A/B testing is a method used in marketing and product development to compare two versions of something, like a webpage or an app, to see which one performs better. Essentially, you show version A to one group of users and version B to another, then measure which version gets a better response. It helps businesses make data-driven decisions by testing variations and optimizing for better results.
A-D
Analog-Digital.
A-filter
See A-weighting.
A-Format
A microphone arrangement with four coincident cardioid capsules. Using a dedicated matrix, this signal can be converted to B-format. See Sound Field Microphone.
In film or video projects, A-roll is all the main footage, basically shot by an A-camera. The B-roll refers to any footage shot by a B-camera or any other supplemental footage to the A-roll. In larger productions with more photographers or filming crews, the crew shooting the B-roll is usually called the "Second unit".
A-weighted Sound Pressure Level
Sound pressure level measured with an A-weighting function involved. (See A-weighting).
A-Weighting
A-weighting is a filtering or a filter function inserted in the signal chain. It applies in particular to the measurement of acoustic noise at the workplace and the environment. However, it also applies to the measurement of noise in microphones. To some degree, the A-weighting filter mimics the frequency response of the human ear at lower levels (the 30 phon equal loudness curve) (see Equal Loudness Contour).
B- and C-weighting curves belong to this family of curves; however, these were developed to be used at higher levels.
A-weighting is specified in IEC 60 651, but references are also made in other standards like ANSI S1.4-1981.
Measurements performed with A-filters are often described with an "A" in parentheses, for example, xx dB(A) or with an "A" as an index, LA = xx dB.
In production for theatre: A1 is the person that makes the audio mix. A2 is usually the backstage assistant who performs cable checks, mic placement, etc.
AAC
Advanced Audio Coding. Special variant of the MPEG standard.
AB
1. A microphone setup for time difference stereo.
2. A method for powering microphones (±12 volt on the signal leads), also called Tonader.
3. A method for comparison of two versions.
(symbol: α) The practical unit between 0 (no absorption) and 1 (full absorption) expressing the absorbing properties of a material. This is basically specified per octave or 1/3 octave. Absorption may exceed 100% (or a >1) when the surface area seems larger than the area it covers (applies typically only at high frequencies).
Acoustic equalizers or acoustic pressure equalizers (APEs) are sphere-shaped accessories designed for use with omnidirectional microphones. They result in higher directivity in the upper part of the frequency range and an upper midrange frequency boost.
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 sound reaching the backside of the diaphragm). Schoeps has been especially clever using this principle for single-diaphragm microphones.
Active Drive
Active drive is a technology implemented in microphone preamplifiers.
Electrostatic actuators are used to simulate the pressure response of condenser microphones. This is done by exerting an oscillating electrostatic force in front of the microphone's diaphragm and measuring the subsequent response of the microphone.
ADC
Analog to Digital Converter (see this).
ADPCM
Adaptive Differential Pulse Code Modulation (see this).
ADR
Automatic Dialog Replacement (see this).
AES
Audio Engineering Society (see this).
AES/EBU
AES/EBU The AES (Audio Engineering Society) and EBU (European Broadcast Union) created jointly a standard for the transfer of two channels of digital sound. The signal is bi-phase modulated, self-clocking and runs on a balanced cable (max. 50 m or 150 ft) or via optical fiber. The standard currently is called AES3.
AES67
AES67 is a technical standard for audio over IP (AoIP) and audio over Ethernet (AoE) interoperability. The standard was developed by the Audio Engineering Society and first published in September 2013. It is designed to allow interoperability between various IP-based layer 3 audio networking systems such as RAVENNA, Livewire, Q-LAN and Dante. It also provides interoperability with layer 2 technologies, like Audio Video Bridging (AVB).
AF
Audio Frequency (see this).
AFM
Audio FM (see this).
Aging
See Surround Sound.
AIFF
Audio Interchange File Format (see this).
Ambience
Spatial effect, notably mixing of remotely placed microphones in order to include the atmosphere of the room on the recording.
For an alternating signal: the size of the variation.
Amplitude Modulation (AM)
Transfer of information by the variation of the amplitude of a carrier wave.
Analog
Quantities in two separate physical systems that have consistently similar relationships to each other are called analogous. One is then called the analog of the other.
Example: The sound pressure in front of a microphone and the electrical output of that microphone.
Analog to Digital Converter (ADC)
A circuit that converts an analog signal to a digital signal.
Anchor Element
The perceptual loudness reference point or element around which other elements are balanced in producing the final mix of the content. Alternatively, that which a reasonable viewer would focus on when setting the volume control.
A room in which all surfaces are absorbing the sound, thus providing reflection-free conditions. The anechoic room substitutes the outdoor free field. The reverberation time is as close as possible to zero seconds. The room is typically used for acoustical measurements of, for instance, microphone properties and psychoacoustic experiments.
American National Standards Institute is a federation of American organizations concerned with the development of standards.
Antenna Diversity
See Diversity.
Antenna Length
In wireless audio: The physical length of an antenna is strongly related to the wavelength of the radio wave. Most applied are half-wave or quarter-wave antennas.
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. The first version of this codec was developed by Queen’s University Belfast.
AR
Augmented Reality, see this.
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. Examples of arrays:
Endfire microphone: Microphone elements arranged in a straight line, all units time-aligned to the element furthest away from the sound source.
Sphere microphone: Microphone elements distributed on the surface of a rigid sphere. (Typical sizes: 10-25 cm diameter). The use of signal processing then obtains beamforming. The signal can be extracted into several audio channels providing multichannel options.
Unwanted effects that arise due to technical limitations.
ASCII
American Standard Code for Information Interchange. Character set encoding used in data transfer.
ASIO
Audio Stream Input/Output (see this).
ASK
Amplitude Shift Keying. In digital transmission, a method for modulating a digital signal onto an analog carrier.
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. The asynchronous sample rate converter can perform interpolation, and hence create the missing intermediate values so that glitches are avoided.
ATR
Audio Tape Recorder.
ATRAC
Adaptive Transform Acoustic Coding. Bit reduction system from Sony for use on MiniDisc. In stereo, 300 kbps is used. The system is also used for films. See SDDS.
ATSC
Advanced Television Systems Committee.
Attack
A dynamics descriptor. Transient response. Specifies whether the drumbeats and percussion, etc. are accurate and precise, i.e., if you can hear the actual strokes from the drumstick, the plucking of the strings, and such. It is also expressed as the ability to reproduce each audio source transient cleanly and separated from the rest of the sound image. Imprecise Attack is understood as having an unclear or muted impact.
Scale applied in listening tests: Imprecise - Precise.
[Reference: Report ITU-R BS.2399-0]
Attenuate
To reduce the level of an electrical or acoustical 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.
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. In this case, the soundtrack connects the two scenes.
Audio Engineering Society
A society for audio professionals.
Audio FM (AFM)
Designation for a video recorder's frequency-modulated sound track.
Audio Frequency
Audible frequencies, basically in the range of 20 Hz to 20.000 Hz. In connection with wireless systems.
Abbreviated AF.
Audio Interchange File Format (AIFF)
An uncompressed audio format developed by Apple.
Abbreviated AIFF.
Audio Stream Input/Output (ASIO)
ASIO is a PC sound card driver protocol for digital audio. It provides a low-latency and high-fidelity interface between a software application and a computer's sound card. Steinberg initially designed this standard.
Auditory Fatigue
A reduction in the sensitivity of the human auditory system caused by prolonged exposure to sound.
An additional layer on top of reality; the physical world mixed with virtual elements. The virtual elements can be presented to the user, for instance, by smartphones (with GPS), so different effects are site specific.
Autolocate
Facility on a tape unit's transport system.
Automatic Dialog Replacement (ADR)
Automatic replacement of location dialog with studio dialog. ADR can be carried out either for technical or creative reasons; it is sometimes used to change dialog during the editorial process.
Automatic Gain Control (AGC)
Method by which the amplification in a circuit is controlled by the input voltage or another parameter.
AUX
Auxiliary jack, an extra input or output.
AVB
Audio Video Bridging. An interface standard for the exchange of both sound and images, especially over shorter distances (usually max. 15 meters in cable).
AVI
A video-file in the Audio Video Interleave-format containing both video and audio. First developed by Microsoft in 1992.
Azimuth
Angle of a magnetic head gap in relation to the direction of travel of a magnetic tape.
Bb
Most popular terms
See all in B
See all in B
Microphone Dictionary
Bb
B-format (microphones)
A recording format virtually based on three orthogonally-oriented figure 8 microphones (X, Y, Z) and one omnidirectional microphone (W). By combining these signals a variety of directional characteristics can be obtained. Most B-format microphones are designed with cardioid microphones.
See Sound Field Microphone.
An expression related to the directivity pattern of antennas and microphones. The back lobe shows the sensitivity versus angle to signals coming from the back.
First-order microphones (except for omnidirectionals) have a main lobe (on-axis direction) and a back lobe. Higher-order microphones (and antennas) also have side lobes.
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. This would include content such as background music in film, wind noise, and more. Dialogue may be a background sound, for example when it consists of background voices in a public space, a restaurant, theatre, etc.
[Source: EBU Wiki - Technical - Louddrafting]
Baffle
1. A movable barrier used in the recording studio to achieve separation of signals from different sources (sometimes called “gobo”).
2. The surface or board on which a loudspeaker or a microphone is mounted.
3. A round disc with a diameter similar to the human head to be placed beween two microphones providing a sort of head related channel separation (The Jäcklin disc).
A spatial descriptor in audio assessment. Is the soundstage skewed to one side (left or right) or is it centered in the middle?
Scale applied in listening tests: Left - Center - Right.
[Reference: Report ITU-R BS.2399-0]
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. The balanced impedances to ground minimizes interference pickup.
When using balanced lines, the shield is not a part of the circuit. Induced electromagnetic noise is rejected due to the common mode, the fact that the impedance is exactly the same between each leader and ground. This is called common mode rejection.
The spacing between the frequencies at which a response attenuates by 3 dB.
Bass Depth
A timbre descriptor (bass range) in audio assessment.
Denotes how far the bass extends downwards. If it goes down in the low end of the spectrum, there is great depth. Should not be confused with Bass strength, which indicates the strength of the bass or Boomy which relates to resonances in the lower bass region.
Scale applied in listening tests: A little – A lot.
[Reference: Report ITU-R BS.2399-0]
Bass Management
A circuit that utilizes the subwoofer in a 5.1 (or higher) system to provide a bass extension for the five main speakers. The Bass Manager steers all frequencies below a selected frequency, such as 80 Hz, into the subwoofer along with the LFE (See LFE) source signal.
Bass Precision
A dynamics descriptor, a parameter for listening tests.
Are instrument impacts from the bass drum and bass precise, crisp and without distortion, are the impacts tight and well defined? Bass precision may be defined as Attack in the bass region. Imprecise means that the attack speeds in time and the peak of the impact is softened.
Scale applied in listening tests: Imprecise – Precise
[Reference: Report ITU-R BS.2399-0]
Bass Redirection
Another term for bass management, see this.
Bass Strength
A timbre descriptor (bass range) in audio assessment.
The relative level of bass, i.e., the low frequencies, for example male voices, bass guitar, bass drum, timpani and tuba. Should not be confused with bass depth that indicates the low frequency bass extension.
Scale applied in listening tests: Soft – Loud
[Reference: Report ITU-R BS.2399-0]
Batch
The number of sound or video media produced in the same fabrication process.
BCD
Binary Coded Decimal. Decimal digits converted to the base two system.
Beamforming
Generating specific directional characteristics based on the combination of signals for microphones in a microphone array (see this).
A compact wireless transmitter for lavalier microphones. Often attached to the belt but can also be attached other places.
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. It improves the quality of the recording with respect to both frequency response and distortion.
2: In assessment of audio: Making decisions based on irrelevant underlying preferences or predjudices.
Bidirectional Microphone
A microphone with a polar pattern like the figure-of-eight. One lobe is in-phase with the acoustic signal; the other lobe is out-of-phase. Also called a Gradient Microphone (see this).
Piezoelectric microphones are built on the principle of voltage generated by the flexing of piezo crystals. Typically, the piezo element consists of two quadratic crystal layers closely cemented in three corners. The fourth corner is affected by the moving diaphragm. This bimorph element provides a push-pull voltage output when sound moves the diaphragm.
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. For correct monitoring, the recording must be reproduced using headphones to eliminate crosstalk.
A form of modulation that, among other things, is used by the AES/ EBU interface and time code. In the bit stream, each bit shift is marked with a level shift (from high to low or vice versa). If the bit value is high, this is marked with a level shift in the middle of the bit concerned. Some of the advantages include the DC component in the signal is minimized and the signal is self-clocking.
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 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 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. Also called a Pop Filter.
Blimp
Due to its shape, a windshield for long microphones like shotguns is often called blimp or zeppelin. The term blimp (or barney) is also used for sound dampening cover/carpet to put over a noisy film camera.
BLM
See Boundary Layer Microphone.
Blumlein
Microphone configuration named after the inventor Alan Dower Blumlein (1903-1942). In this configuration, two coincident, bi-directional microphones are placed in an orthogonal arrangement of microphone axis.
BNC
The BNC connector is a bayonet-locking type for two-conductor coaxial cable, introduced in the late 1940'es. The name BNC is an abbreviation that has, over time, gotten several explanations; here are some of the more plausible: Baby N Connector (with reference to the bigger-sized N-connector used primarily for RF-connections), Bayonet N Connector, and Berkeley Nucleonics Corporation (the name of a primary equipment vendor).
Body Pack
See Belt Pack.
Boom
A long handheld pole for microphones, often used in film production. The operator is often called boom operator or boomer.
Boomy
A timbre descriptor (bass range) in audio assessment.
Resonances in the low bass, as if the sound was played in a large barrel, which gives a prominent bass resound (reverberating) when bass and bass drums are heard. The representation tends to become muddy and imprecise.
Scale applied in listening tests: None – Weak – Loud
[Reference: Report ITU-R BS.2399-0]
Bootleg
An illegally copied, unauthorized, and/or distributed version of a copyrighted film/video/music track. These are often of lower quality. Also termed pirated.
Bottleneck
1: A short metal tube (originally a glass bottleneck) used to touch the strings when playing the slide guitar or for use with ordinary guitar in folk music. Also called a slide.
2: A region in a singer's pitch range where a register change is mandatory. [Source: National Center for Voice and Speech]
Boundary Layer Microphones
Microphones placed directly on the surface of a large boundary (like a table- or wall surface). They are also called Pressure Zone Microphones or PZM microphones (PZM is a trademark of Crown). Due to the microphones position flush or close to the boundary layer, direct sound is gained by 6 dB and diffuse sound is gained by 3 dB.
A timbre descriptor (bass range) in audio assessment.
Boxy denotes a hollow sound, as if the sound was played inside a small box. Represents resonances in the upper bass frequency range.
Scale applied in listening tests: None – Weak – Loud
[Reference: Report ITU-R BS.2399-0]
Breathy Voice
The result of a widened glottis with excessive airflow that produces air turbulence. [Source: National Center for Voice and Speech].
Brilliance
A timbre descriptor (treble range) in audio equipment assessment: Treble or high frequency extension.
Scale applied in listening tests: A little: As if you hear music through a door, muffled, blurred or dull. A lot: Crystal-clear reproduction extended treble range with airy and open treble. Lightness, purity and clarity with space for instruments. Clarity in the upper frequencies without being sharp or shrill and without distortion.
[Reference: Report ITU-R BS.2399-0]
BS.1770
Formally ITU-R BS.1770. This specifies an algorithm that provides a numerical value indicative of the perceived loudness of the content that is measured. Loudness meters and measurement tools that have implemented the BS.1770 algorithm will report loudness in units of "LKFS".
A signal-related descriptor in audio assessment: Sound or noise with fast (<1 sec.) variations in frequency and/or loudness.
Scale applied in listening tests: A little – A lot.
[Reference: Report ITU-R BS.2399-0].
Buffer
Circuit for the maintenance or improvement of a function.
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.
Scale applied in listening tests: A little – A lot.
[Reference: Report ITU-R BS.2399-0].
Byte
Data word, consisting of a number of bits, normally 8.
Cc
Most popular terms
See all in C
See all in C
Microphone Dictionary
Cc
C
1: The symbol for capacitance (see this).
2: The abbreviation for Celsius (see this).
3: The abbreviation for coulomb (see this).
c/n
In wireless transmission: Carrier to Noise Ratio.
c/s
See Cycles per Second.
Calibration
The process of measuring to determine the accuracy of the measurement chain. A microphone calibration provides the absolute sensitivity of the unit.
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.
The music sounds like it is being played in a can or tube. The sound is characterized by prominent and narrowband resonances in the midrange.
Scale applied in listening tests: A little – A lot
[Reference: Report ITU-R BS.2399-0]
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. It consists of two plates of conducting material. The conducting materials are sandwiched around an insulator made of, for instance, ceramic, film, glass, or air. (Hence the names ceramic condenser, film condenser, etc.). The insulator is also known as a dielectric, and it boosts a capacitor’s charging capacity.
In condenser microphones, the dielectric is air. One of the backplates and the diaphragm form the capacitor.
Capacitors and batteries both store energy. While batteries release energy gradually, capacitors discharge it quickly.
Capacitor Microphone
See Condenser Microphone.
Carbon Microphone
A microphone element that consists of two metal plates separated by granules of carbon. When one plate (the diaphragm) is vibrating, the carbon's resistance varies, modulating an electric current through the element. Earlier, widely used for telephones.
Cardioid Microphone
A microphone with a unidirectional characteristic that picks up sound in the front.
A waveform (typically a sine wave) whose frequency or amplitude is modulated by a signal. Like, for example, in wireless transmission (radio or wireless mics).
Cartridge
Special tape cassette with 1/4-inch tape earlier used for jingles, ads, etc., at radio stations. Format: mono, stereo or 8-track versions.
Cat #
Category of cables for Ethernet. The number describes quality. Higher numbers means higher quality:
Cat 5 enables bandwidth of 100 MHz.
Cat 5E (Enhanced Cat 5) enables bandwidth of 350 MHz.
Cat 6 enables bandwidth of 550-700 MHz. Cable run 50 m.
Cat 6A (Augmented Cat6) as Cat6, however cable run up to 100 m.
Cat 7 enables bandwidth of ≥700 MHz.
Cat 7A (augmented Cat7).
CC
See Compact Cassette.
CCIR
Comité Consultatif International pour la Radio (Consultative Committee on International Radio). Formed in 1927 to manage the international radio frequency spectrum and to develop standards for radio broadcast systems, primarily in Europe. In 1932, the CCIR merged with the International Telegraph Union (ITU) and several other organizations to become the International Telecommunication Union in 1934. In 1992, the CCIR became the ITU-R, the radio communications section of the ITU.
The CCIR Curve is a standardized weighting curve for the measurement of noise, for instance, in microphones. The standard was originally numbered in the CCIR system as CCIR 469-4 but is now maintained by the ITU and named ITU-R BS.468-4.
A unit for temperature. The behavior of water defines the scale: 0 °C: Point of water freezing; 100 °C: Point of water boiling. The scale is named after the Swedish scientist Anders Celsius.
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.
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. The number of available channels varies from brand to brand: from 12 channels to 63 channels within one 8MHz frequency channel. Packing more channels is usually at the cost of other qualities.
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. External voltage is applied to traditional condenser microphones. Electret microphones are pre-charged and will only need external supply for the built-in electronics.
Chest Voice
A term used within vocal music, especially in classical singing. However, the use of this term varies widely within vocal pedagogical circles and there is currently no one consistent opinion among vocal music professionals in regard to this term. It is not acoustically measurable. The term can be used in relation to the following:
• A particular part of the vocal range or type of vocal register
• A vocal resonance area
• A specific vocal timbre
[Source: Wikipedia].
Clapboard
A small board that displays information for each shot in a movie or documentary and is filmed at the beginning of a take. The board typically contains the working title, the names of the director, editor and director of photography, the scene and take numbers and the date and time.
On the top of the clapboard is a hinged wooden stick (called a clapstick or clapper) which is often clapped to provide audio/visual synchronization of the sound with the picture during editing. Electronic clappers and synchronization are also used instead of the old-fashioned clapboard. Also called Clapper. [Source: Filmsite.org]
Clarity
A transparency descriptor in audio assessment.
The impression of how clearly different elements in a scene can be spatially distinguished from each other.
A singer and a piano performing a duet in a dry acoustic, may be perceived as clear. When listening to a choir from the rear of the church, the sound of the individual singers may be unclear.
Scale applied in listening tests: Unclear - Clear
[Reference: Report ITU-R BS.2399-0]
Clean
A transparency descriptor in audio assessment.
It is easy to listen to music, which is timbral clear and distinct. Instruments and vocals are reproduced accurately and distinctly. The opposite of clean: dull, muddy.
Scale applied in listening tests: A little – A lot
[Reference: Report ITU-R BS.2399-0]
Clean Sound
Atmospheric sound.
Clipped
A signal-related descriptor in audio assessment.
The harmonics are too pronounced and sharp.
Scale applied in listening tests: A little – A lot
[Reference: Report ITU-R BS.2399-0]
Clipping
An electrical signal is clipped if the signal level exceeds the capabilities of the amplifier. It is a distortion of the signal.
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. The result is a series of tops and dips across the frequency response that makes it look like a comb.
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). This is called common mode rejection.
Compact Cassette, CC
Registered name for the cassette developed by Philips with a 3.81 mm (0.15 in) audio tape.
Compander
A contraction of compressor and expander. A device that can perform both functions.
Complex tone
A tone that consists of more than a single frequency. See also Harmonic Overtones.
Component Frequency
Another term for harmonic or partial. Basically, a pure tone (perceptually) or sinusoid (mathematically).
Compressed
A signal-related descriptor in audio assessment.
Limited dynamic range leading to a lack of natural peaks. Dynamic compression may be heard as a pumping effect.
Scale applied in listening tests: A little – A lot
[Reference: Report ITU-R BS.2399-0].
Compression
Reduction of the dynamic range of recorded audio.
Compressor
A device or a plug-in that provides reduction of the dynamic range of recorded audio.
Condenser Microphone
A microphone in which the diaphragm is one plate of a capacitor. The capacitance of the microphone condenser is typically in the range of 10 – 50 pF.
The ability of a material to conduct electricity. It is the reciprocal of resistance and thus calculated as the current divided by the voltage (G=1/R=I/U). The unit in the SI system is Siemens. Formerly the unit Mho [Ʊ] applied (ohm spelled backward).
Consonant
1. In phonetics, a speech sound that is articulated with a complete or partial closure of the vocal tract (contrary to vowels). Examples are B, P, G, K, T. In non-tonal languages, consonants are essential for speech intelligibility.
2. In music, generally, consonant means pleasing tonality, having good harmony.
3. The name of a rock band.
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.
Content 0
Material or essence used for distribution by an operator.
Convolution Reverb
Convolution reverb is a software-based process used for digitally simulating the reverberation of a physical or virtual space. It is based on the mathematical convolution operation and uses a pre-recorded audio sample of the impulse response of the space being modeled. The impulse response is typically a recorded pistol shot, balloon popping or the like. Each recording describes the response in that specific position. The impulse response is then convolved with the incoming audio signal to be processed.
Core Audio
Core Audio is a driver protocol for digital audio in Apple's Mac OS X and IOS operating systems. It provides a low-latency and high-fidelity interface between a software application and sound card.
Corner Frequency
Transition frequency of a filter.
Corner Vowels
Vowels [a], [i], and [u]; vowels at the corner of the vowel triangle; they necessitate extreme placement of the tongue. [Source: National Center for Voice and Speech].
Coulomb
A unit of electric charge, equal to the quantity of electricity (electrons) transferred in one second by a current of one ampere. It takes approximately 6.24 * 1018 electrons to establish one coulomb of charge.
The condenser microphone is either internally charged (electret condenser microphone) or externally charged.
CPS
Cycles per Second (see this).
CRC
Cyclic Redundancy Check. Error correction.
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.
[Source: National Center of Voice and Speech].
Crest Factor
The term used to represent the ratio of the peak (crest) value to the RMS value of a waveform. For example, a sine wave has a crest factor of 1.4 (or 3 dB), since the peak value equals 1.414 times the RMS value. Music has a wide crest factor range of 4-10 (or 12-20 dB). This means that music peaks can be 12-20 dB higher than the RMS value, which is why headroom is so important in recording and audio design.
Critical Band
In human hearing, only those frequency components within a narrow band, called the critical band, will mask a given tone. Critical bandwidth varies with frequency but is usually between 1/6 and 1/3 octave. The ears act like a set of parallel filters, each with its own bandwidth.
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.
The process of gradually fading from one audio source to another. In the middle, both sources can be heard.
Crossover Frequency
In a loudspeaker with multiple radiators, the crossover frequency is the -3 dB point of the network dividing the signal energy.
Crosstalk
In audio equipment, crosstalk is any phenomenon by which a signal transmitted in one channel creates a audible/measurable portion in other channels.
Crystal Microphone
Crystals which exhibit the piezoelectric effect (see this) create voltages when they are deformed. A crystal microphone uses a thin strip of piezoelectric material attached to a diaphragm. The two sides of the crystal acquire opposite charges when the crystal is deflected by the movement of the diaphragm.
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. This grip causes coloration of the frequency response. Applies in particular to beatboxers.
Term used in CVT (Complete Vocal Technique): Curbing is the half-metallic mode, meaning there is some metal in the notes. It is the 'mildest' of the metallic modes where the character is softer and not as powerful and distinct as Overdrive or Edge but still powerful compared to Neutral. The sound is often slightly plaintive and restrained.
Cutoff
The cutoff frequency of a filter. The frequency at which a filter begins to attenuate. Often defined by the attenuation being 3 dB at the frequency concerned.
CVT
Complete Vocal Technique. A singing technique developed by Cathrine Sadolin.
Cycles per Second (CPS or C/S)
Formerly used for the quantification of frequency, Hz.
A plug type that can be used, among other things, for the transfer of digital signals. The flange around the connector pins are D-shaped, hence the name.
DAC
See Digital-to-Analog Converter.
Damped waves
A wave in which the amplitude decreases over time (contrary to continuous wave). Example: The sound of a drum or a bell.
Damping
Removal of echoes and reverberation using sound absorbing materials.
Damping material
A material that absorbs, reduces or disperses sound waves to control reverberation.
See also: Absorber
Digital Audio Network Through Ethernet / AoE / AoIP. Initially developed by Audinate. Many third-party manufacturers support the protocol.
Dark - Bright
A timbral balance descriptor in audio assessment.
Denotes the balance between bass and treble.
Scale applied in listening tests:
• Dark: Excessive bass. Either loud bass or weak treble
• Neutral: Bass and treble are perceived equally loud, there is a balance in the reproduction. This also applies if both bass and treble are equally weak or if the bass and treble are both too loud. If it leads to prominent or soft midrange this is assessed by the Midrange strength
• Bright: Excessive treble. Either loud treble or weak bass
The cause for the sound being dark or light can be deduced from the assessments of Bass Strength and Treble Strength.
[Reference: Report ITU-R BS.2399-0]
DAT
Digital Audio Tape (-recorder). Digital tape format (cassette). Normally understood as R-DAT (Rotary head DAT) as opposed to S-DAT (Stationary head DAT), which never became a widespread format.
An acoustic measurement where an A-weighting band-pass filter is inserted in the measurement chain. The A-curve is specified by the IEC. It reduces frequencies below 1 kHz but slightly gains frequencies in the range of 1-4 kHz. This curve emulates the ear’s frequency sensitivity at low levels.
dB(C) or dBC
An acoustic measurement where a C-weighting band-pass filter is inserted in the measurement chain. The C-weighting curve is specified by the IEC. The corner frequencies (-3dB) are 31.5 Hz and 8 kHz respectively.
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. It usually refers to a reference level such as -20 dBFS or -14 dBFS. It is applied to indicate that the signal may contain values exceeding 0 dBFS.
dBTP
Decibels, true-peak relative to full scale (per ITU-R BS.1770 Annex 2).
dBu
Logarithmic ratio with a reference of 0.775 V.
dBV
Logarithmic ratio with a reference of 1 V.
DC
Direct Current (see this).
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. This is an unwanted phenomenon in audio; however, DC offset often occurs in inferior sound cards.
De-clipping
An algorithm designed to reconstruct audio signals which exhibit clipped waveforms. The reconstruction works best for digitally-clipped signals (signals exceeding 0 dBFS). The result is seldom beneficial if applying any filtering before the de-clipping process, as this may change the waveform.
De-emphasis
See Emphasis.
De-esser
Signal processing to reduce excess sibilance, typically in vocal recordings.
Decade
Ten times any quantity or frequency range. The frequency range of the human ear is about three decades.
Decay Rate
A measure of the decay of acoustical signals, expressed as a slope in dB/second. The rate at which a signal drops off.
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. Originally, it used three cardioid microphones, but later switched to omnidirectional microphones (Neumann M50s). The mics are arranged in an upside-down “T” pattern. Two microphones are placed left and right approximately 2 m (6 ft) apart with the third placed in the center about 1 m (3 ft) in front, approximately 2.5-3 m (8-10 ft) up. This configuration produces a strong stereo image. It is sometimes called ABC Stereo.
[Source: Los Senderos Studio, Recording Studio Glossary]
Suitable restructuring of data, for example swapping bandwidth (sampling frequency) for bit depth.
DECT
Digital Enhanced Cordless Telecommunications. Originally for domestic cordless telephones. The allocated frequency band around 1.9 GHz is now available for license-free wireless microphone systems.
Delay
Time delay. (1) Electrical circuit that can delay a signal, in practice from fractions of a millisecond up to multiple seconds; used for sound effects. (2) Unwanted effect of time-consuming digital conversion, processing, etc.
See Latency.
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. After this process, this bit stream is converted to standard values, for example 16-bit format.
Depth
A spatial descriptor in audio assessment.
The radial extent of source, scene or ensemble from the listener (in any direction away from the listener).
A talker in a dry acoustic environment may be perceived as having little or no depth. A crowd in a stadium has depth. The sounds of the crowd are simultaneously occurring close to and far from the listener.
Scale applied in listening tests: Shallow - Deep.
[Reference: Report ITU-R BS.2399-0]
Detailed
A transparency descriptor in audio assessment.
A well-resolved sound, rich in detail. Instruments, voices etc. can easily be separated.
Music has many details, details that cannot be measured, details that give the music "soul". It may be small audible nuances: Breathing from a singer, fingers wandering across the guitar strings, the flaps from the clarinet, embouchure sound of the saxophone, the impact from the piano's hammers when they hit the strings, to name a few.
Scale applied in listening tests: A little – A lot
[Reference: Report ITU-R BS.2399-0]
DHCP
Dynamic Host Configuration Protocol, see this.
DI
1. Digital In, digital input.
2.Direct Injection, intermediate amplifier.
3.Directivity Index, directional index for acoustic transducers.
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).
2: In multi-channels systems, the dialog level adjust is a level-setting of the center-channel, which usually carries the dialog.
In film, dialogue matching is a process to make secondary recordings of dialog (from lavaliers, plant mics, a dubbing studio, etc.) sound the same as the primary recordings (from overhead boom mic or the like). Izotope has introduced Dialog Matching as a plug-in for ProTools.
Diaphragm
The movable part in a microphone that reacts to the sound. Often also called the membrane.
Difference Frequency Distortion
Difference frequency distortion considers only the difference terms of intermodulation distortion. Such tones are not harmonically related and are therefore musically undesirable. It is a percentage of the signal amplitude.
Diffraction
The distortion of a wave front caused by the presence of an obstacle in the sound field. The scattering of radiation at an object smaller than one wavelength and the subsequent interference of the scattered wavefronts.
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.
Concerning a state wherein an electrical signal has been converted to a series of impulses according to a specific code. The signal has come to exist in "tabular form".
The DAW was initially a dedicated computer-based system for recording, editing, and mixing audio. Today DAWs are software-based systems to be used with most standard IOS or Windows-controlled computers.
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.
An electric charge driving the current – the electrons – in only one direction (contrary to Alternating Current, AC, which drives the current in both directions).
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. In sound for film, the technique of recording sound simultaneously with the recording of the image.
Measure of the response of a microphone to sound incident from various angles or of the radiation pattern of a loudspeaker. The sensitivity (referred to as on-axis sensitivity) is plotted as a function of angle of incidence at various frequencies.
Also called "polar pattern".
The ratio of the mean-square pressure (or intensity) on the axis of a transducer at a certain distance to the mean-square pressure (or intensity) that a spherical source radiating the same power would produce at that point.
Directivity Index (DI)
Directivity factor expressed in dB (10*log(directivity factor)).
Mixing (of images). Corresponds to crossfade in audio.
Distance
A localization descriptor in audio assessment.
How far a sound source, ensemble or scene is perceived from the listener. Hearing a person talking close to a listener in a park may be perceived as near, whereas a person at a large distance may be perceived as far.
Scale applied in listening tests: Near – Far
[Reference: Report ITU-R BS.2399-0]
Distance Double Law
When you double the distance from a point source, the sound pressure is halved (reduced by 6 dB).
Distorted
A signal-related descriptor in audio assessment.
Additional and undesired sounds that add a sharpness to the reproduction.
Scale applied in listening tests: A little – A lot
[Reference: Report ITU-R BS.2399-0]
Distortion
Any change in the waveform or harmonic content of an original signal as it passes through a device. The result of non-linearity within the device.
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. The purpose is to reduce distortion at low levels. To further reduce audibility of the added noise commonly noise shaping is used.
Diversity
True Diversity or Receiver Switching: In wireless microphone transmission, the principle that one receiver contains two separate antennas and two separate receiver circuits. The signal from the receiver with the strongest reception is passed to the output.
Antenna Diversity or Antenna Switching: The receiver contains two antennas from which the strongest signal is passed to the receiver via a fixed interval switcher.
DivX
A brand name, usually referring to the DivX codec, which by applying MPEG-4 algorithms, provides compression of long videos to reduce their file sizes while keeping the video quality relatively high.
DO
Digital Out; digital output.
Do di petto
(Italian term in singing) C in chest.
Dolby E
An audio data-rate reduction technology designed for use in contribution and distribution that also conveys Dolby E metadata.
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.g. ambulance passing a bystander).
To automatically extract a stereo or mono mix from a higher-order immersive format system like 5.1, 7.1.4, or Dolby Atmos.
DPSK
See PSK.
DRC
Dynamic range control.
DRC Profile
A collection of parameters that describe how dynamic range control metadata is calculated.
Drop Frame
Variant of time code, where a frame is periodically skipped in order to preserve synchronization.
Drop-out
Short-duration loss of the signal on a tape due to faults in the tape's magnetic coating.
Dry Miking
See Close-miking.
DSB
Digital satellite broadcasting.
DSP
Digital signal processor. A circuit that can perform manipulation of data.
DTS
Digital Theater System. Digital sound system originally for movies. The sound information is stored on a CD-ROM, which is controlled by a time code on the film. Uses APT-X bit reduction.
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. This is where the final decisions are executed regarding the sonic elements of the film. A dubbing stage gives the decision-makers the best possible representation of how all the audio and visual elements are working together in the context of how the film will be seen and heard. Often the dubbing stage is used for re-recording location dialogue. [Source: Filmsite.org]
Ducking
Automatic compression, for example when a speaker's insert dims the music signal.
Durability Factors
Important set of features for microphones. Includes how well the microphone withstands heat, cold, mechanical stress, dust, humidity, sweat, electromagnetic fields, etc.
A DHCP-server in the network provides the connected units with the network information they need to work.
Dynamic Microphone
A microphone with an electrodynamic transducer; either moving coil or ribbon microphone.
Dynamic Range
Range between the quietest and loudest levels a device can produce or detect. For a microphone or measuring system, it is normally specified as the range between the inherent noise level and a level leading to a specified amount of distortion.
A word created as an audio parallel to the visually based icon/iconography. An “earcon” is an easily recognizable sound used for messaging, i.e., in computers, smartphones. or household devices (I.e., the “ding” when the microwave has finished your popcorn or the “litter sound” when your computer’s waste bin empties.)
Early Decay Time (EDT)
In room acoustics, the first 10 dB of the decay after the sound has stopped.
A microphone setup developed by Eberhard Sengpiel of the Berlin University of the Arts. This setup is based on two cardioid microphones spaced 25 cm (9.8 inches) apart and at an angle of 90°. Similar techniques use other angle values, but 90° is considered easier to set up. The EBS technique can be categorized as a near-coincident design.
[Source: Los Senderos Studio, Recording Studio Glossary]
Eight-to-fourteen modulation. Digital modulation form, used for CDs among other things.
EFP
Electronic Field Production. The production form typically applied for drama and documentary produced outside the studio.
EFX
See Special Effects.
EIAJ
Electronic Industry Association of Japan. An interest organization in Japan that issues some norms.
Eigen Mike
An array microphone that Meyer and Agnello developed in 2003. It consists of 32 miniature microphones arranged on an 84 mm diameter rigid sphere. By processing the microphone signals, higher-order ambisonic directivity patterns can be obtained (up to 4th order).
Eigentone
(From German). 1. A tone that emanates from the resonance of a vibrating body or an acoustic space.
2. In film sound: Characteristic noise of a specific room. Sometimes called room tone.
Electret Microphone
A condenser microphone with a permanently charged membrane/back electrode. External voltage only needed for impedance conversion/built-in electronics.
An electronic or electrical product like a microphone must work as intended in its environment. The microphone should not generate electromagnetic disturbances, which may influence other products. Moreover, it should exhibit immunity to other equipment and systems' electromagnetic fields. Electromagnetic interference (EMI) should not occur.
A technique often used in analog transmission systems (wireless microphones, FM broadcast, etc.) or analog recording media (vinyl, tape, etc.) to enhance dynamic range by raising predominantly higher frequencies. De-emphasis is introduced on the receiving side.
The process of converting information (signal) into a coded form.
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. Also called "pencil microphone".
ENG
Electronic News Gathering. TV production of news based on electronic video camera as opposed to film camera.
Envelopment
A spatial descriptor in audio assessment.
Degree of being surrounded by a source, scene or ensemble. Typically, envelopment is associated with a scene.
Being surrounded by reverberation would be considered highly enveloping. Being surrounded by a large number of dry sources may also be highly enveloping. This may be heard when standing and listening to the rain hitting the pavement. Envelopment may occur with reverberation or other aspects of the scene such as applause in a concert hall, atmosphere or air conditioning (room tone). Holes (an absence of sound from a certain directions) in the reproduction would normally reduce envelopment.
Envelopment may be subdivided into horizontal and vertical envelopment.
Scale applied in listening tests: Scale: Not enveloping – Completely enveloping.
Epiglottis
A flap of cartilage that seals the entry-way to the larynx during swallowing and opens the entry-way during breathing
[Source: National Center of Voice and Speech].
Equal Loudness Contour
A contour representing a constant loudness for all audible frequencies. The contour with a sound pressure level of 40 dB at 1000 Hz is arbitrarily defined as the 40-phon contour.
Equalizer, Graphic
Electronic equipment for "equalizing." Built from a number of 1/1 octave or 1/3 octave band-pass filters that can each amplify or attenuate and used to obtain a desired frequency response.
Equalizer, Parametric
Electronic equipment for "equalizing". Constructed from a set of filters where the center frequency, bandwidth and amplification/attenuation can be adjusted independently for each filter.
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.
2. Equalization of nonlinearity (in frequency response).
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.
A computer network technology used in Local Area Network (LAN), Metropolitan Area Network (MAN), and Wide Area Network (WAN). Coax cables, twisted pairs, and fiber optics are applied. The bitrate is currently up to 400 Gbps (Gigabits per second).
ETSI
European Telecommunications Standards Institute. Publishes standards for wireless transmission, of which 300-422 is one: Allows a maximum RF channel bandwidth of 200 kHz.
Expander
1. Electronic equipment in which the output signal's dynamic range is increased in relation to that of the input signal.
2. Designation for a controllable synthesizer without a keyboard.
Ff
Most popular terms
See all in F
See all in F
Microphone Dictionary
Ff
F
Farad, see this.
F/X
See Special Effects.
F0
(F zero) Fundamental frequency of a tone containing multiple harmonics. Mainly used within voice research.
Fade
A gradual change in the intensity of a sound. Fade in turns up the level. Fade out reduces the level to silence. Crossfade is the process of gradually fading from one audio source to another. Halfway through the crossfade, both sources can be heard.
Far End Audio
A term usually applied to networked audio. Network to loudspeakers.
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 of distance from the source).
Farad is the SI-derived unit of electrical capacitance; the ability of a body to store an electrical charge. The unit is named after the English physicist Faraday.
FFT
Fast Fourier Transform. An efficient method of estimating the frequency spectrum of a signal.
File-based Scaling Device
A device used to apply an overall gain correction to audio content stored as files.
Filter
A device or algorithm for separating components of a signal based on its frequency. It allows components in one or more frequency bands to pass relatively unattenuated while attenuating components in other frequency bands.
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. They are used in instrumentation to eliminate low-frequency noise and to separate alternating components from direct (DC) components in a signal.
Filter, Low-cut
A filter that cuts off low-frequency signals below the cutoff frequency with a certain attenuation (roll off). In microphones, the filters are typically active below 80-300 Hz, and the slope is typically 6 or 12 dB/octave.
See also Filter, High-pass.
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. Used to remove individual frequencies, for example hum.
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. The capacity is around 3.2 Gbps; competing standards: Thunderbolt and USB.
First-Order Pattern
See 1st Order Pattern.
Flanging
Sound effect based upon the direct signal mixed together with itself using varying time delays. Originally made using a tape recorder, where the source reel is slowed down by a finger placed on the flange of the reel.
Fluctuating / Intermittent
A signal-related descriptor in audio assessment.
Noise with varying loudness and/or pauses.
Scale applied in listening tests: A little – A lot.
[Reference: Report ITU-R BS.2399-0].
FM
Frequency modulation. Modulation principle in which a carrier wave is varied about its center frequency in proportion to the frequency of the modulating wave and where the oscillation of the carrier wave is proportional to the amplitude of the modulating wave.
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. They are given a fold back or monitor loudspeaker, where the sound is specially mixed for this purpose.
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.g., footsteps, gunshots, kisses, fight-sounds, punches, storm noises, slamming doors, explosions, etc.) that are synchronized to the film to match its visual component. [Source: Filmsite.org]
Foreground Sounds
Sounds that are required or appreciation of the program. Typically presented through the front channels of a surround presentation, usually consisting of sounds made by objects or people shown in an accompanying picture. Dialogue can usually, but not always, be classified as foreground sound. Music is a foreground sound in music television, or music radio programs.
[Source: EBU Wiki - Technical - Louddrafting]
Formant
Voice: A resonance in the vocal tract. A given voice sound may contain several formats independent of the spoken vowels, named F1, F2, F3, etc.
Musical instrument: A resonance in the instrument. It gives the instrument its characteristic sound almost independent of the tone played.
Formant Bandwidth
The difference in frequency between the two half-power points (i.e., -3 dB with reference to the top point) on the slopes of the formant frequency.
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.
[Source: National Center of Voice and Speech].
Forwarding and Queuing for Time-Sensitive Streams (FQTSS)
A term that applies to the AVB (Audio Video Bridging) interface standard.
FQTSS
Abbreviation for Forwarding and Queuing for Time-Sensitive Streams. See this.
Frame
In video, an image. The smallest unit of a time code.
Frame Sync
Short for "frame synchronizer".
Free Field
An environment in which there are no reflective surfaces within the frequency region of interest and the sound is isotropic and homogenous.
The ratio of the output open-circuit voltage of a microphone to the free-field sound pressure in an undisturbed plane progressive wave. Frequency and angle of incidence must be specified.
Frequency
The number of cycles per second, measured in Hertz (Hz) or 1000 Hz=kHz. The human ear is able to detect frequencies from appr. 20 Hz to 20 kHz. In terms of musical practice, the frequency correspond to pitch. This table shows the fundamental frequency of each key on a grand piano.
Frequency Band
A limited frequency range.
AF (Audio Frequency): Typical bands applied in the audible frequency range are octaves or fractions of octaves. Some frequency bands are standardized by ISO and named after the center-frequency: The 1 kHz octave band includes the frequency range 707 Hz to 1.414 kHz.
RF: Radiowaves (3 kHz – 300 GHz) are divided into frequency ranges, bands, i.e., Long Wave (LW), Medium Wave (MW), Short Wave (SW), Very High Frequency (VHF), Ultra High-Frequency UHF), etc. Within each band, a number of channels can be defined as the television channels in the UHF range.
Frequency Range
The frequency range is also called the microphone "bandwidth".
Unlike the frequency response it is not represented by a graph but will give the sound engineer a rough indication of the microphone's tonal span and weather it will match the full span of the sound source.
The frequency range states the microphone's upper and lower limiting frequencies plus the tolerance field of the on-axis response in dB. If no tolerance field is indicated the frequency range is submitted as the -3dB points of the on-axis response.
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. The frequency response gives important information about the tonal balance of the microphone under different acoustic conditions.
In digital (radio) transmission, a method for modulating a digital signal onto an analog carrier. For example, 4FSK modulates four frequencies on a carrier wave.
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.
A fricative is a consonant sound that is made when you squeeze air through a small hole or gap in your mouth. When these gaps are used, the fricatives are called sibilants.
See Sibilance
Speech sounds produced by turbulence in a constriction of the vocal tract, such as an "s" produced with the teeth.
[Source: National Center of Voice and Speech].
FSK
Frequency Shift Keying (see this).
Fukada Tree
The Fukada Tree is designed by the Japanese audio engineer Akira Fukada in 1997. It is a microphone array based on the Decca Tree, but with five cardioid microphones and two additional omnidirectional microphones as outriggers to blend in between the front and rear channels.
Full
A timbral balance descriptor in audio assessment.
If both low and high frequencies are well represented with good extension the sound is Full.
Scale applied in listening tests: A little – A lot
[Reference: Report ITU-R BS.2399-0]
Fundamental Frequency
The lowest frequency of a vibrating system. The spectrum of a periodic signal will consist of a fundamental component at the reciprocal of the period and possibly a series of harmonics of this frequency.
Gg
Most popular terms
See all in G
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Microphone Dictionary
Gg
G
1: Large room acoustics: G is the sound strength (or relative sound level). G is measured using a calibrated omnidirectional sound source and is the ratio in dB of the sound energy of the measured impulse response to that of the response measured at a distance of 10 m from the same sound source in a free field.
2: Abbreviation for the SI prefix giga (10^9). See this.
Gaffer
In film production: The chief or head electrician or supervisory lighting technician in the film/photography crew on a movie set. The gaffer is responsible for the design and execution of a production's lighting plan on the set. The gaffer's right-hand assistant is known as the best boy. Gaffer tape refers to multi-purpose, sticky and wide black or gray cloth tape, used to mark studio floors, to hold things together, etc. Gaffer tape is also known as duct tape. [Source: Filmsite.org]
Gain
Amplification (in a circuit).
Gain Structure
The signal levels at different stages of a mixing console or a chain of audio devices. I.e. microphone level, line level, instrument level.
Gate
See Noise Gate.
Gear
Encompasses all equipment.
Giga (G)
SI prefix giga (10^9) like in Ω (gigaohms). Or in data storage giga (2^30): 1 GB = 1,073,741,824 B. (See Numbers in audio).
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.
[Source: National Center of Voice and Speech].
Glottis
The airspace between the vocal folds.
[Source: National Center of Voice and Speech].
Gobo
See Baffle.
Gooseneck
A flexible boom for microphones. Length: From few cm/inches to 1 m (3 ft)
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. All 1st order directional microphones have some gradient component. A pressure microphone (zero order) does not have a gradient component. See 1st Order Pattern.
Figure 1 Left microphone is a gradient type (inlet to both the front and rear of the diaphragm), and the right microphone is a pressure type (only admittance from one side of the diaphragm).
Granular Synthesis
A technique of assembling (small) segments of recorded sounds – called grains – into new sounds. In the process, parameters like the grains' duration, the starting point in the file, pitch, modulation, and spatial distribution can be controlled. Granular synthesizers are either dedicated hardware devices or plug-ins for other systems.
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 conductive rod driven into the ground).
In wiring for audio, a screen around circuitry or wires connected to the ground shields from electrical/electromagnetic noise.
In electricity supply (mains installations), the ground wire provides an alternating route for current to flow back to the ground if there is a fault in the wiring system.
Groundplane Antenna
A antenna with one director, vertical quarter-wave element, and three reflectors at 120°.
Group delay
Digital processing takes time. Group delay is the delay over the complete frequency range observed and should stay constant at all frequencies. If the frequencies are delayed differently, it is called phase delay.
Hh
Most popular terms
See all in H
See all in H
Microphone Dictionary
Hh
Haas Effect
Also called the precedence effect or principle of first arrival. If similar sounds arrive at the ear within approximately 35 ms, the sound's apparent direction is that of the direct sound. The auditory apparatus integrates delayed sounds if they fall on the ear within 20-40 ms of the direct sound. The level of the delayed components contributes to the apparent level of the sound and may be accompanied by a change in the character (timbre) of the sound.
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. The Hamasaki Square is designed for capturing the ambient/diffuse part of a surround sound recording. It is a four-mic square with 1.8-2 m (5.9-6.6 ft.) between the figure-of-eight microphones, which are routed to left, right, left surround, and right surround at an appropriate level compared to the front array. The figure-of-eight microphones are pointed with their in-phase sensitive directions against the sides and with their nulls to the direct sound.
Compared to other systems for ambiance recording, this system is the least sensitive regarding the distance between the main array and the ambiance array.
Handling Noise
The sensitivity of a microphone to movement and shock. Expressed as an equivalent sound pressure level.
Harmonic
A discrete sinusoidal (pure-tone) component whose frequency is an integer multiple of the fundamental frequency of the wave. If a component has a frequency twice that of the fundamental, it is called the second harmonic, etc.
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. An interface standard for audio and pictures exchange over shorter distances (usually max 15 m/45-foot cable). Two connectors are dedicated to physical connections within the format.
Head Related Stereo
Stereo techniques using human interaural geometry as a model for the microphone set-up. Head related stereo is a generic term for a lot of different stereo techniques using both difference-in-time and difference-in-intensity stereo with microphone spacing and microphone off-axis attenuation related to the distance between the human ears and the shadow effect of the human head. Among the more standardized head related stereo techniques are ORTF stereo and DIN stereo.
A term used within vocal music, especially in classical singing. However, the use of this term varies widely within vocal pedagogical circles and there is currently no one consistent opinion among vocal music professionals in regard to this term. It is not acoustically measurable. The term can be used in relation to the following:
• A particular part of the vocal range or type of vocal register
• A vocal resonance area
• A specific vocal timbre
[Source: Wikipedia].
Headroom
Overload reserve. The amount of signal above nominal level that can be permitted before overloading arises with distortion as a consequence.
Hearing Level
A measured threshold of hearing at a specified frequency expressed in decibels relative to a specified standard of normal hearing. The deviation in decibels of an individual’s threshold from the zero reference of an audiometer.
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.
The format consists of a top layer triangle of three cardioid microphones spaced 35 cm and angled 120° relative to each other. In addition, a bottom layer spaced 35 cm below the top layer, consists of three cardioid microphones also arranged in a triangle like the upper layer. However, the bottom layer is rotated by 60° relative to the top layer. For the reproduction, each channel feeds one loudspeaker arranged in a similar configuration as the microphones.
HF
High frequency.
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.They are used in instrumentation to eliminate low-frequency noise and to separate alternating components from direct (DC) components in a signal.
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 (See A-format, B-format and Soundfield Microphone).
Higher order means that the microphones involved are of an order different from 0 or 1st order microphones (see 1st Order Pattern.
A signal-related descriptor in audio assessment.
A noise-like sizzling sound, like the sound of bacon in a frying pan.
Scale applied in listening tests: A little – A lot.
[Reference: Report ITU-R BS.2399-0].
HOA
Higher Order Ambisonics (see this).
Homogeneous
A timbral balance descriptor in audio assessment.
Denotes to which degree the different frequency ranges (bass, midrange and treble) are coherent, continuous and balanced without gaps between them. That there are seamless transitions between the tone ranges.
Scale applied in listening tests: A little – A lot
[Reference: Report ITU-R BS.2399-0]
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. The principle is to add a coil in series with the microphone's moving coil. This additional coil is oriented like the voice coil but mounted outside the magnetic system and reversely wound. This provides cancellation of external stray fields from powerlines, induction loops, etc.
Humming
A signal-related descriptor in audio assessment.
Low-frequency noise with tonal components.
Scale applied in listening tests: A little – A lot.
[Reference: Report ITU-R BS.2399-0].
HVAC noise
Heating, ventilation and air conditioning noise. Used in connection with requirements concerning noise in control rooms, cinemas, etc.
Another expression for wide cardioid (or subcardioid).
Hz
See Hertz.
Ii
Most popular terms
See all in I
See all in I
Microphone Dictionary
Ii
iCheck
Integrity check. Reveals if the signal is spatially compromised, e.g., because of data reduction, such as MP3 or AAC encoded at too low a bit rate.
IEC
International Electrotechnical Commission. A standardization commission. The IEC has issued the most crucial measurement standard regarding microphones, IEC 60.268 Sound system equipment – Part 4: Microphones.
Institute of Electrical and Electronics Engineers. Interest organization with recognized standardization groups. Stands among other things for Essential Ethernet Standards (IEEE 802-3).
IETF
Internet Engineering Task Force. An interest group that also develops standards and recommendations.
IGMP
Internet Group Management Protocol. A multicast protocol that ensures that individual data packets are routed directly to the addresses for which they are intended.
IM
Intermodulation (see this).
Immersive Audio
Audio that generates immersion. Earlier, the expression “surround sound” was used; however, now immersive audio encompasses all sorts of audio formats that envelops the listener.
Impedance
Impedance is the complex load or complex input/output characteristics. The term indicates that the input- or output resistance of a circuit is not necessarily constant with frequency.
Matching the impedance of an input with the impedance of an input. When matched, maximum power is transferred from one circuit to the other. Impedance matching is mostly relevant for RF (transmitter-antenna and antenna-receiver) and electrical-coupled digital interfaces (like AES3 and the like). The long run of AF-cables, however, also takes advantage of impedance matching.
Impulse Response
The response of a system to a unit impulse. The Fourier transform of the impulse response is the frequency response.
See Transient.
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 2.5 kHz for the main system.
In-Phase
Two periodic waves reaching peaks and going through zero at the same instant are said to be in phase.
The property that an electrical current is produced in a conductor when it is exposed to a varying magnetic field.
Inductor
Coil wound on an iron core.
Infrasound
Sound at frequencies below the audible range, i.e. below about 16-20 Hz.
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. The code is found in the IEC standard 60529. The code is constructed from digits and letters: Code letters First characteristic numeral: Solid particle protection Second digit: Liquid ingress protection IP (International Protection) Single numeral: 0–6 or letter X Single numeral: 0–8 or letter X Mandatory Mandatory Mandatory DPA´s 6000 Series Subminiature Microphones conform to IP58, which means:
5: Ingress of dust is not entirely prevented, but it must not enter in sufficient quantity to interfere with the satisfactory operation of the equipment.
8: Immersion, 1 meter (3 ft 3 in) or more depth. The equipment is suitable for continuous immersion in water under conditions which shall be specified by the manufacturer. However, with certain types of equipment, it can mean that water can enter but only in such a manner that it produces no harmful effects. The test depth and duration is expected to be greater than the requirements for IPx7, and other environmental effects may be added, such as temperature cycling before immersion.
Depth specified by the manufacturer, generally up to 3 meters (9.8 ft)
Inherent Noise
Noise that is internally generated in a system in the absence of any excitation. For a microphone, usually expressed as an equivalent sound pressure level which would produce the same output voltage as the noise voltage. Also called self-noise.
This occurs when two or more frequencies are supplied to a non-linear system. The spectrum at the output of the non-linear device will, in addition to the original signal, also contain the sum and difference of the input signals along with their harmonics.
Internality
An environment descriptor in audio assessment.
The distinctness to which a sound source, ensemble or scene is perceived inside the head. Distinctly internal means that a sound is unambiguously perceived within the head. Distinct external means that a sound is unambiguous perceived outside the head. If it is ambiguous whether the sound is perceived to be inside or outside of the head, the internality is Indistinct.
A dry sample played equally to both ears over headphone may be perceived inside the head. Naturally occurring sounds are generally perceived externally.
Scale applied in listening tests: Distinctly internal- Indistinct - Distinctly external
[Reference: Report ITU-R BS.2399-0]
Internet protocol (IP)
That part of a network-based system, that describes the structure.
Interpolation
Computation of intermediate values in relation to fixed values (for example, values between two samples).
Interstitial
In broadcast: Name for a short-form program with a duration typical less than 60 sec.
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. This behavior occurs in free-field situations where the sound pressure level decreases 6 dB with each doubling of distance from the source.
IP
1 Internet Protocol (see this). 2 Ingress Protection (see Ingress Protection Code)
ips
Inches per second.
IPv4
Present standard for Internet Protocol. Limited by the still growing demand for unique IP-addresses which is beyond what this standard can deliver.
IPv6
A revised standard that provides far more unique IP-addresses compared to IPv4.
IR
1. Infrared (light). Frequency range approximately 10^12 to 10^14 Hz. IR light is used as a control signal in remote control units.
2. Impulse Response. The impulse response of a room contains the acoustic information of that room in the position where measured. Impulse response of rooms also applies to convolutional reverbs which generates reverb of actual rooms. Further, the impulse response of the microphones is measured. This is a tool used in microphone development, however, seldom published as the results from different brands are hardly comparable.
ISO
International Standards Organization; the international organization for standardization.
Isolation
Resistance to the transmission of sound by materials and structures.
ISRC
International Standard Recording Code. Information about the country of origin, the owner, the year of recording and the serial number of a recording encoded on compact disc.
ITDG
Initial Time Delay Gap (see this).
ITU
International Telecommunication Union.
Jj
Most popular terms
See all in J
Microphone Dictionary
Jj
Jack Plug
One-legged connector with two or three contacts. Normal dimensions are 6 / 3.5 / 2.5 mm (.24 / .14 / .1 in).
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. Jitter is measured in seconds (typical ns or ps). Jitter causes noise in the signal reproduced. The worst kind of jitter is sampling jitter, as this cannot be corrected later. To some degree, transmission jitter can be compensated for.
Abbreviation for the SI prefix kilo (10^3). See this.
K-weighting
The K-weighting applies to the loudness measurement of program material. Each channel passes this filter before calculating the summed Leq (equivalent level, see Leq.
Figure 1 Response of the K-weighting function.
kbps or kb/s
Kilobits per second.
kHz, Kiloherz
One thousand hertz.
See Hertz.
kilo
SI prefix kilo (10^3) like in kΩ (kiloohms). Or in data storage kilo (2^10): 1 kB = 1024 B. (See Numbers in audio).
Lavalier
Headset & Earset
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