” or “earth” is the reference point in an electrical circuit from which voltages are measured, a common return path for electric current or a direct physical connection to the earth (via a con
Groundplane Antenna: A antenna with one director, vertical quarter-wave element, and three reflectors at 120°.
Group delay: Digital processing takes time.

H

Haas Effect: Also called the precedence effect or principle of first arrival.
Half-power Frequencies: The two frequencies on opposite sides of a resonant peak (or pass-band) where the power transmitted by a filter is half of its value at the peak (-3 dB re the top of the resonant peak).
Hamasaki Square: Microphone aray designed by the Japanese sound engineer Kimio Hamasaki.
Handling Noise: The sensitivity of a microphone to movement and shock.
Harmonic: A discrete sinusoidal (pure-tone) component whose frequency is an integer multiple of the fundamental frequency of the wave.
Harmonic Distortion: Changing the harmonic content of a signal by passing it through a non-linear device.
Harmonic Overtones: Tones with the frequency of an integer multiple of the fundamental frequency.
HDBaseT: A standard for transmitting ultra-high-definition video and audio, Ethernet, control signals, USB and up to 100 watts of electrical power over one long-distance cable (Cat 6 or higher).
HDMI: Abbreviation for High-Definition Multimedia Interface.
Head Related Stereo: Stereo techniques using human interaural geometry as a model for the microphone set-up.
Head Voice: A term used within vocal music, especially in classical singing.
Headroom: The safety margin between a signal’s normal operating level and the point where it begins to distort.
Hearing Level: A measured threshold of hearing at a specified frequency expressed in decibels relative to a specified standard of normal hearing.
Hemispheric microphone: A microphone mounted at a plane surface, accepting sound from a 180° angle.
Hertz, Hz: A unit of frequency measurement representing cycles per second.
Hexaphonie: A 6-channel format for picking up a sound sphere; developed by Madeleine Sola and Daniel Torsière at Radio France in the 1970s.
High Fidelity (Hi-Fi): As the name indicates, this designation has applied to good-sounding audio equipment for consumer use, i.
High-boost Filter: A filter that amplifies frequencies above a specific frequency.
High-cut Filter: A filter that attenuates frequencies above a specific cut-off frequency.
High-Pass Filter: A filter that passes all frequencies above a cutoff frequency but attenuates low-frequency components.
Higher-Order Ambisonics (HOA): The Higher-Order Ambisonics is a further development from Ambisonics, a recording format based on the soundfield microphone providing A-format or B-format signals .
Hissing: A signal-related descriptor in audio assessment.
HOA: Higher Order Ambisonics (see this).
Homogeneous: A timbral balance descriptor in audio assessment.
Horn loading: Using a flared acoustic path to improve the coupling between a driver diaphragm and the surrounding air.
House Sync: Sync signal that is distributed (in-house) so all digital devices can run at the same speed.
Hum Bucking: Hum bucking is a method to reduce induced electromagnetic noise (hum) in a dynamic microphone.
Humming: A signal-related descriptor in audio assessment.
HVAC noise: Heating, ventilation and air conditioning noise.
Hybrid: In audio, hybrid is a mixture of two technologies.
Hypercardioid Microphone: Normally regarded as a microphone with a directional characteristic between supercardioid and figure 8.
Hypocardioid microphone: Another expression for wide cardioid (or subcardioid).

I

iCheck: Integrity check.
IEC: International Electrotechnical Commission.
IEM: Abbreviation for In-Ear Monitor.
IFB: The term is an abbreviation for interruptible foldback.
IGMP: Internet Group Management Protocol.
ILD: Abbreviation for Inter-aural Level Difference IM IM Intermodulation (see this).
Immersive Audio: Immersive means totally surrounded by something – water, i.
Impedance: The total resistance to the flow of alternating current in an audio circuit.
Impedance Matching: Matching the impedance of an input with the impedance of an input.
Impulse Response: The response of a system to a unit impulse.
In-Band pink noise: Filtered noise used for test purposes, which could be 20 Hz to 80 Hz for a subwoofer, or 250 Hz to 2.
In-Phase: Two periodic waves reaching peaks and going through zero at the same instant are said to be in phase.
INA-3 or Ideal Cardioid Arrangement (ICA): This microphone technique was developed by Günther Theile.
Infrasound: Sound at frequencies below the audible range, i.
Ingress Protection Code (IPxxyz): This code clarifies and rates the degree of protection provided by mechanical casings and electrical enclosures against intrusion, dust, accidental contact and water.
Inherent Noise: Noise that is internally generated in a system in the absence of any excitation.
Initial Time Delay Gap (ITDG): The time gap between the arrival of the direct sound and the first sound reflected from the room's surfaces.
Insert: 1. Insertion of a clip (scene) in an existing recording.
Intensity: A measure of power per unit area [W/m^2].
Inter-aural Level Difference, ILD: The level difference between SPL at the left and right ear for a specific sound source position.
Inter-aural Time Difference, ITD: The difference in arrival time at the left and right ears for a sound source at a specific position.
Inter-channel Cross-correlation, ICC: Inter-channel Cross-correlation measures the similarity between signals in different channels, often by comparing a reference signal with a time-delayed version of another signal.
Interference Tube: An acoustically semi-transparent tube placed in front of a microphone capsule in order to achieve higher directivity.
Intermodulation: See Intermodulation Distortion (IMD).
Intermodulation Distortion (IMD): This occurs when two or more frequencies are supplied to a non-linear system.
Internality: An environment descriptor in audio assessment.
Interpolation: Computation of intermediate values in relation to fixed values (for example, values between two samples).
Inverse Square Law: A description of the acoustic wave behavior in which the mean-square pressure varies inversely with the square of the distance from the source.
IPv4: Present standard for Internet Protocol.
IPv6: A revised standard that provides far more unique IP-addresses compared to IPv4.
Isolation: Resistance to the transmission of sound by materials and structures.
ISRC: International Standard Recording Code.
ITDG: Initial Time Delay Gap (see this).
ITU: International Telecommunication Union.

J

Jack Plug: One-legged connector with two or three contacts.
Jack-bay: A patch panel with jacks that are used to make connections between different devices easy to establish.
Jam Sync: Method for recording new time codes from a source tape.
Jitter: Expresses that the sample timing in a digital stream deviates from the fixed rate.

K

K-weighting: The K-weighting applies to the loudness measurement of program material.
kbps or kb/s: Kilobits per second.
Keynote sound: In music, a keynote identifies the key or tonality of a particular composition.
kilo: SI prefix kilo (10^3) like in kΩ (kiloohms).

L

L-Cut: A digital film editing term, also known as a split edit, J-cut or delayed edit.
Lapel Mic: Another name for Lavalier Microphone (see this).
Larsen Effect: Acoustic feedback in electroacoustic systems, and also known as howl or just feed.
Laser Microphone: A microphone based on the optical reflections of a laser beam when hitting a vibrating object, like a loudspeaker membrane or window glass.
Latency: Elapsed time between an input event and its corresponding output, including conversion, buffering, processing, and propagation.
Lav Mic: Short for Lavalier Microphone (see this).
Lavalier Microphone: A microphone for speech that is attached to the clothing or worn around the neck.
Law of the First Wave Front: The first wave front falling on the ear determines the perceived direction of the sound.
Layback: A post-production technique where audio is rejoined with the associated video after editing, mixing or "sweetening".
LDC: Large Diaphragm Condenser (microphone).
LDR: Abbreviation for Loudness to dialog ratio (see this).
Leq: Equivalent continuous sound pressure level.
Leslie Effect: The Leslie Effect is based on the sound of a loudspeaker cabinet containing a rotary reflector above a fixed loudspeaker unit and a rotating horn assembly that together creates a swirling and pitch-shifting sound.
LF Equalizing Tube/Vent: A pressure microphone, in principle, consists of a diaphragm in front of a closed chamber.
LFE: Low Frequency Effects, see this.
Limiter: A dynamics processor that prevents an audio signal from exceeding a specific maximum level.
Line array: A vertically arranged set of closely spaced loudspeaker elements designed to couple over part of their operating range.
Line Driver: A unit used to transform high impedance (and eventually unbalanced) source lines (e.
Line Level: The standard signal strength used for connecting professional audio equipment, higher than mic level.
Line Spectrum: A spectrum that contains discrete (line) frequencies only.
Line-by-line mixing: Theatre mixing in which the operator opens each performer's microphone only for their lines and closes it immediately afterwards, to limit spill and comb filtering from many open omni mics.
Linear conversion: In digital audio: When each quantization step has the same size and the sampling frequency is constant.
Linear Phase Response: The phase is constant with frequency through the device or circuit.
Linear Pulse Code Modulation (LPCM): A method for the modulation of audio into a digital and lossless (linear) format.
Linear Quantization: In digital recording: Equal-sized steps used for the definition of the individual samples.
LKFS: LKFS is an acronym that stands for "Loudness, K-weighted, relative to Full Scale.
Load: The input of a microphone amplifier, mixer, etc.
Localizability: An environment descriptor in audio assessment.
Locate: To find a specific position, for example on a track, digital or analog.
Location Sound: Background sound on location, usually recorded separately for later adding to the final mix.
Lombard Effect: The Lombard effect is an involuntary tendency for a speaker to increase his or her vocal effort to enhance audibility when speaking in a loud, noisy environment.
Looping: 1. Infinite repeating of an (audio) sequence.
LoRo: Abbreviation for Left Only, Right Only.
Lossless compression: A bit-compression format that recovers all the original data from the compressed version.
Lossy Compression: A digital format that applies bit-compression and that cannot recover all of its original data from the compressed version.
Loudness Level: 1. In acoustics: measured in phons it is numerically equal to the median sound pressure level (dB) of a free progressive 1000 Hz wave presented to listeners facing the source, which in a number of trials is judged by the listeners to be equally loud.
Loudness to dialog ratio, LDR: In cinematic content, defined as the difference between Program and Dialog Loudness (LDR = PL − DL).
Low Fidelity (Lo-Fi): Applies to soundscape studies, where it expresses an unfavorable signal-to-noise ratio.
Low-Cut Filter: A filter that cuts off low frequency signals below the cut-off frequency with a certain attenuation (roll off).
Low-Frequency Effects: It is a particular recording channel containing 5 Hz to 120 Hz information primarily intended for special effects such as movie explosions.
Low-Pass Filter: A filter that passes signals below the cut-off frequency and attenuates the signal above that frequency.
Lower Limiting Frequency (-3dB point): The lower frequency at which the frequency response of a pressure microphone has fallen by 3dB.
LPCM: Linear Pulse Code Modulation (see this).
LTC: Longitudinal Time Code.
LtRt: Abbreviation for Left Total and Right Total.
LU / LUFS: Loudness Unit / Loudness Unit re Full Scale.

M

MAC: 1 Media Access Control is a unique address for a unit applied in a (digital) network.
MADI: Multichannel Audio Digital Interface also known as AES10.
Magnitude: The size of a signal.
Main Lobe: An expression related to the directivity pattern of antennas and microphones.
Mark: Clapping the sticks to synchronize the sound and the picture.
Masking: The process by which the threshold of audibility of one sound is raised by the presence of another (masking) sound.
Matching (of Microphones): Ensuring that all microphones in a stereo or a surround microphone kit perform to the exact same specifications.
Matrix: A device that can mix and distribute signals.
Max SPL: A specification of microphones.
Mbps or Mb/s: Megabits per second.
Measured Loudness: The magnitude of an audio signal when measured with equipment that implements the algorithm specified by ITU-R BS.
MEMS Microphone: MEMS is an abbreviation for Micro-Electro-Mechanical-Systems.
Meridian Lossless Packing, MLP: This data compression technique is designed especially for high-quality (96 kHz/24 bit) audio data.
META data: Additional data that goes with the core data of a file.
Metallic: In audio, sound production: Often, the perception of a metallic sound relates to comb filtering, where the signal is slightly delayed (ms) and added to itself.
Metaverse: The Metaverse is a digital copy of the real universe.
Meter: Designation for a measurement instrument for the control of signal levels.
Micro (µ): SI prefix micro (Greek letter µ) for a factor of one millionth, 10^-6, like in µm (micrometer).
MicroDot: A connector (coaxial, unbalanced) that applies to miniature microphones.
MicroLock®: A connector (coaxial, unbalanced) that applies to miniature microphones.
Microphone Array: See Array Microphones.
Microphone Level: The voltage output range of microphones with normal sensitivity, usually 1 mV – 50 mV.
Microsoft Multimedia Environment, MME: MME is a native Windows audio driver protocol.
Middle (or Mixed) Voice: The mixture between chest voice and falsetto; another term for "Head Voice" in singing.
Midfield monitors: Full-range studio speakers that are designed to be used free-standing.
MIDI: Musical Instrument Digital Interface.
Midrange Strength: A timbre descriptor in audio equipment or recording assessment.
Milli (m): SI prefix m (10^-3) like in mV (millivolt).
MIPS: Million Instructions per Second.
Mix (Mixing): The electrical combination of different audio sources.
Mixer: A device used to combine, route, and adjust the levels of multiple audio signals.
Mixing Level: Indication of the absolute sound pressure level calibration of the mixing studio that produced the content.
MKV: MKV files are multimedia container formats.
MLP: Meridian Lossless Packing, see this.
MMAD: Multichannel Microphone Array Design, see this.
MME: Microsoft Multimedia Environment (see this).
Mode: 1. A room resonance.
Modulation: An analog process by which the characteristic properties of a wave (the modulating wave) are mixed into another wave (the carrier wave).
Modulation Noise: Noise in the signal chain that varies with the signal strength.
MOL: Maximum Output Level.
Monitor: A control or monitoring device; in this context, a loudspeaker for the assessment of recording quality.
Mono: A single channel of audio where all sound is reproduced through one signal path.
Mono Compatible: A stereo signal, if no significant loss of level and no coloration (comb filtering) occur when summing the channels to one mono signal.
Moozak: Term applying to all kinds of schizophonic musical drool, especially in public places.
Mouse: A nickname for a Boundary Layer Microphone (see this).
MPEG: Motion Picture Experts Group.
MPX: Multiplex filter for removing an FM radio's stereo pilot tone.
MS Recording: A stereo recording technique that uses M (mid) and S (side) signals from one cardioid and one bi-directional (figure-of-8) microphone.
MSB: Most Significant Bit.
Multiband Transmitter/Receiver: In wireless transmission, a system that operates across two or more (UHF) frequency bands (8 MHz in Europe / 6 MHz in North America).
Multicell horn: A high-frequency horn divided into multiple flared cells to broaden horizontal or vertical coverage.
Multichannel Microphone Array Design, MMAD: Procedures to define microphone arrays for immersive recordings depending on mrecording space and microphone characteristics.
MVPD: Multichannel Video Programming Distributor.

N

NAB or NARTB: National Association of Radio and Television Broadcasters.
NAG: Needed Acoustic Gain.
Nanotechnology: Nanotechnology is science, engineering, and technology conducted at the nanoscale, about 1 to 100 nanometers.
Narrow-Band Spectra: Spectra that have been measured using a narrow frequency bandwidth.
Nasal: A timbre descriptor (midrange) in audio equipment or recording assessment.
Native: 1: Software that runs on a computer operating system that does not require additional hardware or software.
Natural: A transparency descriptor in audio assessment.
Natural Frequency: The frequency at which a system will vibrate when set into free vibration.
NBC: Non-backward compatible.
Near Field: That part of a sound field, usually within about two wavelengths from a noise source, where there is no simple relationship between sound level and distance.
Near-field microphone: Microphone for use by an individual performer at a distance of approximately 30 cm.
Ni-MH: Nikkel Metal Hydrid.
Nodes: The valleys in a standing wave pattern, where pressure or displacement is minimum.
Noise: Etymologically the word can be traced back to Old French (noyse) and to eleventh-century Provencal (noysa, nosa, nausa), but its origin is uncertain.
Noise Floor: The level of inherent background noise present in an audio system when no signal is being played.
Noise Gate: Special signal processing unit whose output signal is 0 until the input signal exceeds a specific, preset value.
Noise Shaping: A special technique providing frequency weighting of dither used in connection with reducing high resolution digital audio to a lower bit format.
NOS: Nederlandse Omroep Stichting (Dutch Broadcasting Foundation).
Notch Filter: A filter to reduce a very narrow frequency band by a steep dip.

O

OBA: Object Based Audio.
Object, Atmos: A discrete audio element that can be placed anywhere in the three-dimensional sound field, stationary or moving.
Object, gaming: In gaming, the objects are different from objects in audio.
OCT: OCT-3D Octaphony Octave Octave Filter Off-axis Response Ohm On-axis Response One-Bit Converter Open Sound Control (OSC) Open Systems Interconnection (OSI) Opening angle Operator Optical sound Optimized Cardioid Triangle, OCT ORTF OSC Oscillator OTA O
OCT-3D: An immersive audio recording microphone array based on OCT, with extra microphones for capturing depth and height.
Octaphony: A recording and reproduction format involving eight microphones distributed at equal distances on a horizontal circle.
Octave: A range of frequencies whose upper frequency limit is twice that of its lower frequency limit.
Octave Filter: A filter whose upper-to-lower pass band limit bears a ratio of 2.
Off-axis Response: Off-axis responses are normally submitted for directional microphones only.
Ohm: Unit for electrical resistance.
On-axis Response: The on-axis response is normally just referred to as the microphone's frequency response and will give information about the product's tonal behavior when placed close to the sound source.
One-Bit Converter: See Delta-Sigma Converter.
Open Sound Control (OSC): A protocol for networking sound synthesizers, computers and other multimedia devices for purposes such as musical performance or show control.
Open Systems Interconnection (OSI): A standardized model with seven steps that determines the communication in, for example, computer systems, regardless of their underlying internal structures and technologies.
Operator: A broadcast network, broadcast station, DBS service, local cable system or cable multiple system operator (MSO).
Optical sound: The sound is printed using a photographic process on 35- or 16-mm film.
Optimized Cardioid Triangle, OCT: OCT is a surround sound microphone technique developed by Günther Theile and Helmut Wittek for the front microphone array.
ORTF: Office de Radiodiffusion Télévision Française (French Radio and Television Office).
OSC: Abbreviation for Open Sound Control.
Oscillator: Signal generator for the generation of, for example, pure sinusoidal tones with constant amplitude for use in measurements.
OTA: Abbreviation for Over The AIR.
OTT: Over The Top: The means to deliver video content via streaming, Video On Demand (VOD), Pay TV, IPTV and download via IP mechanisms.
Output Impedance: The alternating current resistance a circuit's output represents.
Ouverture: The opening music of an opera presents small excerpts of the music that the orchestra and the singers will perform later in the performance.
Overdrive: 1. An audio effect basically applied with guitar sound.
Overdub: A process whereby a track is recorded while listening to already recorded material on the same or a different tape recorder.
Overhead Microphones: Placing microphones above the sound source in order to pick up more ambience with the instrument.
Oversampling: The use of a sampling frequency that is a number of times higher than is necessary.
Overtone: A harmonic frequency component of a complex tone at a frequency higher than the fundamental.

P

P48: Phantom power see this providing 48-volt DC for the microphones through the XLR connection.
PAC: Perceptual Audio Coding.
Packet Transmission: Transmission of standardized data packets over transmission lines or networks of high-speed switching computers.
Pad: Circuit in the input module (for example, in a mixer) with the purpose of preattenuating the signal.
Pan-Pot: Potentiometer in the mixer for "moving" the signal between the left and right channel.
Parabolic Microphone: A microphone element positioned at the focus point of a parabolic screen, which provides amplification of distant sources.
Parallel Port: Digital input or output port with multiple lines, allowing multiple bits of data to be transferred simultaneously.
Partial: One of a group of frequencies, not necessarily harmonically related to the fundamental, which appears in a complex tone.
Pascal Pa: A unit of pressure corresponding to a force of 1 Newton acting uniformly upon an area of 1 square meter.
Pascal's Law: Pressure is transmitted rapidly and uniformly throughout an enclosed fluid at rest.
Passaggi (Italian): Passages on a pitch scale where the voice tends to change register involuntarily.
Passband: Passband is the description of the frequency range that an electrical filter passes.
Patch: Connection of circuits via external connections.
PCM: Pulse-code Modulation.
PDM: Pulse Density Modulation.
Peak: The maximum positive or negative dynamic excursion from zero of any time waveform.
Peak-Hold: Circuit that for a shorter or longer period of time is in a position to maintain a peak value display on an instrument.
PEAQ: Perceptual Evaluation of Audio Quality.
Pencil Microphone: A microphone form-factor in which a tube-shaped housing contains a microphone element in one end and a connector in the other.
Perceived Loudness: A loudness descriptor in audio assessment.
Perceptual Coding: A principle for low bit rate coding based on the ear's masking abilities.
Periodic Signal: A signal is periodic if it repeats the same pattern over time.
Phantom Powering: A technique for supplying the preamplifier supply voltage to condenser microphones whereby half of the d.
Phase: The relative timing of two sound waves, which can cause cancellation if they are out of sync.
Phase Spectrum: A display of the relative phases versus frequency of a waveform component.
Phase-Shift Keying, PSK: In digital (radio) transmission, a method for modulating a digital signal onto an analog carrier.
Phon: The loudness level of a sound.
Phono Plug/Jack: Plug and jack for one conductor and shielding.
Piezoelectric microphone: See crystal microphone.
Pink Noise: A random sound signal containing equal energy per octave, often used for acoustic testing.
Pitch: The attribute of auditory sensation that orders sounds on a scale extending from low to high.
Plane wave: A plane wave is a constant-frequency wave of which the wavefronts (surfaces of constant phase) are infinite parallel flat planes perpendicular to the direction of propagation.
Plant Mic: A small microphone for hiding in a fixed place on set.
PLL: Phase-locked Loop.
Plosive: A transient speech sound generated by a sudden onset or offset of air movement in the vocal tract.
Plosives: A plosive speech sound.
PoE: Power over Ethernet.
Point Source: A source whose dimensions are small compared to the propagation distances described in reference to it.
Polar pattern: A map of a microphone or loudspeaker’s sensitivity or output as a function of angle.
Polar Plot: The graphical representation of the microphones directional behavior at different frequencies.
Polarity: Referring to the positive or negative direction of a signal.
Polarization Voltage: The (normally high) DC voltage applied to the backplate-diaphragm capacitor of a condenser microphone via a high resistance, thus setting up a fixed charge condition.
Popping: Noise associated with the vocally-induced distortion in a microphone due to consonant sounding, "p", "b", "t" etc.
Post Production: The entire post-processing phase (including editing, sound effects, music, etc.
Potentiometer: Adjustable resistance used, for example, in controlling levels.
Power: Source of energy.
Power Spectral Density (PSD): PSD is the total signal power in a specified spectral bandwidth divided by the bandwidth (watts/hertz).
Powerful: A dynamics descriptor in audio assessment.
PPM: Peak Program Meter.
Pre-conditioning: Microphones are pre-conditioned by being switched on/connected for a period of time before using them.
Pre-delay: Pre-delay is a parameter found in reverb processors.
Precedence Effect: See Haas Effect.
Prefix: A word, letter or number placed before another.
Prepolarization: A technique of depositing a fixed charge-carrying layer on either the diaphragm or backplate of a condenser microphone, thus eliminating the need for an external polarisation voltage.
Presence: The frequency range around 2-5 kHz.
Pressure Microphone: A microphone in which only one side of the diaphragm is exposed to the impinging sound.
Pressure Zone: As sound waves strike a solid surface, the particle velocity is zero at the surface and the pressure is high, thus creating a high-pressure layer near the surface.
Pressure-Gradient Microphone: A microphone in which both sides of the diaphragm are exposed to the incident sound and the microphone is therefore responsive to the pressure differential (gradient) between the two sides of the membrane.
Primo Passagio (Italian): "The first passage"; the first register change perceived in a voice.
Program loudness (PL): The integrated loudness over the duration of a program; Program Loudness Level is the value (in LUFS) of Program Loudness and is measured with a loudness meter compliant with ITU R BS.
Programme Making and Special Events (PMSE): A term related to wireless transmission and the occupation of RF spectrum.
Proscenium: The part of a stage in front of the curtain; the framework around a traditional theatre's stage opening.
Proximity Effect: An increase in low-frequency response that occurs when a directional mic is placed very close to a source.
PSD: See Power Spectral Density.
PSE: Power Sourced Device.
PSK: Phase-Shift Keying (see this).
Psychoacoustics: The study of the interaction of the human auditory system and acoustics.
PTP: Precision Time Protocol, used to synchronize clocks across a network with high accuracy.
Punch: A dynamics descriptor.
Punch-In: A rerecording of a short sequence in an already recorded program.
PZM - Pressure Zone Microphone: PZM(TM) microphones or boundary layer microphones are taking advantage of special acoustic phenomenons occurring at the surface of a boundary.

Q

Q factor: Measure for the slope of a resonance top.
QoS: Quality of System.
QPSK: Quadrature Phase-Shift Keying (see Phase-Shift Keying).
Quantization: Digitalization of a signal.
Quasiperiodic: An imprecise term which is sometimes used to suggest a small deviation from periodicity.

R

Radio Wave: Electromagnetic waves in the frequency range of 3 kHz – 300 GHz.
Random Access Memory (RAM): Digital storage where data can be arbitrarily stored and retrieved.
Rated conditions: When testing a microphone according to IEC standard, the microphone should be brought under rated conditions.
Rated impedance: It is the impedance that is specified by the manufacturer.
Rated minimum load impedance: It is usually an impedance specified by the manufacturer.
Rated sensitivity: In the IEC standard, the rated sensitivity is the free-field, diffuse-field, close-talking, or pressure sensitivity of the microphone assigned by the manufacturer.
Reach (of a microphone): The distance at which the microphone no longer picks up the sound of a sound source due to the masking effect of the self-noise.
Reciprocity Calibration: A method for the primary calibration of condenser pressure microphones, 1 inch and ½ inch measurement microphones, in particular.
Recording Angle: In stereo recording, the angle subtended by the sound source required for a speaker-to-speaker stereo spread.
Red Book: The official audio CD (CD-DA) specification, which includes definitions of sample rate (44.
Reference point: When measuring a microphone the microphone’s reference point is defined.
Refraction: The bending of a sound wave from its original path, either because it is passing from one medium to another with different velocities or due to changes in the physical properties of the medium, for example, a temperature or wind gradient in the air.
Registers: Perceptually distinct regions of vocal quality as pitch or loudness are changed.
Remote Miking: Placement of a microphone at a distance from the source, thereby picking up a larger proportion of the reflected sound.
Renderer: A processor that converts object positions and system geometry into signals for physical loudspeakers.
Repurposing: A term used to describe the reformatting of existing recorded music; i.
Resolution: Regarding a digitized signal: The number of bits per sample.
Reverberance: An environmental descriptor in audio assessment.
Reverberation: The persistence of sound in a space after the original source has stopped, caused by multiple reflections.
Reverberation Time: The time, in seconds, required for sound pressure at a specific frequency to decay a specified amount after a sound source is stopped.
RF Power: The power radiated from a transmitter.
RFI: Radio Frequency Interference.
RFoF: Abbreviation for Radio Frequency over Fiber.
RIAA: Abbreviation for Radio Industry Association of America.
Ribbon Microphone: A dynamic microphone in which the diaphraghm is a conductive ribbon in a magnet slit.
RIFF: The wave file format (*.
Rifle Microphone: Previously, the term used for Shotgun Microphones / Interference Tube microphones.
Rig: Touring shorthand for the complete loudspeaker, amplification, processing, cabling, and support system.
Rigger: A production person on a music stage or film set, who sets up lighting equipment, loudspeakers, scaffolding, etc.
RMS: A measurement of the average power level of an audio signal.
Roll Off: The attenuation of a high-pass or low-pass filter is called roll off.
Room Mode: The normal mode of vibration of an enclosed space.
Root Mean Square (RMS): The square root of the arithmetic average of a set of squared instantaneous values.
Rough: A signal related descriptor in audio assessment.
Routing Switch: A switch for the routing of signals.
RT60: Reverberation time based on the 60 dB attenuation of the sound after the sound source has stopped.
Rubbing: A signal related descriptor in audio assessment.

S

S/N: See Signal-to-noise Ratio.
SACD: Abbreviation for Super Audio Compact Disc.
Sample Rate: The number of times per second that an analog signal is measured to create a digital representation.
Sample Rate Converter: Converts digital signals with the same reference from one sampling frequency to another.
Sampling: In digital technology: Entry of the signal into discrete values in a table.
Sampling Frequency: The number of samples that are extracted per second.
Satellite speakers: A term used by some consumer electronics systems to describe the small speakers in 5.
Schroeder Diffuser: This is a sound-diffusing panel based on a square residual value sequence for scattering sound reflections, usually in one or two dimensions (horizontal/vertical).
SCSI: Small Computer System Interface.
SDC: Small Diaphragm Condenser (microphone).
SDDS: Sony Dynamic Digital System.
SECAM: Systeme En Couleur Avec Memoire.
Second-Unit Audio: In larger film and video productions, this refers to the less critical scenes (large crowd scenes, foreign location backgrounds, various inserts, etc.
Secondo Passagio (Italian): "The second passage", the second register change perceived in a voice.
SeDAC: Sennheiser Digital Audio Codec, a codec invented for wireless long-range transmission systems.
Self-noise: The internal electrical noise generated by a microphone’s own circuitry.
Self-sustained Oscillation: An oscillation that continues indefinitely without an external driving force; since the net energy loss per cycle must be zero, self-oscillation requires an internal energy source.
Sensitivity: Acoustic output produced for a stated electrical input, normally measured at a specified distance.
Separation: Degree of signal-related separation between tracks, channels, etc.
Sequencer: A device on which information about sequences can be recorded, but not the sequence itself.
Shelving Filter: A type of filter that gives constant amplification or attenuation from the corner frequency.
Shimmer: Short-term (period to period) variability in amplitude.
Shock Mounting: Any system mounting or suspension which mechanically isolates equipment from unwanted vibration.
Shotgun: A directional microphone utilizing an interference tube.
Show file: The saved console session holding a production's channel names, cue list and processing, often prepared offline and updated daily during rehearsals.
Shrill: A signal related descriptor in audio assessment.
Shuttle Mode: As related to tape transport or DAW track handling: The running of the recording back and forth between two points.
SI Units: International System of Units (Système international d’unités).
Sibilance: Noise associated with vocal sounding of words with characteristically "s", "sch", or "ch" syllables.
Side addressed microphone: A microphone that picks up sound from the side, rather than the end (given the microphone has a cylindrical shape).
Side Lobe: 1. Off-axis coloration components often seen (or rather heard) on shotgun mics.
Side Lobes: An expression related to the directivity pattern of antennas and microphones.
Sidefill: A stage-monitor loudspeaker covering performers across the width of the stage.
Signal-to-Noise Ratio (S/N or SNR): The ratio of the maximum signal that a system can record or reproduce to the inherent noise of that system.
Sine: In audio, sine is a tone containing only one frequency.
Sinusoidal Tone: The most simple harmonic tone, consisting of only one frequency.
Slap Back: A discrete reflection from a nearby surface.
Slating: Marking on a recording before a take.
Slope: In audio, the slope describes: 1.
Snake: For PA systems, the bus cable between scene microphones and the mixer in the concert hall.
SNR: Signal-to-Noise Ratio (see this).
SOL: Saturation Output Level.
Sonic Character: 1. Characteristics of sound as defined from attributes like “cold/warm,” “dark/light,” “cloudy/detailed,” “closed/open,” “skewed/balanced”, etc.
Soniferous garden: A garden, and by analogy any place, of acoustic delights.
Sonography: The art of soundscape notation.
SOR: Source Oriented Reinforcement (see this)
Sound: Energy that is transmitted by pressure waves in air or other materials and is the objective cause of the sensation of hearing.
Sound Absorption Coefficient: The practical unit between 0 (no absorption) and 1 (full absorption) expressing the absorbing properties of a material.
Sound Card: A sound card is an interface between an audio source – like a microphone – and a computer.
Sound Field Microphone: A single unit microphone with four cardioid condenser microphone capsules shaped like a tetrahedron.
Sound Level Meter: An electronic instrument for measuring the RMS level of sound, usually in accordance with an accepted national or international standard.
Sound object: 1: Sound object: Pierre Schaeffer, the inventor of this term, describes it as an acoustic "object for human perception” and not a mathematical or electro-acoustical object for synthesis.
Sound Pressure: The instantaneous difference between the actual pressure produced by a sound wave and the average barometric pressure at a given point in space.
Sound Pressure Level (SPL): A physical measurement of the intensity of sound waves in the air, expressed in decibels.
Sound Propagation: The sound's spread in space.
Sound Wheel: The Sound Wheel has been developed by SenseLab (of FORCE, Denmark) for the purpose of listening tests.
Soundstage: For film and TV: A large, soundproof area in a studio that allows greater control over the acoustics, lighting, air conditioning and audiences.
Soundtrack: In music recording: One or more synchronized tracks on tape or disc that form the full recording when mixed.
Source-filter Theory: In voice science: A theory that assumes the time-varying glottal airflow to be the primary sound source and the vocal tract to be an acoustic filter of the glottal source.
Spatial Audio: The expression has slightly different meanings depending on the format: The listener is enveloped by sound and can easily and accurately localize it.
Speaking Registers: In voice science, it refers to pulse, modal and falsetto.
Special Effects: A broad, wide-ranging term used by the film industry, meaning to create fantastic visual and audio illusions that cannot be accomplished by normal means, such as travel into space.
Spectral Slope: A measure of how rapidly energy decreases with increasing frequency or, for periodic waveforms, with increasing harmonic number.
Spectral Slope Transition: An abrupt voice-quality change that results from an abrupt acoustic change, specifically from sudden loss or gain of high-frequency sound energy at the source.
Spectrum: In audio, usually understood as the spectrum of frequencies, a display of relative magnitudes of phases of the component frequencies of a waveform.
Speed of Sound: The table shows the difference in the speed of sound between air and water, different temperatures and between fresh and salt water.
Spherical Wave: A sound wave in which the surfaces of constant phase are concentric spheres.
Splay angle: The physical angle between adjacent loudspeaker cabinets or horn axes.
Splitbox: A unit that distributes the signal from a microphone to multiple mixers or tape recorders.
Sprocket hole: Small rectangular holes located on both sides of a photographic film (or one side on a 16 mm or 8 mm film).
Square Wave: Waveform for acoustic or electrical signals that, in terms of frequency, contain a fundamental tone and all the odd-numbered harmonics.
Squelch: In a receiver for analog wireless transmission: A function to mute the audio if the signal is too noisy.
Stacked Converters: In digital technology, the principle to apply two converters to cover a dynamic range that is too high for one converter.
Standard Deviation: If the instantaneous distances from an equilibrium position of a vibrating body are squared and averaged, the result is called the variance of the vibration.
Standard Deviation (SD): In mathematics, the standard deviation (or σ) is a measure of how dispersed the data is in relation to the mean.
Standing Wave: A periodic wave having a fixed distribution in space which is the result of interference of progressive waves of the same frequency and kind.
Stems: In music production, stems are sub-mixes of a more extensive mix that will recreate the full mix when played together at an equal level.
Stereo: A two-channel audio system that creates a sense of spatial width and direction.
STI: Speech Transmission Index.
Stopband: A band of frequencies rejected by a filter.
Streaming Audio: Sound that can be played back immediately in (almost) real time from the Internet.
Sub Harmonic: Sub harmonics are synchronous components in a spectrum that are multiples of 1/2, 1/3, or 1/4 of the frequency of the primary fundamental.
Subcardioid Microphone: Another word for a wide cardioid microphone.
Subnet: A subnetwork, or subnet, is a logical subdivision of an IP network.
Super Audio Compact Disc (SACD): Optical media for storage of stereo and surround sound.
Supercardioid Microphone: A microphone with a frontal opening angle of 57 degrees, a dead angle at 126 degrees and some sensitivity to the rear.
Supersonic: See Ultrasound.
Surround Sound: A sound production format including multiple channels and loudspeakers to be placed around the listener.
Sweet Spot: The optimum listening position in front of the stereo or surround speakers.
Symmetry Attenuation: The attenuation of induced electrical noise signals that is attained in a balanced connection.
Synchronizer: A unit that, by the use of a time code, can deliver control signals for the time-related locking of, for example, tape units.
Synchronous Sound: In film: The sound from a source that is visible in the image's frame.
System controller: Dedicated processing that applies crossover, equalization, delay, and protection for a loudspeaker system.

T

Tailored frequency response: A frequency response that is shaped (non-flat) on purpose to enhance the sound for a particular application.
Tails out: A method of winding audio recording tape before storage.
Take: A single, continuously-recorded version of a film scene or music sequence.
Talkback microphone: A microphone used in a talkback system that allows the engineer or producer in the studio control room to communicate with musicians in the studio.
Talkies: The common popular term used for films with sound, (beginning in 1923 with engineers Petersen and Poulsen) as opposed to silent films.
Tape Delay: A delay created by using a tape recorder to produce what is called a slapback echo or slapback delay.
Tape Speed: The speed at which a magnetic tape passes the magnetic heads in a sound or video tape recorder.
Taping: Outlet from mixer channel, for example aux-send.
Target Loudness: A specified value for the anchor element (in some systems dialog level), established to facilitate content exchange from a supplier to an operator.
TDIF: Tascam Digital Interface.
Telemetry: Operational data returned by system devices, such as temperature, load, faults, or limiter activity.
Telephone Hybrid: Unit that adapts a telephone to a mixer console.
Tessitura (Italian): Texture; the average pitch level of a song or a part of a song in relation to the overall range of the instrument.
TetraMic: A microphone that is basically similar to the soundfield microphone.
THD+N: Total Harmonic Distortion plus Noise.
Third-Octave Band: A frequency band whose cut-off frequencies have a ratio of 2 1/3, which is approximately 1.
Thunderbolt: Thunderbolt is a digital interface connection standard intended for peripheral devices.
Tie-Line: Connection line for signals (for example, between editing rooms).
TIM: Transient Inter Modulation distortion.
Timbre: The quality of a sound related to its harmonic structure.
Time Code (TC): Digital code that marks time with information on frames, seconds, minutes, hours, etc.
Time Constants: In electronics (and therefore in audio), a time constant τ is defined by the time it takes to charge a condenser C to approximately 63% of its full value by a feeding resistor R.
Time Difference Stereo: A spaced microphone stereo recording technique which uses left versus right time and phase differences of the acoustic signals to give cues which project to the listener a vivid stereo image.
Tinnitus: Ringing in the ear or noise sensed in the head typically caused by excessive exposure to high sound levels.
Tinny: A timbre descriptor (treble range) for the assessment of audio equipment.
Tonmeister: A German title for an academically-educated sound engineer.
Total Harmonic Distortion (THD): Distortion in non-linear systems where harmonic components (integer multiples of a fundamental frequency) are produced.
Trackability: The comparative phase response of a microphone pair.
Transducer: A device that converts energy from one form to another; microphones and loudspeakers are reciprocal examples.
Transfer function: A comparison of a known reference signal with the measured system output, showing changes in magnitude and phase.
Transformer: An electronic device consisting of two or more coils used to couple one circuit to another.
Transient: A short, high-energy peak at the beginning of a sound, such as a drum hit.
Treble Strength: A timbre descriptor for the assessment of audio equipment.
Trim: In audio: To adapt the incoming signal to the sensitivity of the input circuitry, for instance, adjusting the signal from a microphone to a mixer input.
True Peak, TP: The maximum absolute level of the signal waveform in the continuous time domain, measured per ITU-R BS.
Truncation: Cutting off of superfluous bits without weighing their value.
Tube Microphone: 1. A (condenser) microphone that uses a built-in electronic tube for impedance conversion and amplification.
Turbulence: Irregular movement of air.
TV channel: The UHF frequency range is split into a number of bandlimited frequency ranges, each containing one TV channel.
Twisted Pair: A way to ensure balancing in cables.
Two-Way Microphone: A microphone that includes two capsules to pick-up low and high frequencies, respectively.

U

UHF: Ultra High Frequencies.
Ultrasound: Sound at frequencies above the audible range, that is, above about 20 kHz.
Unbalanced: A connection where the chassis/ground is a part of the circuit carrying between electro acoustic devices.
Unidyne: A name given to a specific single-capsule, dynamic, directional microphone from Shure (Model 55).
Universal players: Devices that can play CDs as well as SACDs and the two kinds of DVDs, DVD-Audio and DVD-Video.
Unwrapping: A commonly used term to describe the use of a digital processor or computer program to automatically upmix a stereo signal to 5.
Upmix: A technique for the automatic creation of a higher number of audio channels for immersive reproduction of recordings initially recorded in a format with a lower number of channels.
User Datagram Protocol (UDP): In computer networking, the UDP is one of the core communication protocols to send messages transported as datagrams in packets to other hosts on an Internet Protocol (IP) network.
UTP: Unshielded Twisted Pair.

V

V2MA: V2MA" most commonly refers to the ReSpeaker Mic Array v2.
Variable-D®: A unique design of a cardioid microphone implementing Variable Distance to the diaphragm's rear.
Varispeed: Variable speed, generally in playback systems.
VBAP: Abbreviation for Vector Based Amplitude Panning
VCA: Voltage-Controlled Amplifier.
VCR: Video Cassette Recorder.
Vector-Based Amplitude Panning, VBAP: A methodology applied to immersive audio reproduction.
VHF: Very High Frequency.
Virtual Reality (VR): VR is a computer-generated artificial environment experienced through sensory stimuli, usually presented in VR headsets containing glasses/screens and headphones.
Virtual Sound Check (VSC): Recording the live multitrack files from a band either during a performance or during soundcheck and then playing those recorded files back through the console and down their respective channels.
Virtual Studio Technology (VST): VST is a plug-in format introduced in 1996 by Steinberg for integrating plug-ins with digital audio workstations (DAWs).
Vocal Folds: A paired system of tissue layers in the larynx that can vibrate to produce sound.
Vocal Tract Resonance: Constructive interference (reinforcement) of waves experiencing multiple reflections in the vocal tract.
Voice Range Profile: A visual display of vocal intensity range versus fundamental frequency.
Voiceover: 1. Recorded dialogue, usually narration, that comes from an unseen, off-screen voice, character or narrator.
Volt (V): Unit for voltage measurements.
Volumetric audio: A method for manipulating spatial sound to provide information on the sound sources’ position.
Vowel: 1. A speech sound produced by vibrating vocal cords.
Vpp: Measure of the magnitude of an electrical voltage from peak to peak.
VSC: Virtual Sound Check (see this).
VST: Virtual Studio Technology (see this).
VSTi: VST Instruments, a VST format to generate audio using virtual synthesizers or samplers.
VTR: Video Tape Recorder.

W

WAM: Abbreviation for Women’s Audio Mission, a nonprofit organization dedicated to the advancement of women/girls/gender-expansive individuals in music production and the recording arts.
WASAPI: Windows Audio Session Application Programming Interface (see this).
Watt (W): The unit of electrical or acoustical power.
WAV: Waveform Audio File Format.
Wave Impedance (acoustic): In a sound propagating medium, the ratio of acoustic pressure to the speed of air particles is driven by this pressure.
Waveform: A plot of any variable (e.
Wavefront: The initial disturbance in a propagating wave.
Wavelength: The distance measured perpendicular to the wavefront in the direction of propagation between two successive points in the wave separated by one period.
WaveRT: (Wave Real-Time).
Weighting: Adjustment of the time or frequency response of a measuring device to achieve a desired prescribed filtering.
Weighting Network: An electronic filter which gives different weighting to signals at different frequencies, commonly to approximate the frequency response of the human ear under defined conditions.
Wente microphone: This condenser microphone was invented in 1914 and patented in 1916 by E.
Whip antenna: An antenna, typically used for wireless transmitters (beltpacks).
Whisper: Sound created by turbulent glottal airflow in the absence of vocal fold vibration.
White Noise: A random sound signal with equal energy at all frequencies across the audio spectrum.
Whoop-Whoops: When editing sound effects, this refers to the extra noises added to a sound, to increase interest or excitement.
Wide Cardioid Microphone: A microphone that has a directional pattern between an omnidirectional and a cardioid.
Wideband: Describing frequency range.
Width: A spatial descriptor in audio assessment.
WILM: Abbreviation for Women In Live Music, a European platform and online community for women working backstage in live music; this includes Sound Engineers, Tour Managers, Lighting Designers, Riggers, Backliners, Stage Managers, Stagehands, Truck Drivers
Windows Audio Session Application Programming Interface, WASAPI: WASAPI is a driver that enables DAWs and other audio applications to manage the flow of audio data between the application and a device for Windows 7 and higher.
WMAS: Wireless Multi-Channel Audio Systems is a wireless broadband audio technology that can combine wireless microphones, instruments, in-ear monitors (IEM) and remote controls into one broadband RF channel.
Word length: See Bit resolution.
Working Level: The signal level at which a circuit is nominally modulated.
Wow: In audio recorders or reproducers: Variation in speed, audible if >± 0.
WPAN: Abbreviation for Wireless Personal Area Network.
WRMS: Weighted RMS value.

X

X curve: This is the name for an equalization curve for the cinematic B-chain (amplifier, loudspeakers and room).
XLR: A professional three-pin connector commonly used for balanced microphone and line-level signals.

Y

Y-split: Typically a physical cable with one female XLR and two male XLRs connected in parallel.

Z

Zoom Microphone: The zoom microphone design is developed to be used with cameras to follow the zoom of the lens.
Zwicker loudness: A method for expressing the loudness of complex sounds.

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1876–1915Origins of electrical sound 1915–1945The public-address age 1945–1965Postwar fidelity goes portable 1965–1975The rock-concert revolution 1975–1990The modular touring machine 1990–2005Digital control and the line array 2005–2018The networked system 2018–presentImmersive and intelligent systems

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