A440 – a standard method of tuning in which the note A above Middle C has a frequency of 440 Hz (cycles per second). In 1936, ANSI adopted the standard establishing 440 Hz for the pitch of A above Middle C. Previously, a variety of tuning methods were in existence, with A having frequencies ranging from 373 Hz to 457 Hz. ISO adopted this standard in 1955. Sometimes designated as A=440 or A-440. Also called standard pitch or concert pitch.
A&R – Artists and Repertoire. The department or individual at a record label that manages the talent (Artists) and the music they write or perform (Repertoire). It is the job of the A&R person to scout, select, and sign performers to the label, as well as act as the liaison between the artist and label. Although specific duties vary by label, A&R people may also decide what songs to record, select musicians to work with the artist, and help with arranging and performing the music.
AAE – Avid Audio Engine. The underlying code designed by Avid that allows Pro Tools to communicate with computer hardware and software. Pro Tools is basically an user interface that tells the AAE (which runs in the background) what needs to be done. Prior to Pro Tools 11, the audio engine was the DAE (Digidesign Audio Engine), but beginning with PT 11 which upgraded to 64-bit, an all new audio engine was developed.
AAX – Avid Audio eXtension. The new plug-in format for Pro Tools, which replaces RTAS and TDM. Avid claims it offers better workflows and sound parity when sharing sessions between native and HD versions of Pro Tools. AAX comes in two versions: AAX DSP (compatible only with Pro Tools|HDX systems) and AAX Native (compatible with both Pro Tools and Pro Tools HD for PT 10 and above. TDM is not supported in Pro Tools|HDX. Pro Tools 11 and above requires the 64-bit version of AAX, sometimes referred to as AAX 2.
A-B – the procedure for comparing the sound of two different audio sources, by first listening to one source (A) and then quickly switching to the second (B). For the best accuracy, both sources should be at the same level. See also ABX.
A-B-C stereo, A/B/C stereo, or ABC stereo – see Decca tree.
Ableton AG – a music software company based in Berlin, Germany, that produces and distributes the software program Ableton Live, as well as a collection of related instruments and sample libraries. Ableton was founded in 1999 by Gerhard Behles, Robert Henke, and Bernd Roggendorf.
Abbey Road Studios – a recording studio located at 3 Abbey Road, Westminster, a suburb of London, England. Abbey Road Studios is noted for its innovative recording techniques developed by its engineers in conjunction with the Beatles (who recorded most of their albums and singles there), Pink Floyd, the Hollies, and other bands during the 1960s. The building began as a nine-bedroom townhouse built in the 1830s, but was later converted to flats (apartments). In 1931, the building was purchased by the Gramophone Company who converted it into recording studios. The same year, the Gramophone Company merged with the Columbia Graphophone Company to form EMI and the facility was named EMI Studios. After the Beatles released their album entitled Abbey Road in September 1969, the studios received world-wide attention, and in 1970 the building was renamed Abbey Road Studios. In 2010, the British government granted it historical status, preventing it from being sold to real estate developers. In 2012, the studio became the property of Universal Music with its acquisition of EMI.
Abfusor™ – a trademark of RPG Diffusor Systems for a panel that has both absorption and diffusion properties.
absolute grid mode – an editing mode in a DAW that allows movement and alignment of clips to specific points along a grid with user-defined increments. See also relative grid mode.
absolute measurement – the measurement of a quantitiy starting from zero or a known starting point. For example, the measurment of a voltage is the number of volts above zero volts, while the height of a building is the distance from street level (starting point) to the top of the building. In contract, a relative measurement is the measurement of a change in a quantity or in relation to another item or device. For example, the gain of an amplifier is the change in voltage from the input to output.
absolute pitch – the ability to identify or reproduce a musical note without using a reference pitch.
absolute time – the measure of elapsed time from the beginning of the tape, disc, or other media, usually measured in hours, minutes, seconds, and frames. Abbreviated as A-time.
absolute time code (ATC) – a timecode recorded in the subcode or control track of a digital tape. Almost all digital tape machines record it automatically. ATC is used to perform a variety of functions on digital tape such as autolocation, which locates specific points on a tape, and to synchronize the tape to other equipment. ATC usually can be converted to SMPTE timecode, but unlike SMPTE timecode, ATC always begins at zero at the beginning of a digital tape and increments frame by frame until recording stops.
absorb – to take in a sound wave rather than passing it through or reflecting it.
absorption – the process of taking in a sound wave rather than passing it through or reflecting it. Sometimes called acoustic absorption.
absorption coefficient (a) – the ability of a material to absorbsound waves at a particular frequency, with a higher coefficient indicating better acoustical damping. Sometimes called a sound absorption coefficient and abbreviated SAC.
A/B switch – a switch with one input and two outputs (A and B) or one output and two inputs (A and B), which allows the user manually to select between two inputs or outputs. For example, it can be used to select between two sets of studio monitors or to connect two devices to one computer. Also called an AB switch, A-B switch, A/B box, AB box , A-B box, A/B switch box, AB switch box, or A-B switch box. See also A/B/Y switch.
ABX testing – a type of double-blind testing in which a subject hears audio sample A, then audio sample B, followed by audio sample X. The subject must determine whether X is A or B. It is a double-blind test because neither the tester nor the subject knows which source is A, B, or X. Also called ABY testing or double-blind comparator. See also A-B.
Academy leader – a film leader with the standard visual countdown preceding a movie, counting down from 10 to 3. It is used for alignment and timing purposes, including the start of the first reel and for the change-over from one reel to the next during projection. Named after the Academy of Motion Picture Arts and Sciences, which establishes motion picture standards. Also called a SMPTE leader.
Academy of Motion Picture Arts and Sciences (AMPAS) – a professional honorary association formed for the advancement of the movie industry, composed of more than 6,000 motion picture professionals. The Academy is probably best known for its annual presentation of the Academy Awards, now officially known as “The Oscars.”
a cappella – music that consists only of one or more voices, without any instrumental accompaniment.
access jack – either two separate 2-conductorjacks or one 3-conductor jack on a mixer that allow the signal to be routed from the inputchannel to an outboardprocessor and then return back to the input channel. Inserting a plug into the access jacks breaks the signal flow and inserts a signal processor in series with the signal. Also called an insert jack. See also insert, definitions #2 and #3, and insert cable.
accompaniment – a vocal or instrumental part that supports and enhances another musical part, often a solo. For example, a piano is often used to provide an accompaniment for a solo singer or an instrument such as a violin.
accordion – a hand-held musical instrument that produces sound by air passing over metal reeds blown by bellows that are squeezed by the player. Notes are played by means of keys and buttons. There are three basic types of accordions: (a) the piano accordion, (b) the chromatic accordion, and (c) the diatonic accordion. The piano accordion, the type most familiar to Americans, has a piano-style keyboard for the right hand and an array of buttons for bass accompaniment for the left hand. A full-size piano accordion has 41 treble keys and 120 to 140 bass buttons. Chromatic accordions, more common in Europe, have buttons for both hands, treble for the right hand and bass for the left hand. Diatonic accordions (also known as melodeons) have buttons for both hands, but are pitched in a single key.
acetate – a type of phonographrecord widely used from the 1930s through the 1950s for recording and broadcast purposes and still used occasionally today. An acetate blank consists of an aluminum disc coated with nitrocellulose lacquer—not acetate. An acetate record is created using a recording lathe to cut a sound-modulated groove into the surface of the blank disc. An acetate master can be electroplated to create a stamper, which is used to press large quantities of regular vinyl records. Acetates also have been used for testing the quality of a tape-to-disc transfers, for comparing different takes or mixes, or for providing early preview copies of new singles to influential radio stationdisc jockeys. Although they can be played on a normal phonograph, they are much more susceptible to rapid wear than a vinyl record. Since they are usually created for special purposes and almost never sold to the general public, some acetates are highly prized because of their rarity. Also called an acetate disc, a test acetate, a lacquer (technically correct and preferred by the recording industry), a transcription disc, and an instantaneous disc.
acoustic – (1) Pertaining to sound audible by the human ear or the sense of hearing. (2) Pertaining to a musical instruments without electrical amplification, such as an acoustic guitar. (3) Pertaining to musicians playing musical instruments without electrical amplification. (4) The properties or qualities of a room that determine how sound is transmitted within it. (5) A musical instrument without electrical amplification. (6) Referring to the acoustic recording method.
acoustical engineer – an engineer that works with sound and vibration and the applications of acoustics. Acoustical engineers typically deals with the design, analysis, and control of sound. Also called an acoustic engineer.
acoustic amplifier – (1) The part of an instrument that intensifies the sound emanating from it. For example, the body of a violin or acoustic guitar. (2) A device that amplifies sound without using electricity, such as an acoustic horn.
acoustic-electric guitar – an acoustic guitar equipped with a pickup to amplify of the guitar signal. Often a piezo pickup is used, but sometimes a hybrid system is used that blends the signal from both a piezo pickup and an internal microphone. Also called an electro-acoustic guitar.
acoustic guitar – an ordinary guitar, which produces sound through its soundboard, as opposed to an electric guitar, whose sound is amplified by electronic means. Although some acoustic guitars have jacks that allow attachment to an amplifier, they are still considered acoustic because they produce sound in the normal manner in the absence of an amplifier.
acoustic horn – a cone-shaped device used to maximize the transfer of sound into air without the use of electronics. Acoustic horns can work in either direction, both increasing the intensity of a sound or being used at the receiving end to optimize the transfer of sound from the air to a receiver, such as used in early recordings. Acoustic horns have many applications, including phonograph horns, megaphones, vehicle horns, ear horns (for the hard of hearing), and horn-loaded loudspeakers.
acoustic impedance – the measure of the opposition that a system presents to acoustic flow from a sound pressure applied to the system, somewhat analogous to electrical impedance. Acoustic impedance consists of acoustic resistance (the real component) and acoustic reactance (the imaginary component). The acoustic impedance (Z) of a given material is calculated as Z = p × V, where p is the density of the material and V is the acoustic velocity.
acoustic lens – a mechanism used to improve the dispersion of high frequencies in loudspeakers creating a more uniform dispersion across the audio spectrum. Developed by Bell Laboratories during World War II, the objective of the acoustic lens is to focus sound just as an optical lens focuses light.
acoustic load – the additional stiffness on a loudspeaker caused by the volume of air in the enclosure. For low frequencies, this additional stiffness can be four times the stiffness of the speaker cone. The increased internal air stiffness is caused by the walls of the enclosure imposing zero airspeed on the air within the enclosure.
acoustic percussion – a term used to distingush actual percussioninstruments that are played by striking with a hand, stick, or beater, or by shaking, from electronic or programmed percussion instruments. Included in this group are acoustic drums.
acoustic recording – the method of recording in use during the acoustic era, from the time of Thomas Edison until the advent of electrical recordings in 1925. With this technique, all the energy used to create a recording came only from sound waves, with no electrical enhancements. Sound was collected using an acoustic horn with an attached stylus that transferred the sound vibration onto the surface of a cylinder or disc. Because there were no volume controls, mixing was done by arranging the singers and musicians in such a way to provide the best blend for the recording. Also called mechanical recording.
Acoustic Research – a high-end audio equipment company based in Cambridge, Massachusetts, that was well-known for its line of acoustic suspensionloudspeakers. AR was the first company to produce loudspeakers with a flat response, extended bass, wide dispersion, small size, and at a reasonable cost. The brand is now owned by VOXX International.
acoustic shadow – an area in which sound waves are greatly reduced, due obstructions, such as walls, or disruptions, such as wind currents. It is analogous to a shadow caused by the obstruction of light. See also head shadow.
acoustic suspension – a type of loudspeaker developed by Acoustic Research (AR) in which the speaker cone is attached to the mounting ring with an elastic material in a sealed enclosure. Unlike a conventional speaker with a stiff suspension, the air trapped inside the sealed-enclosure provides a more linear restoration of the speaker diaphragm and allows greater cone excursions, producing deeper bass tones with relatively smaller cones. Unfortunately this design results in a less efficient speaker system requiring more amplifier power. Althougn acoustic suspension speakers were at one time extremely popular in stereo systems because of their low distortion, bass reflex speakers have become more common as the design of speakers with ported enclosures has improved.
acoustic theory – the study of acoustics using a mathematical description of sound waves as derived from fluid dynamics.
acoustic tile – a ceiling tile made of soft, sound-absorbing material, often having a pattern of small, regularly or irregularly spaced holes. Acoustic tiles can be hung using a ceiling suspension system, installed directly over an existing ceiling, or attached to a wall. The purpose is to dampen echoes and reverberations and reduce exterior noise. Acoustic tile is commonly used in churches, schools, theaters, and concert halls, but rarely in recording studios, which require more sophisticated acoustic treatments. Also called acoustical tile.
acoustic treatment – various devices and methods used to control the sound properties (temporal, spectral, and spatial qualities) in a space. There are three main categories of acoustic treatment: (a) absorption, (b) diffusion, and (c) isolation. These treatments are used to control reflections and prevent sounds from interfering with one another, as well as to prevent sounds from entering or leaving the space (isolation). The goal of acoustic treatment is to have a space with an essentially flat response and with minimal coloration contributed by the room. Room problems are related to room dimensions (see room ratios), construction materials, and surface finishes. Acoustic problems are usually divided into two classes: (1) low frequency problems and (2) midrange and high-frequency problems. Low-frequency issues are related to standing waves (room modes) and are usually treated with bass traps, such as Helmholtz resonators and membrane absorbers. Higher-frequency problems are due to reflections that cause echoes and reverberations. These problems are typically treated using absorption and diffusion. In the absence of acoustic treatment, most spaces tend to accentuate some frequencies and attenuate others.
action – (1) On stringed instruments, such as a guitar, the distance between the fingerboard and the strings. When the strings are far above the fingerboard, it is called high action. When the strings are close to the fingerboard, it is called low action. Guitars with low action are easier to play, but if they are too close can cause fret buzz. (2) On keyboard instruments, the mechanism that causes a string to be struck or plucked when a key is depressed.
active sensing – a system used to verify that a MIDI connection is functioning, consisting of sending a signal to a MIDI device, and if no response is received within a specified period (typically 300 ms), all notes are switched off preventing notes from hanging when communication is lost. Active sensing is supported by only a few MIDI devices.
adapter – (1) A connector that enables two otherwise incompatible connectors to connect, such as an adapter that converts a XLR to a TRS plug. (2) An electrical plug that has provides two or three outlets. Usually called a plug adapter. (3) A power adapter. Sometimes spelled adaptor.
ADAT DOI – ADAT Digital Optical Interface. The digital communication standard designed by Alesis that uses an optical cable (which Alesis calls a Lightpipe) to transfer signals between ADAT units. This system has since been adopted by other manufacturers as a means of transferring digitalsignals between various types of audio devices. It is capable of transmitting eight channels of digital audio with sample rates of 44.1 kHz and 24-bit resolution on a single cable, or four channels at 96 kHz. Also known as ADAT Optical and often simply called ADAT for short. See also TDIF, TOSlink, and S/PDIF.
ADAT/FST – ADAT/File Streaming Technology. ADAT/FST is a protocol developed by Alesis for their HD24 24-trackhard diskdigital recording system. Instead of using typical FAT-32 or HFS hard drive formatting, Alesis developed a method to record data in a linear manner in which all the data for a recorded track remains together in associated clusters and does not become fragmented or separated from related data.
additive flanging – flanging in which the delayedsignal is added to the dry signal, as opposed subtractive flanging which subtracts the delayed signal from the dry signal (or adds a signal that is 180° out of phase). While the results of these two opposite operations can be similar, it can dramatically change the character of the sound depending on the frequency content and harmonics in the signal. Subtractive flanging tends to be more pronounced than additive flanging. Additive and subtractive flanging are sometimes called positive and negative flanging, respectively.
AD/DA converter – (1) A term referring to both analog-to-digital converters and digital-to-analog converters. (2) A converter that does both analog-to-digital conversion and digital-to-analog conversion. Sometimes shown as A/D and D/A converter, AD-DA converter, or ADDA converter.
Adobe Media Server (AMS) – a data and media server provided by Adobe (previously by Macromedia) that works with the Flash Player to create multiuser media applications. It was previously known as Flash Communication Server and Flash Media Server.
Adobe Systems Incorporated – a multinational computer software company founded in 1982 by John Warnock and Charles Geschke and headquartered in San Jose, California. Adobe develops software for multimedia and creativity products and internet applications. It is probably best known for creating the portable document format (PDF).
Advanced Audio Coding (AAC) – a method of compressing and encodingdigital audio developed by Bell Laboratories, Fraunhofer Institute, Dolby Labs, Sony, and Nokia. It is designed to achieve better sound quality than MP3 at similar bit rates and file sizes. AAC has been made part of the MPEG-2 and MPEG-4 specifications. There are several types (profiles) of AAC encoding used for various applications, which are usually automatically selected by the encoder based on encoding options: AAC-LC (Low Complexity) profile, which is suitable for higher compression ratios, AAC-LD (Low Delay) profile which optimizes playback speed, used for real-time applications such as telephones, and HE-AAC (High Efficiency) profile, which has enhanced features.
Advent Corporation – a consumer electronics company founded by Henry Kloss in 1967. It manufactured loudspeakers, televisions, cassette players, and other electronic devices. In 1981, long after Kloss had left Advent, the company went into bankruptcy, and it was acquired by Jensen Electronics. In 2004, Jensen was acquired by Audiovox, which became VOXX International in 2012.
Aeolian mode – one of the seven musical modes or scales with the interval pattern of tone-semitone-tone-tone-semitone-tone-tone. This is also known as the natural minor scale.
AES3 – a professional audio standard for an interface developed jointly by the Audio Engineering Society (AES) and the European Broadcast Union (EBU), formerly known as AES/EBU. The standard provides the technical details for transmitting digitalaudio signals via a cable. There are three types of connection in common use: (a) Type I - Balanced XLR, (b) Type II - Unbalanced RCA, and (c) Type III - Optical. Type I connections use balanced, 3-conductor, 110-ohm twisted pair cables with XLR connectors, typically used in professional installations. They are considered the AES3 standard connector. Type II connections use unbalanced, 2-conductor, 75-ohm coaxial cables with RCA connectors, typically used in consumer audio installations. They are known as S/PDIF connections. Type III use fiber-optic cables, commonly known as TOSlink cables. Type III optical connections are used in both professional and consumer audio equipment. They are also known as optical S/PDIF connections.
AES3id – a subset of the AES3 (AES/EBU) digital audio interface standard with different hardware requirements. While AES3 specifies balanced 110-ohm connections, AES3id specifies unbalanced 75-ohm connections, the same as as S/PDIF connections, except AES3id usually uses BNC connections rather than RCA connectors. The data contained in the transmission using both formats are identical.
AES31 – a standard established by the Audio Engineering Society (AES) for the interchange of digital audio projects between different systems, especially audio editing projects between DAWs. The standard is divided into three parts. Part 1 specifies the disk format. Part 2 defines the file format. Part 3 defines a standard for edit decision lists.
a standard established by the AES as a standardized method for packing AES3 professional digital audio streams over Asynchronous Transfer Mode (ATM) networks.
AES51 – a standard established by AES that specifies a method of carrying Asynchronous Transfer Mode (ATM) cells over Ethernet for use with AES47 to carry AES3digital audio transport structure. The purpose of this is to provide an open standarid, Ethernet-based approach to the networking of linear (uncompressed) digital audio with extremely high quality-of-service along with standard Internet Protocol connections.
AES67 – a standard established by AES for audio over IP (AoIP) and audio over ethernet (AoE) interoperability. It specifies a baseline set of protocols to enable synchronized audio connectivity between AoIP and AoE using various using various audio networking systems, such as standards for clock synchronization, quality of service, and methods to bridge between different AoIP implementations.
AES70 – a standard established by AES for Open Control Architecture (OCA), a communications protocol, originally proposed by the OCA Alliance in January 2016, to control, monitor, and manage connections of media networks (networked audio and video devices). It allows for the creation and deletion of signal paths, access control, control of processing, and firmware updates. Control can be via wired Ethernet or WiFi. OCA is an open standard that requires no licenses, fees, or memberships.
after fade listen (AFL) – a signal taken after the main channel fader on consoles and mixers. This signal point allows the operator to listen after the main fader level. Also called post fade listen, but since PFL indicates pre fade listen, AFL is used for this abbreviation. See also APL and PFL.
aftertouch – MIDI data sent from a keyboard when pressure is applied to a key after it has been struck and is being held down or sustained. Aftertouch can be used to control vibrato, volume, and other parameters. Also called pressure sensitivity. See also keyboard expression.
AFTRA – American Federation of Television and Radio Artists. See SAG-AFTRA.
AIFF – Audio Interchange File Format. AIFF is an audio file format used by Apple for storing sound data on computers and other electronic audio devices. These files use the .aif extension and are most commonly used on Apple Macintosh computer systems. See also BWF and WAV.
air gap – a security method in which one or more computers are physically isolated from unsecured networks, such as the internet or unsecured local area networks. An air gap can be either physically separated computers or computers that use dedicated cryptographic methods to prevent computers on opposite sides of the gap from communicating. Also called air wall or air gapping.
air motion transformer (AMT) – a type of loudspeakerdriver, invented by Dr. Oskar Heil, that operates similar to but different from a ribbon driver, consisting of a
ribbon made of polyethylene, polyester, or polyimide, folded into an accordion pleat and positioned within a high-intensity magnetic field. It opens and closes in a manner similar to human vocal cords so that it “squeezes” air molecules rather than pushing them.
airplay – (1) Broadcast time given to the playing of a song, movie, or other recording. (2) Exposure on broadcast radio.
airy – a descriptive term for a sound with the feeling of spaciousness or openess, a quality that allows the sound to breathe a little, usually affected by frequencies above 12 kHz. Compare with shimmer.
Akai – a consumer electronics company founded in 1929 as Akai Electric Company, Ltd. In 2000, the business, which had fallen on hard times, began to license the Akai name to rebrand electronics manufactured by other companies, and is now headquartered in Singapore. Akai Professional separated from the consumer products company in 1999 and is no longer associated with it.
Akai Professional – a company manufacturing and selling electronic instruments and recording equipment, that began business as a new division of Akai in 1984. In 1999, Akai Professional was acquired by a US company and became Akai Professional Musical Instrument Corporation, but it went bankrupted in 2005. It was acquired by Numark Industries and Alesis. In 2012, Numark, including Akai Professional, became a part of inMusic Brands.
AKG Acoustics – a company founded in Vienna, Austria, in 1947 as Akustische und Kino-Gerate Gesellschaft m.b.H. (Acoustic and Cinema Equipment). Today it is an American-owned manufacturer of consumer and professional audio products, such as microphones, headphones, and wireless microphones. The company was acquired by the American company Harman International Industries in 1994.
AKG C 12 – a tubecondenser microphone introduced by AKG in 1953, using the legendary CK12 microphone capsule. It made AKG one of two dominant forces in the manufacture of commercial condenser microphones, the other being Neumann. When Neumann stopped distributing the U 47 under the Telefunken name in 1958, Telefunken needed a replacement microphone. AKG agreed to supply them the C 12, which was marketed as the ELA M 250 and ELA M 251. However, whereas the C 12 polar patterns could be changed remotely by varying the polarizing voltage, the ELA M models used switches. The 250 had omni and cardioid patterns, while the 251 had omni, cardioid, and figure 8. The ELA Ms were slightly different from the C 12 in the circuitry, as well as the head grilles.
AKG C 414 – a condenser microphone introduced by AKG in 1971. The C 414 was a successor to the C-12 and was the first commercial solid-state condenser microphone. Since 1971 the microphone has retained the C 414 designation, but subsequent upgrades and changes in technology have been denoted by new suffixes. By some counts, there have been more than a dozen iterations, including C 414EB, C 414EB-P48, C 414 B-ULS, C 414 B-TL II, C 414 B-XLS, C 414 B-XL II, C 414 XLS, and C 414 XL II.
AKG D 12 – a cardioiddynamic microphone introduced by AKG in 1953. It was the world's first dynamic cardioid microphone. Although ooriginally a vocal mic, its unique design and sound established the D 12 as the standard microphone for recording kick drums and bass instruments. The design includes a special bass chamber, a cannister below the moving-coilcapsule connected to it acoustically by a small tube, which boosts the frequencies in the 60 to 120 Hz range. Introduced later, the AKG D 12E was a similar mic with a few modifications, including the addition of an XLR connection.
album – a collection of audio tracks, usually by the same artist, or a compilation of music by several artists connected by a common genre or theme. Originally, an album was a collection of 10-inch 78-rpm records bundled together into a book resembling a picture album. Later the term was applied to the 33⅔-rpm vinyl LP in which a collection of tracks were assembled on the front and back of a single disc and on occasion more than one disc. Today a compact disc usually is considered an album if it contains ten or more tracks. Fewer tracks are termed an EP, usually numbering four to six tracks.
Alesis – a company based in Cumberland, Rhode Island, that designs and markets electronic musical instruments, digital audio processors, audio mixers, and other professional audio and recording equipment. Founded in 1984 as Alesis Studio Electronics in Hollywood, California, it is now a part of the inMusic Brands.
alias – (1) An alternative name for an object, such as a file, variable, or device. On Macintosh computers, an alias can be assigned for files, which allows the use of an icon for the same file in different folders. Windows provides the same functionality, but calls it a shortcut. (2) A false signal that can be created with digital audio data in a process called aliasing.
all-button mode – using all four of the pushbuttons designed for selecting compression ratios on a Universal Audio 1176compressor (previously the UREI 1176). The 1176 has buttons for selecting ratios of 4:1, 8:1, 12:1 and 20:1. An unknown British engineer tried pushing all four buttons at the same time, which significantly increased overdrivendistortion. This unique sound soon became widely copied in rock music mixes. Other compressor manufacturers have attempted to imitate it. It is typically used on drums, guitar, and bass to produce a dirty sound and sometimes even on vocals. The Universal Audio 1176LN plug-in software actually includes a digital emulation of the all-button mode. Sometimes called the all buttons in, four-button mode, four-buttons in, four-button trick, or British mode.
allegretto – a musical term indicating a moderately fast tempo, slower than allegro, typically 98 to 128 bpm. See chart of tempo terms.
allegro – a musical term indicating a moderately fast, quick, and bright tempo, typically 109 to 168 bpm. See chart of tempo terms.
Allen & Heath (AH or A&H) – a company founded in 1969 and headquartered in Penryn, Cornwall, England, that manufactures audiomixers, mixing consoles, and sound management systems for industrial installations. Allen & Heath is now part of Audiotonix.
alligator clip – a spring metal clip with long, serrated jaws attached to a wire or cable used for making temporary connections to batteries, speakers and other devices. It is named for its resemblance to the jaws of an alligator. Also called a crocodile clip or spring clip.
Allison effect – the destructive interference pattern that occurs when a sound source is located one-quarter wavelength away from a reflective surface. Named for Roy F. Allison, an acoustic engineer with Acoustic Research (AR).
allpass filter – a signal processingfilter designed to change the phase relationship between various frequencies, but keep the level of all frequencies essentially equal. Sometimes spelled as the less-preferred all-pass filter.
Altec Lansing – a company founded in 1941 that makes loudspeakers and associated audioelectronics for professional, home, automotive, and multimedia applications. Motion picturesound was developed by a group of engineers at Western Electric, who formed the All Technical Products Company, in 1936. The named was changed to Altec Services Company in 1937. Altec purchased the nearly bankrupt Lansing Manufacturing Company and formed the Altec Lansing Corporation in 1941. Originally, the company serviced movie theater sound systems, but soon began manufacturing loudspeakers. They also made studio monitors from the 1940s to the 1980s. The Altec Voice of the Theater line of loudspeakers was widely used in movie theaters, concert halls, and rock concerts from the 1960s to the 1990s. In 1958, Altec was bought by James Ling, and it was moved to Anaheim, CA. In 1974 Ling spun Altec Lansing from his company, LTV-Ling-Altec. In 1984, Gulton purchased Altec Sound Products Division out of bankruptcy from the Altec Lansing Corporation. The movie theater sound installation and repair business, Altec Service Co., was sold to J. Bruce Waddell and Robert V. Gandolfi, who changed the name to ASC Technical Services. In 1995, Telex Comunications purchased Altec Lansing's parent company, EVI Audio, Inc. In 2000, it was sold to Sparkomatic and it became Altec Lansing Technologies. In 2005, Altec Lansing Technologies was acquired by Plantronics. In 2008, the company was reorganized becoming Altec Lansing LLC. In 2009, it was acquired by Prophet Equity, and in 2012, by the Infinity Group, which specializes in acquiring and turning around struggling or bankrupt consumer brands.
alternate picking – a guitar playing technique that continuously alternates between downward and upward picking strokes, the most common method of guitar picking. When the technique is used on a single note at a high speed, it is usually referred to as tremolo picking.
alternate tuning – a method of tuning the strings of an instrument in a different manner from standard tuning. For the guitar, standard tuning is EADGBE. One well-known alternate tuning for acoustic guitar is Celtic tuning (DADGAD, commonly called “dadgad”). Another type of alternate tunings are the dropped tunings, such as dropped D (DADGBE), where the low E string is tuned down (dropped) to D and double drop D (DADGBD) in which both E strings are dropped to D. Open tuning is another type of alternate tuning. Also called altered tuning, alternative tuning, or scordatura.
alternating current (ac) – electric current that reverses direction at regularly recurring intervals of time, typically 60 Hz in the US and 50 Hz in the UK. Official abbreviation is ac, but AC is commonly used. Contrast with direct current.
alto – (1) The lowest vocal range of the adult female voice, usually a range from about G below Middle C to about F above High C (G3 to F5). (2) The musical range between soprano and tenor. (3) A singer whose voice is within this range. (4) A musical instrument that plays within this range. (5) A vocal or instrumental part written in this range. (6) Another name for the viola.
alto clef – the symbol on a music staff indicating that the third line from the bottom of a staff represents the pitch of middle C. It is one of five C clefs and is used primarily for writing music for the viola. Also called a viola clef.
ambience – (1) The sound that comes from the surrounding environment as opposed to coming directly from the sound source. (2) Background noise. See also ambient sound. Not to be confused with ambiance, which means the atmosphere or mood of a particular environment.
ambience extraction – a method of removing out-of-phase information from a two-channel audio signal and using it to created surround channels. David Hafler developed one of the early systems of ambience extraction in the early 1960s, with a process he called Dynaquad, marketed by Hafler's company, Dynaco. A few years later, Peter Scheiber patented a similar system that competed with quadraphonic sound in the early 1970s. Dolby Laboratories cited several of Scheiber's patents when it developed the Dolby surround system. Also called pseudo-quadraphonics, Hafler hookup, and ambiophony.
ambience track – the ambient sound of the sets and locations in which a scene was shot recorded by the sound editor to be used in the final mix of a motion picture or video production, used to make sure the background noise is consistent, without any unnatural changes.
ambient – (1) Pertainging to the surrounding environment. (2) A type of instrumental music designed to enhance the mood or atmosphere or induce calmness.
ambient sound – the background noises that are present in a scene or on location, such as wind, water, crowds, and traffic. Ambient sounds are important in video and film work because they provide audio continuity between shots, they prevent unnatural silence when there is no other sound, and they can be used to establish a mood. Also called ambient audio, ambient noise, ambience, atmosphere, atmos, background sounds, or background noise. See also location sound.
Ambisonics – various recording and playback techniques, developed in the UK in the 1970s by the British National Research Development Corporation, that use multichannelmixing technology to create a variety of surround sound effects. The sound data can be encoded and decoded to produce a 2-dimensional (horizontal-only) or 3-dimensional (full-sphere) sound field. Unlike other surround sound formats, Ambisonics is not encoded into signals for specific speakers, but contains representations of the sound field, called the B-format, that includes source directions instead of speaker positions. This technique allows for the signal to be decoded specifically for the speaker setup at a given location or venue, allowing for a considerable amount of flexibility in the number of speakers and their position. Until recently Ambisonics has not been much of a commercial success, but with the advent of more powerful digital signal processing (as opposed to the analogcircuitry used in the early years), interest in Ambisonics hs been increasing since the 1990s, especially with the advent of immersive sound. Ambisonics uses several interdependent audio tracks that can be decoded into most other end-user formats, such as stereo, 5.1 surround, 7.1 surround,immersive sound, etc. That means that only one Ambisonic recording or mix needs to be created to be used with the various formats. See also higher-order Ambisonics (HOA).
Ambisonics Channel Number (ACN) – a system for ordering the channels used in an Ambisonics format. ACN uses numerals instead of letters, with the order correspond to W X Y Z R S T U V... Unused channels are omitted.
American Association of Independent Music (A2IM) – a non-profit trade organization serving the independent music community by representing their interests in the marketplace, in the media, and in government affairs.
American Broadcasting Company (ABC) – a commercial US broadcasttelevisionnetwork headquartered in New York City, NY, and owned by the Disney-ABC Television Group, a subsidiary of Disney Media Networks division of The Walt Disney Company. ABC originated in 1943 as a radio network when Edward J. Noble, owner of Life Savers candy and Rexall Drugs, purchased the NBC Blue Network after the FCC ordered RCA to divest its ownership. The following year, Noble acquired the rights to the name American Broadcasting Company and began using the name American Broadcasting Companies, Inc., for the parent corporation. ABC launched its television network in 1948. In the mid-1950s, ABC merged with United Paramount Theatres, a subsidiary of Paramount Pictures. ABC merged with Capital Cities Communications in 1986. In 1996, most of Capital Cities/ABC's assets were purchased by The Walt Disney Company. In 2007, it sold the radio portion of the business to Citadel Broadcasting, becoming almost exclusively a television network.
American Federation of Musicians (AFM) – a union of performing artists and musicians. AFM membership guarantees that musicians will be paid at the minimum rate established by the union (union scale). Signatory companies (those having signed an agreement with AFM) can only hire union musicians and must pay union scale.
American Graphophone Company – a company founded in 1887 and licensed by the Volta Graphophone Company to manufacture the Graphophone. The Columbia Phonograph Company was founded in 1889 to sell the products manufactured by the American Graphophone Company. In 1895, the American Graphophone Company merged with the Columbia Phonograph Company, with the former conducting research and manufacturing and the latter managing marketing, sales, and distribution. The American Graphophone Company continued the manufacturer of Columbia products until 1916, when it was reorganized as the Columbia Graphophone Manufacturing Company.
American Loudspeaker Manufacturers Association (ALMA) – an international trade organization for companies that design, manufacture, sell, and test loudspeaker components and systems.
American National Standards Institute (ANSI) – a private non-profit organization that oversees the development of voluntary standards for products, services, systems, processes, and personnel in the United States. It began as a joint effort to avoid creating conflicting standards when in 1918
six standards organizations along with the the US departments of commerce, war, and the navy established the American Engineering Standards Committee (AESC). In 1928, it became the American Standards Association (ASA). In 1966, they reorganized and became the United States of America Standards Institute (USASI). The current name was adopted in 1969.
American Wire Gauge (AWG) – a set of standards used for measuring and specifying non-ferrous wire conductor sizes (diameters), used primarily in the US and Canada. The higher the gauge number, the smaller the diameter. AWG is used only for non-ferrous wire used to conduct electricity, such as copper and aluminum. Steel wire uses a different gauge (the Washburn & Moen Gauge, which is also called the American Steel and Wire Gauge, or Steel Wire Gauge for short). AWG is also known as the Brown & Sharpe wire gauge. Household wiring typically is 12 or 14 gauge, whereas studio and audio wiring is usually in the range of 16 to 22. Some diameters for a sampling of AWG values is shown below:
ammeter – an instrument used to measure the electric current in a circuit, usually in amperes or milliamperes.
amperage – the magnitude of an electrical current as expressed in amperes.
ampere – a unit for the measurement of electric current. One ampere equal to one coulomb of charges passing in one second (1 ampere = 1 coulomb/sec). Named for André-Marie Ampère. Abbreviated as A. Called amp for short.
ampere-hour (Ah) – the amount of electric charge equal to a steady current of one ampere flowing for one hour, or 3600 coulombs. The ampere-hour is used to measure the charge in electrochemical systems, such as electroplating and batteries. Also called amp-hour.
Ampex – a company founded by Alexander Matthew Poniatoff in 1944, as the Ampex Electric and Manufacturing Company. Ampex was one of the first companies to produce high-qulaity tape recorders. They also produced the first commercially successful videotape recorder, the
amplifier – an electronic device that increases the strength or level of an audio signal passing through it. Sometimes called an electric amplifier or electronic amplifier, to distinguish it from an acoustic amplifier, which amplifies sound by non-electical means.
amplifier classes – categorization of amplifiers by their circuit configuration and methods of operation. The main operating characteristics of an ideal amplifier are linearity, signal gain, efficiency, and power output. There are always trade offs between these characteristics. The class of amplifier is important in the recording studio because the different classes add differing amounts of distortion as well as somewhat pleasing harmonics. Amplifier classes fall into two main groups. The first group contains the classic designs which include class A, class B, class AB, and class C. The second group of amplifiers are the newer “switching” amplifier classes, such as class D, class E, class F, class G, class H, and class T. These classes use digital circuits and pulse width modulation (PWM) to constantly switch the signal between “fully-on” and “fully-off” modes.
amplifier profile – settings used to simulate a particular guitar amplifier setup. The Kemper Profiling Amplifier (KPA), designed by Christoph Kemper, founder of Access Music Electronics, captures the sonic characteristics of an amp by playing a series of test tones through it and making a digital analysis of the result. The analysis takes a “snapshot” of a specific setup (a particular amplifier/cabinet combination with controls set in a specific way and with a particular microphone setup). The KPA allows users to create and share such profiles. Profiles are said to be extremely accurate models of the original amplifier and speaker cabinet for a given set of conditions.
amplitude – the magnitude of change in the oscillation of a wave (especially sound waves or radio waves). It is the height of the wave as measured from an imaginary center line to the wave peak. For sound waves amplitude translates as loudness. See also wavelength and frequency.
AM rejection – the ability of an FM receiver to reject signals from AMtransmitters and AM noise generated by electrical devices and natural sources. Also called AM suppression.
AMS – Audio MIDI Setup. A utility program that comes with the Mac OS X operating system to set up the audio input/output (IO) configurations of the computer and to manage MIDI devices.
AMS Neve, Ltd. – a company headquartered in Burnley, Lancashire, UK, that designs and manufactures professional audio and recording equipment. It began as Neve Electronics, which was founded in the 1960s by Rupert Neve, who designed and built mixing consoles. Rupert Neve sold the company in 1973 to the Bonochord Group and left the company in 1975. Rupert Neve went into business as ARN Consultants, which eventually became Ruper Neve Design, LLC. In 1985 Neve Electronics was acquired by the Siemens group. Siemens then acquired Advanced Music Systems (AMS) and combined it with Neve Electronics in 1992 to form AMS Neve.
AM stereo – the broadcasting of stereophonic sound audio on the AM radio band using a technique that is compatible with standard AM receivers. In 1993 the FCC designated quadrature amplitude modulation (QAM) or (C-QUAM) (similar in concept to FM stereo) as the method for AM stereo broadcasts in the US. Although initially a large number of stations implemented stereo broadcasting, that number soon began to decline due to a lack of receivers and a migration of music to the FM radio band with AM becoming primarily news, talk, and sports programming.
analog – an electronic system that uses a continuously varying signal to represent a physical variable, such as the current produced by a microphone representing sound pressure, as opposed to digital, which uses a stream of binary digits to represent such a variable. The British spelling is analogue.
analog computer – a type of computer that uses models to solve problems by representing the data as a continuously variable physical phenomenon, such as electricl voltage or current, mechanical rotation of gears, or fluid flow. In contrast, digital computers solve problems using numerical values. British spelling analogue computer.
analog signal – a continuous signal in which a variable varies with time and is analogous to some other time-varying variable. For example, an analogaudio signal is a voltage signal that represents the varying pressure of sound waves. It differs from a digital signal in that the quantity is represented by binary digits and can have only one of a finite number of values. British spelling analogue signal.
analog television – the system in which televisionsignals were broadcast, received, and displayed using analog technology. The interlacedvideo portion of the signal was transmitted using AM, while the audio was transmitted using FM. In the US analog television broadcasting ended on June 12, 2009, except for a few educational or low-powered transmitters, and was replaced by digital television (DTV). See also NTSC and ATSC.
analog-to-digital conversion – the process of changing an analogsignal into a digital signal that contains essentially the same information, using an analog-to-digital converter. Abbreviated as AD conversion, A-D conversion, A/D conversion, and A-to-D conversion. British spelling analogue-to-digital conversion.
analog-to-digital converter – an electronic device or circuitry that converts an analogsignal into a digital datasteam. Audio quality depends very greatly on the accuracy of the analog-to-digital converter and the digital-to-analog converter. Abbreviated as AD converter, A-D converter, A/D converter, A-to-D converter, and ADC. British spelling analogue-to-digital converter.
anamorphic format – a system in which an image is recorded in a narrower aspect ratio to be subsequently displayed or projected in its original aspect ratio. For example, a widescreen picture can be shot on standard 35-mm film in a non-widescreen aspect ratio and then stretched back to the original widescreen aspect ratio when projected.
anechoic chamber – a room in which the reflection of sound waves are minimized and which is isolated from external sources of sound. An acousticallydead space. Also called an anechoic room. Sometimes called an acoustic anechoic chamber to distingish it from rooms used for waves other than sound, such as electromagnetic waves.
angular acceleration – the rate of increase or decrease in angular velocity. It is usually represented by the Greek letter alpha (α).
angular frequency (ω) – the measure of rotation rate, and can refer to circular rotation, oscillations of a wave, or the rate of change of a sine function, usually in units of radians per second. It is essentially the same as angular velocity without the directional component. It refers to the angular displacement per unit time (e.g., in rotation) or the rate of change of the phase of a sinusoidal waveform (e.g., in oscillations and waves), or as the rate of change of the argument of the sine function. Also called angular speed, radial frequency, circular frequency, orbital frequency, or radian frequency.
angular velocity (ω) – a vector quantity that specifies the rotational speed (angular speed) of an object and the direction of rotation, usually in units of radians per second. Other units are sometimes used, such as degrees per second or radians per hour. A vector specifies both speed and direction. The direction is perpendicular to the plane of the rotation. Compare with angular frequency, which is not a vector quantity. See also constant angular velocity.
anisotropy – the condition of having properties that are directionally dependent. It is the opposite of isotropy. Of particular concern with recording tape formulations is the anisotropy of magnetic particles, which can have preferred directions of magnetization. The anisotropy of these particles depend upon their shape, their crystalline structure, or the stress within them.
Antares Audio Technologies – a company located in Scotts Valley, CA, that develops and markets audio software and equipment. It was founded in 1990 as Jupiter Systems by Dr. Harold (Andy) Hildebrand. Antares is probably best known as the developer of Auto-Tune®.
antenna directivity – the measure of the directional characteristics of an antenna. The directional pattern depends on the antenna design, its size, the environment, and a variety of other factors. The pattern should be used to ensure that the signal is aimed in the desired direction. See also directional antenna.
antenna efficiency – the amount of power radiated by an antenna compared to the power delivered to the antenna or the amount of power delivered by an antenna compared to the power received by the antenna. Compare with antenna gain.
antenna gain – the ratio of the power produced by an antenna as compared to the power produced by a hypothetical lossless isotropic antenna, usually expressed in decibels-isotropic (dBi). Compare with antenna efficiency.
antenna splitter – a device that electrically matches one antenna to multiple receivers.
anticipation – a technique of melodic or rhythmic alteration in which a note is played slightly before the beat causing syncopation. When the anticipation occurs in the melody, it is called a melodic anticipation. An anticipation that occurs one-half beat early is called an eighth note anticipation. One that is a quarter of a beat early is a sixteenth note anticipation, while one-third of a beat early is a triplet anticipation. Also known as pushed notes, pushed beats, or simply pushes.
antiphonal – music played or sung interactively by two different groups of performers, often singing alternate musical phrases.
antiphony – a call and response style of singing.
antiquing – the process of making modern audio files sound as if they were old recordings or used older recording technology. The opposite of restoring old recordings.
anti-skating – a mechanism used on phonographs and turntables that compensates for the tendency of a tonearm to slide (skate) toward the center of the platter, thereby keeping the stylus in the groove. Also spelled antiskating.
aperiodic – (1) Occurring at irregular intervals. (2) A waveform that it not repetitive and, therefore, has no pitch. Opposite of periodic.
aperture time – the time it takes for the sample-and-hold (S/H) circuit in an A/D converter to determine the level of the signal waveform and to hold this value until the next sample. Because the time required to determine the next level depends on the amount of change in the signal, the aperture time will vary with the rate of signal level change, which increases for higher-frequency signals.
API 312 – a modular preamp designed and built by API for their API 500 series. It uses 2520 op amps and is based on the preamps used in the classic API consoles of the 1970s. With its extremely flat frequency response, it delivers a very pristine sound and is considered to be an extremely versatile preamp that some have called “legendary.”
API 550 – an equalizer designed by Saul Walker and introduced in 1968 by Automated Processes, Inc. It was first used in API custom-designed console and had a unique sound due to the custom-designed op amps and its proportional-Q circuitry, which automatically adjusted the bandwidth based on the amount of equalization applied, eliminating the need for a bandwidth adjustment and minimizing phase shift. It is a 500 series module. It was later replaced by the 550A and then the 550b.
apparent power – a measure of power in an alternating current (ac) circuit that is calculated by multiplying the root-mean-square (rms) current by the root-mean-square voltage. In a direct current (dc) circuit, or in an ac circuit where the impedance is pure resistance, the voltage and current are in phase, and power is calculated by multiplying the rms voltage in volts by the rms current in amperes and is expressed in watts. However, in an ac circuit whose impedance consists of reactance as well as resistance, the voltage and current are not in phase, and the product of the rms voltage and the rms current is called apparent power, and is expressed in volt-amperes. When the impedance is a pure resistance, the apparent power is the same as the true power, but when there is reactance, the apparent power is greater than the true power. The vector difference between the apparent and true power is called reactive power.
Apple Corps, Ltd – a multimedia company founded in London in 1968 by the Beatles. It replaced their former company, Beatles, Ltd. Its name (pronounced “apple core”) is a pun. Its main divisions are Apple Records (also launched in 1968), Apple Electronics, Apple Films, Apple Publishing, and Apple Retail.
Apple, Inc. – a multinational corporation headquartered in Cupertino, California, that designs, develops, and sells computers, consumer electronics, and computer software.
Apple Lossless Audio Codec (ALAC) – an audio codec developed by Apple, Inc., for lossless data compression of digital music. Although originally proprietary, it is now a free, open source format. It uses the .m4a file extension. Also called Apple Lossless and Apple Lossless Encoder (ALE).
Apple Music – a pay-for-services music and videostreaming service created by Apple Inc. in 2015. Similar to Pandora and Spotify, users can select music to stream to their device on-demand, or they can listen to existing, curated playlists.
application – a computer program, or group of programs, that is designed to to perform functions, tasks, or activities. Applications include such things as word processors, database programs, and spreadsheets. In the recording studio, they include digital audio workstations and plug-ins. Also called application software, computer programs, or app for short.
Application Programming Interface (API) – a set of subroutine definitions, protocols, and tools for building computerapplications. APIs are used to provide clearly defined methods of communication between various software components, making it easier to develop a computer application by providing all the needed building blocks. An API may be used for an internet-based system, operating system, database system, or computerhardware. See also web audio API.
All EQ and effects have been added for the specific format (vinyl, cassette, CD, etc.) and the tracks should be in final order with fade outs when used.
Production Master Copy/Clone
A copy is an analog copy and will undergo some degeneration, while a clone is a digital copy and will be identical to the original. This is the version submitted for manufacturing so that the original may to be retained.
archival stability – the ability of a storage medium for audio, video, or film to retain its data in a readable form over time. Archival stability is determined by past performance and testing that simulates long-term storage conditions. Magnetic tape has a relatively low stability, while optical media is considered to have a very long stability. However, how long is anybody's guess.
archive – (1) To save records or documents for an extended period of time, either for historical preservation or for long-term safekeeping. (2) To store audio files on a hard drive or other media when a recording session is completed. (3) See disable.
architectural acoustics – (1) The science of controlling the noise within a building space. (2) The qualities of a building and its materials that determine the sound properties within it.
arithmetic mean – an average that equals the sum of several number or values divided by the number of numbers or values. Sometimes called simply mean or average. See also geometric mean, harmonic mean, and median.
arrange – to adapt a written piece of music for a particular style of performance by voices or instruments. Arranging involves adding different compositional techniques, such as reharmonization, modulation, changing intros or endings, and alternate transitions.
arranger – the person who arranges a written piece of music.
ASCII – American Standard Code for Information Interchange. A standard code for representing computer keyboard characters as binary data, in which alphabetic, numeric, or special characters are represented by 7-bit binary numbers.
A side – Back when singles were released on 45-rpmvinyl records (and 78-rpm singles before that), record labels would designate an A side and a B side, with the A side intended to be played on the radio and hopefully become a hit. Occasionally, a radio disc jockey would flip a record over and play the B side, which sometimes resulted in a B-sided hit. Fairly infrequently, both sides of single would become a hit, a so-called two-sided hit. The media would sometimes write this as “Title A” b/w “Title B,” where b/w meant “backed with”. The B side was sometimes called the flip side, but has come into common usage equivalent to the phrase “on the other hand.” Interestingly, records were originally issued with grooves cut in only one side, until the 1910s when someone realized you could produce a two-sided disc for about the same cost a single-sided disc.
ASIO – Audio Stream Input/Output. A standard for audio drivers that provides high performance and low latency on PC-based computers. Apple's Mac computers use Core Audio
aspect ratio – the width-to-height ratio of an image, especially as applied to film and video. The most common aspect ratios used for movies are 1.85:1 and 2.39:1. The aspect ratio of standard definition television (PAL and NTSC) was 4:3 (1.33:1). For high definition television, it is 16:9 (1.77:1).
assistant recording engineer – someone who helps the recording engineer, with duties that vary by studio, such as placing microphones, setting up and breaking down equipment, and maintaining session logs. Also called assistant engineer, second recording engineer, second engineer, and second.
Association of Musical Electronics Industry (AMEI) – an organization founded in 1996 and headquartered in Tokyo, Japan, to create standards to assure compatibility among electronic musical instruments, especially those using MIDI.
Association of Music Producers (AMP) – a US organization founded in 1997 for the purpose of educating its members, and the production, advertising, and media industries, on all facets of music production, from creation to final use. It is concerned with business matters, such as production guidelines, composerroyalties, music rights agreements, and educational seminars. It also presents the annual AMP Awards.
Association for Recorded Sound Collectors, Inc. (ARSC) – an organization of record collectors, librarian, curators, and researchers, established in 1966 in Silver Spring, Maryland. The purpose of the group is to enhance communications among sound archivists and to encourage research.
asterisk array – an arrangement of several different microphones around a single point so they can be tested by a vocalist or musician. This term was coined by Bruce Kaphan.
ASTM International – an international standards organization that develops and publishes voluntary technical standards for a variety of materials, products, systems, and services. Headquartered in West Conshohocken, PA, it has offices in Canada, Mexico, Belgium, China, and Washington, D.C. It is the oldest of the standards organization having been founded in 1898 as the American Section of the International Association for Testing Materials (IATM). In 1902, it was renamed the American Society for Testing Materials. In 1961, it became the American Society for Testing and Materials. Then in 2001, it changed its name to ASTM International.
ASX – Advanced Stream Redirector. A special type of file which works in conjunction with Windows Media ASF files. The ASF file is the actual media file, containing audio, video, and other media. The ASX file is a metafile (a file which contains data about another file) and is a simple text file containing a reference to an ASF file. ASX files provide Windows Media Player with information about how to present particular media items of the playlist and to start the ASF file streaming.
atmosphere – (1) The collection of gases surrounding the earth. (2) The air or climate in a specific place. (3) The pervading tone or mood of a place. (4) The background noises that are present in a scene or on location, such as wind, water, crowds, and traffic. Also called ambient sound. (5) A unit of pressure defined as 101,325 pascals (Pa), 1,013.25 millibars, 760 torr, 29.92 in Hg, or 14.696 psi. Its symbol is atm. Sometimes called a standard atmosphere. See also atmospheric pressure.
atmospheric pressure – is the force per unit area (pressure) exerted by the weight of air in the atmosphere above it. As elevation increases, there is less overlying atmospheric mass, so atmospheric pressure decreases with increasing elevation. A standard atmosphere is equal to 1 atmosphere (atm), 101,325 pascals (Pa), 101.325 kilopascals, 1,013.25 millibars, 760 torr, 29.92 in Hg, or 14.696 psi. Also called barometric pressure.
ATRAC – Adaptive TRansform Acoustic Coding. A family of proprietary audio file formats developed by Sony. Originally developed as a lossy format for use with the MiniDisc, it has had several improvements over the years, such as ATRAC3, ATRAC3plus, and ATRAC Advanced Lossless. ATRAC files usually have an .aa3 or .oma file extension.
ATSC – (1) Advanced Television Systems Committee. The agency that developed the standards for digital televisiontransmission in the US and several other countries. (2) The standards for digital television transmission developed by the committee. ATSC replaced the analog NTSC television system in the US on June 12, 2009. With the adoption of ATSC 3.0, the original ATSC standard is now referred to a ATSC 1.0.
ATSC 3.0 – the latest standard currently being formulated by the ATSC for digital television. The orginal standard, previously referred to simply as ATSC is now being referred to a ATSC 1.0. (See ATSC, definition #2.) The new standard offers support for newer technologies for over-the-air televison, cable television, satellite television, and internet television. It includes many new improvements for improved television viewing, including HEVC, resolutions of up to 2160p (4K resolution), frame rates of 120 fps, wide color gamut, Dolby AC-4, MPEG-H 3D Audio, and the capabilty for datacasting. In the US, the FCC approved regulations in November 2017 allowing broadcast stations to voluntarily offer ATSC 3.0 services, but they must be offered along with a standard ATSC digital signal. Unlike the transition from analog NTSC to digital ATSC, this transition will not be mandatory.
attack – (1) The beginning of a note as it rises from near silence to its maximum level. Drums have a fast attack, while bowed strings have a slow attack. (2) The first of the four segments of an ADSR envelope. (3) Short for attack time.
au – an audio file format originally introduced by Sun Microsystems and commonly used in Unix and Java systems, as well as on early web pages. It uses a simple 8-bit μ-law algorithm to encode data at a sample rate of 8000 Hz, although other sample rates are sometimes used. Although originally headerless, newer files have a header consisting of six 32-bit words and an optional information section. These files use the extension .au or .snd. Also known as the SPARC audio format or μ-law format.
Audacity – a free open-source digital audio workstation available for Windows, Mac OS X, Linux, and other operating systems, developed by Dominic Mazzoni and Roger Dannenberg at Carnegie Mellon University.
Audinate Pty Ltd. – a company founded in 2006 and headquartered in Ultimo (Sydney), Australia, that develops and markets Dante, a system for transmitting digital audio over (AoE). After Motorola closed its Australian research facility in 2003, a team of researchers took their research to the National Information and Communication Technology Australia (NICTA) in Sydney, Australia, where with the help of government funding, they began to develop Dante. In 2006, Audinate was founded to bring Dante to the market.
audiobook – the recording of the reading of a book, typically a novel, but non-fiction and technical books are also available. Originally these were sold on cassette, but later became available on CD. Sometimes called a talking book or book on tape.
audio coding format – a method for storing or transmitting digitalaudio files, such as MP3, AAC, Vorbis, and FLAC. The method by which audio is compressed and decompressed is the codec. For example, LAME is the most common codec for encoding MP3 files, but there are a number of others that can be used. Audio encoded in a particular audio coding format is normally encapsulated within a container format known as an audio file format, which usually contains the encoded audio and metadata that provides such information as to the codec, bit rates, and other information needed to decompress the data, as well as title, artist, and other information. The main exception is the MP3 file, which does not use a container file. The method of adding metadata such as ID3 tags is a work around that takes advantage of the fact that MP3 players ignore such data. An audio coding specification is a document that details the technical details of the coding format. If the document has been written and approved by a standards organization, it is usually called an audio coding standard. Audio coding format is sometimes called audio compression format.
audio compression – see compression. Note: Audio compression is often used to refer to both audio compression and data compression, which can lead to some confusion.
audio compression manager (ACM) – a mostly obsolete Microsoft program for managing audio codecs on Windows platforms. Files encoded with this process use the extension .acm, and are usually stored in a wrapper such as WAV or AVI.
Audio Engineering Society (AES) – a professional organization established in 1948 for engineers, scientists, other individuals with an interest or involvement in audio technology and the professional audio industry.
Audion – a vacuum tube used to amplify weak electric signals invented by Lee De Forest in 1906. The Audion was the first triode and consisted of a partially evacuated glass tube with three electrodes: a heated filament, a grid, and a plate. It was the first widely used tube used for amplification. De Forest thought that a small amount of gas should be present in the glass tube, unlike later vacuum tubes. However, this was not the case as it caused erratic performance. Within a few years, the Audion was superseded by improved versions with higher vacuums, and eventually by the developement of the transistor.
audio over IP (AoIP) – a method for streaming audio over great distances using an IP network. IP stands for Internet Protocol, a set of communication protocols used on the internet and similar computer networks. AoIP is used by broadcasters and others to provide high-quality audio feeds using the Internet. It is also known as audio contribution over IP (ACIP), referring to contributions made by field reporters and remote events. For transmitting audio locally, such as within a music venue or within a building, audio over Ethernet (AoE) is the more likely choice to avoid the problems associated with AoIP. Also called an audio network.
audiophile – a person who is enthusiastic about high quality sound reproduction.
audio post production for video (APPV) – any audio work done after completing the shooting of a film or video, such as replacing dialog, adding sound effects, and adding music. Post production is the process of preparing the final mix of the soundtrack that will be synchronized with the video, which includes television, movies, and commercials. The typical order for this operantions is: (a) dialog editing, (b) automatic dialog replacement, (c) sound design, (d) Foley, (e) music composition and editing, and (f) mixing. Also called audio post production, post production, or post for short.
audio restoration (AR) – the process of removing pops, clicks, hum, hiss, and other noises from an audio file. Although it was originally developed to clean up vintage recordings, it is often applied to current audio files. See also denoiser.
audio spectrum – the audiblefrequencies of human hearing, which generally is considered to be between 20 Hz and 20,000 Hz (20 kHz), which is about 10 octaves. There is considerable variation in this range among individuals, especially for the higher frequencies, and there is usually a gradual decline in the ability to hear higher frequencies with age. Also called the audio bandwidth, aural bandwith, audio frequencies, or hearing range. The audio spectrum is sometimes broken down into three main ranges: bass (20 Hz to 350 Hz), midrange (350 Hz to 5 kHz), and high end (5 kHz to 20 kHZ). These ranges are sometimes further devided into deep bass (20 Hz to 40 Hz), low bass (40 Hz to 80 Hz), mid bass (80 Hz to 160 Hz), upper bass (160 to 350 Hz), lower midrange (350 Hz to 600 Hz), middle midrange (600 to 1200 Hz), upper midrange (1.2 kHz to 2.4 kHz), presence range (sometimes called the middle highs)(2.4 kHz to 5 kHz), high end (5 kHz to 10 kHz), and extreme high end (10 kHz to 20 kHz). The exact nomenclature and frequencies differ with various sources, but are generally in the ranges specified.
AudioSuite™ – a proprietary plug-in format developed by Avid for Pro Tools. AudioSuite plug-ins can process and modify audio files offline and can be configured to either create an entirely new audio file or to alter the original audio file. See also RTAS.
Audio-Technica Corporation – Kabushiki-gaisha Odio Tekunika. A company founded in 1962 in Tokyo, Japan, that designs and manufactures professional microphones, wireless microphones, headphones, magnetic phonographic cartridges, and other audio equipment. Audio-Technica introduced its first microphones in 1978 and its first wireless microphones in 1986. Sometime abbreviated as A-T.
Audiotonix – an audio equipment company formed in 2014 with the merger of DiGiCo, Allen & Heath, and Calrec. In 2017, Auditonix was sold to a private equity firm in Europe. Later in 2017, Audiotonix acquired Solid State Logic (SSL).
Audio Video Bridging (AVB) – a set of technical standards developed by the IEEE Time-Sensitive Networking Task Group (formerly the Audio Video Bridging Task Group) of the IEEE 802.1 standards committee, that provides specifications to allow time-synchronized low-latency audio and video streaming services through IEEE 802 networks. See also Time-Sensitive Networking.
audiovisual (AV or A/V) – (1) Works that have both a sound and a visual component. (2) The production or use of works that have both a sound and a visual component. (3) The equipment used to create and present works with both a sound and a visual component, such as film, television, and slide-tape presentations. Sometimes called audio/video.
audition – (1) A test performance by a performer or musician to demonstrate suitability for a specific role, a position in a band or group, a recording contract, or other performance-related situations. (2) To monitor or to listen to a track or an audio file to assess its quality and other characteristics. (3) To listen to audio equipment to make a purchase decision.
auditory hemispheric dominance (AHD) – having a dominant ear in hearing. Just as most people are right-handed, most people have a dominant right ear. Although this is perfectly normal, recording engineers need to be aware of potential issues: (1) a tendency when mixing to favor panning to one particular side, (2) imagelocalization may be more difficult for some people with a dominant left ear due to a small amount of latency in that ear.
Audix Microphones – a designer and manufacturer of microphones founded in 1984 and headquartered in Wilsonville Oregon. Audix makes a full line of professional microphones, but they may be best known for their microphones designed for use with drums.
augmented chord – a chord with two stacked major thirdintervals, which is equivalent to a major triad with a sharpedfifth. In other words, the top note is raised by half a step. A major triad, such as C-E-G, contains a major third (C-E) and a minor third (E-G), with C-G being the interval of a fifth. The augmented triad sharpens the fifth (becoming an augmented fifth), resulting in C-E-G♯. An augmented fourth is a tritone. Augmented chords are represented by adding either “aug” or “+” such as Caug or C+. Also called a augmented triad.
augmented reality (AR) – the live view on a screen or other display of a physical, real-world environment enhanced by overlaying computer-generated images, sounds, graphics, GPS information, or other data. By contrast, virtual reality (VR) replaces the real world with a totally artificial environment.
augmented unison – the interval produced by raising a unison by one semitone. In other words, it is the interval between notes occupying the same position on the musical staff or notes having the same letter where one note has been raised by a semitone, such as B♭ and B or C and C♯. It is the enharmonic equivalent of a semitone or minor second. Also called augmented prime.
aural – pertaining to the ear or the sense of hearing.
Auro-3D® – an immersive audio format developed in 2005 by Auro Technologies and Barco. It is an expansion of the 5.1surround sound format and adds overhead ceiling spekers (sometimes called the “Voice of God”), which creates a spatial sound field by adding a height layer around the audience. The height layer presents both localized sounds and height reflections that complement the existing sounds in the lower surround layer.
Auro Technologies – a company founded in 2010 in Mol, Belgium, by Wilfried and Guy Van Baelen and Alfred Schefenacker to promote and advance the Auro-3D immersive audio format. The Van Baelens also own the Galaxy recording studio.
Australian Broadcasting Corporation (ABC) – the state-owned national public broadcasting network in Australia, offering educational and cultural programming through television, radio, online, and mobile services throughout Australia, and in other countries through the Australia Network and Radio Australia. It was founded in 1929 as the Australian Broadcasting Company. In 1932, it became the Australian Broadcasting Commission. Upon passage of the Australian Broadcasting Corporation Act 1983, it took its current name.
autolocate – a function that sends a tape or disc to a pre-programmed position upon the press of a button.
Automated Processes, Inc. (API) – a company located in Jessup, MD, that manufactures high-end equipment for recording studios, such as preamplifiers, equalizers, and mixing consoles. They manufacture and own the trademark for the API Lunchbox®, a line of 500 series modules. The company was founded in 1968 by Saul Walker and Lou Lindauer. In 1973 API introduced the first computerized mixing console featuring an automation system for fader level control. One year later this system was expanded to include automation with recall of equalization, sends, pans, and faders. In 1985, API was purchased by Paul Wolff, who owned the company until 1999, when the assets of the company were sold to ATI (Audio Toys, Inc.), who manufactures sound reinforcement equipment including the Paragon mixing console.
automatic dialog replacement (ADR) – the process of adding dialog in sync with the moviesoundtrack in a sound studio after the movie has been completed. Also called post synchronization (primarily in UK and Europe) or informally dubbing. See also dub.
automatic double tracking (ADT) – a special effect that simulates double-tracking, two voices or instruments playing together, created by combining a signal with a duplicate signal that is slightly detuned and/or delayed by 15 to 35 milliseconds. ADT is similar to chorusing, but with a shorter delay. Sometimes called artificial double tracking.
automatic gain control (AGC) – a circuit that adjusts the incoming signal of an audio device to maintain a constant level in the output signal. Also called automatic volume control (AVC).
automatic mixer – a special type of mixer that automatically turns microphonechannels on and off as needed without user intervention. An automatic mixer is controlled by a gain-sharing algorithm, which controls the level of each individual microphone, produces a mix with a constant gain from all mics, maintains a constant acoustic gain equal to the needed acoustic gain (NAG), and optimizes the feedback stability margin (FSM). Also called an automatic microphone mixer, automatic mic mixer, microphone automixer, or automixer.
automation curve – the graphical representation of the changes in automation data for a given audio or MIDI track. The curve consists of lines connected by a series of dots at each point where the parameter changes. These dots are called break point, edit points, or anchors. In some DAWs an automation curve is called an automation envelope or automation line.
automation envelope – the name used in some DAWs for the graphical representation of the changes in automation data for a given audio or MIDI track. An automation envelope may be superimposed on top of the audio or MIDI track or it may be displayed in a separate lane below the track, called an automation lane. See also clip envelope.
auto power down (APD) – a feature of some equipment that automatically reduces the power drain after a prescribed amount of time. Also called automatic power down, automatic shut down, or auto shut down.
auto punch – the process that allows a recording engineer to automatically overdub a specific section of a digitalrecording, either by highlighting that section or by entering precise start and stop information. See also punch.
autoranging – the automatic switching of the ranges on a device so that the lowest range not exceeding full-scale is used or displayed. Autoranging is sometimes used on multirange meters and input gain controls.
auto save – a feature of some DAWs and other software that automatically saves the open files at specified intervals. Sometimes spelled autosave.
autotune – to correct an out-of-tune vocal or instrumental performance. See also Auto-Tune.
Auto-Tune® – a pitch correctionprocessor developed by Antares Audio Technologies that measures the pitch of a vocal or instrumental audio signal and adjusts the pitch to the nearest semitone. Auto-Tune is available as a plug-in for us professional recording studios as well as a stand-alone unit for processing live performances. Although it was originally created to correct off-key notes, it has also come into use as an effect to distort the human voice when pitch corrections are made extremely fast, which has become known as the “Cher effect” or the “T-Pain effect.”
auxiliary master – a control on the auxiliary sendbus used to adjust the overall level being sent to that bus. Also called aux master.
auxiliary return – the signal path used to return signals from processors, effects devices, or plug-ins. The aux send is used to feed the device and the aux return is used to return the signal from the device. Also called aux return, effects return, auxiliary loop, or aux loop. See auxiliary bus.
Avid Technology, Inc. – a company that provides solutions for capturing, creating, editing, and distributing digital media. Avid is the current owner and supplier of Pro Tools.
AVnu Alliance – a consortium of professional, automotive, and consumer electronics companies working together to establish and certify the interoperability of open Audio Video Bridging (AVB) and Time Sensitive Networking (TSN) standards. The Alliance has a program to certify AVB and TSN products that meet their criteria. The AVnu logo may be used by manufacturers on products that are certified.
AV receiver (AVR) – a consumer electronics device for use with televisions and home theater systems, used to amplify sound from a variety of audio sources,such as DVD players, Blu-ray Disc players, VCRs, and video game consoles, as well as to route audio/video signals from these sources to the television or other displays. Many AVRs also include an AM/FMtuner. Sometimes called an audio receiver.
axe – slang term for a musical instrument, especially a guitar. Sometimes spelled ax.
axial mode – one of the three room modes in which resonance in a room is caused by sound reflecting between two parallel surfaces, such as front to back, side to side, or floor to ceiling. The other two modes are tangential mode and oblique mode.
axis – an imaginary line that runs straight through an object or figure. In the recording studio, this is most often applied to a microphone in the sense of an sound source being on-axis or off-axis. Plural is axes.
axis angle – the angle between the axes of two microphones used in stereo microphone techniques. The axis angle can be adjusted over a small range to change the relationship between the physical sound source positions in front of the microphones and their perceived positions in the stereo image, which is called the stereo recording angle, and should not be confused with the axis angle. Also called opening angle, mutual angle, offset angle, and receiving angle. Compare with acceptance angle, which applies to just one microphone.
Note: We believe this is the largest dictionary (glossary) of terms specific to usage within the recording industry that is currently available on the internet, with more than 8,000 entries, nearly 600 illustrations, and dozens of tables. Some of the terms have different or additional meanings in other situations, especially within the electronic, automotive, scientific, and computer industries. Of necessity there are obvious overlaps into other fields such as music, electronics, and computers, but such excursions are limited to information deemed pertinent to the knowledge required to operate and/or participate effectively in the workings of a recording studio. Also included are terms related to sound reinforcement (live performances) including wireless microphone technology because a working knowledge of that terminology is necessary for recording at live performance venues. Because recording studios also record audio for video and motion pictures (films), some terminology from those fields is included. Some scientific terms are included because they help explain studio terminology. For example, electromagnetism explains how microphones, loudspeakers, and guitar pickups work. Knowledge of radio waves and the radio frequency spectrum is needed to explain wireless devices. Any trademarks or trade names mentioned belong to their respective owners. The information contained in this dictionary is believed to be accurate at the time of publication. This information is subject to change without notice. The information was obtained from and cross-checked with a variety of sources that are believed to be reliable. However, Los Senderos Studio, LLC does not guarantee the accuracy or completeness of the information contained herein. Please contact us to report any errors, omissions, discrepancies, or broken links. Los Senderos Studio shall not be responsible for any consequences or damages arising out of the use of this information. Nothing in this glossary should be interpreted as legal advice. For a glossary providing information on legal and business matters for musicians, we suggest you consult Musicians Business Dictionary.
A note on alphabetical order: The terms in this glossary are alphabetical without regard to spaces and punctuation. For example, AM Radio follows amplitude. While this may seem to be at odds with other conventions, it eliminates confusion with words such as pickup, which is sometimes written as pick up or pick-up. The entries on the number page (0-9) are listed in increasing value within each digit. For example, all of the entries beginning with 1 are listed before those starting with 2. For Greek letters (α-ω), the entries are in Greek alphabetical order.