Pro Audio Reference


Pro Audio Reference (G)


G The symbol for conductance.

gack Live audio. Popular slang: 1. To pretend to play a musical instrument, especially guitar. 2. An excessive or disordered collection of miscellaneous gear. [Thanks Bink!]

gadulka Musical Instrument. A Bulgarian bowed stringed instrument.

gagaku Music. A type of Japanese music.

gaida (also gajda) Musical Instrument. A form of Balkan bagpipe with the bag made from the whole skin of a goat or lamb, sometimes with the wool still left on so it looks like the player is squeezing a lamb under their arm. [Thanks, GD!]

gain The amount of amplification (voltage, current or power) of an audio signal, usually express in units of dB (i.e., the ratio of the output level to the input level). For example, amplifying a voltage signal by a factor of two is stated as a voltage gain increase of 6 dB. [Historical Usage Note: originally the terms 'gain/loss' were restricted to power use only, and 'amplify/attenuate' were used for voltage and current — although I can find no historical explanation for this arbitrary split, and no existing standards can be found that continue to make such a distinction. It is interesting to add, that conformity with such a narrow definition of 'amplification' says that the original manufacturers misnamed their products: they should have been called a 'gainifier' -- not an 'amplifier.' According to the true believers a 'power amplifier' is a contradiction since you cannot 'amplify' power, only 'gainify' it. 'Power gainifier' is the correct term, according to them.]

gain bandwidth product See GBW.

gain-before-feedback Acoustics. The amount of gain that can be achieved in a sound system before feedback or ringing occurs. [Vear]

gain riding Recording term. The act of constantly monitoring and adjusting as necessary the gain of a recording process to prevent overloading the medium.

gain-sharing Microphone Automixers. A shortened form meaning a gain-sharing algorithm. Using a gain-sharing algorithm, each individual microphone input channel is attenuated by an amount, in dB, equal to the difference, in dB, between that channel’s level and the level of the sum of all channels. A gain-sharing automatic mixing algorithm provides several benefits. First, the algorithm produces a mix that has a constant gain from all inputs to the output. When the gain of the system is constant, an operator can create a public address system in which the acoustic gain is constant, and equal to the Needed Acoustic Gain (NAG). In such a system, the Feedback Stability Margin (FSM) may be maximized, and remains constant regardless of the number of microphones. Also, in a system where background noise is detected evenly by all microphones, a gain-sharing algorithm produces a constant level of background noise at the mix output regardless of the number of microphones or their input signal levels. In other words, the gain-sharing algorithm produces no gating, pumping, or breathing effects in the reinforced background noise of the public address system. A gain-sharing algorithm also reduces the comb filtering effect produced by two or more microphones detecting the same acoustic signal. Using Rane’s proprietary (patent pending) method for distributing a gain-sharing automixer across multiple devices, the gain-sharing algorithm and all of its benefits are preserved even though the mixing and inputs are shared among various physical devices.

gain stage Any of several points in an electrical circuit where gain is taken (applied).

gain suppression See suppression.

GAL® (generic array logic) Registered trademark of Lattice Semiconductor for their invention of EEPROM-based low-power programmable logic devices.

Galois field (aka finite field) (after French mathematician Évariste Galois) Mathematics. A field with a finite number of elements.

galvanic Electronics. Of or relating to direct-current electricity, especially when produced chemically. [AHD]

galvanic action Electronics. Noise currents due to the junction or thermal potentials resulting from a combination of different metals. This current can be a part of the disturbing current passing through the conductors or shield of the signal cable. [IEEE]

galvanic isolation Electronics. Prevention of electrical current from passing between sections. Common examples are transformers and optocouplers. Any system with ground common is NOT galvanically isolated.

gang, ganged, ganging To couple two or more controls (analog or digital) mechanically (or electronically) so that operating one automatically operates the other, usually applied to potentiometers (pots). The volume control in a traditional two-channel hi-fi system is an example of a ganged control, where it is desired to change the gain of two channels by the same amount, and now in home theater and DVD-audio applications, used to change 6 or more channels simultaneously.

Gantt chart A chart that depicts progress in relation to time, often used in planning and tracking a project. [After Henry Laurence Gantt (1861-1919), American engineer.]

Gaohu Musical Instrument. Chinese bowed-string instrument.

gap Recording. The space between opposite poles of a recording or playback head in a magnetic tape recorder.

gap detection threshold Hearing. Measure of the shortest interruption of a signal that can be detected by a listener. [Lass & Woodford]

garmon Musical Instrument. A type of Russian accordion.

gas tube A protection device in which a sufficient voltage across two electrodes causes a gas to ionize, creating a low impedance path for the discharge of dangerous voltages.

gas-discharge tube A protection device designed to carry current during gas breakdown. The gas-discharge tube is commonly used as a protective device, preventing high voltages from damaging sensitive equipment.

gate See noise gate.

gated or gated-on Teleconferencing. Term referring to microphone inputs on an automatic mic mixer that turn off (close) after speech stops. Contrast with last-on.

gateway Networks. A network point that acts as an entrance to another network, similar to a router.

gauge Wire & Cable. A measure of the diameter of wire. See AWG for more details.

Gaumont Chronophone See: Chronophone.

gauss Abbr. Gs The centimeter-gram-second unit of magnetic flux density, equal to one Maxwell (one line of flux) per square centimeter. [After Gauss, Karl Friedrich.] [AHD]

Gauss, Karl Friedrich (1777-1855). German mathematician and astronomer known for his contributions to algebra, differential geometry, probability theory, and number theory. [AHD]

Gaussian distribution Statistics. Same as normal distribution. A theoretical frequency distribution for a set of variable data, usually represented by a bell-shaped curve symmetrical about the mean. [AHD]

GBIC (gigabit interface connector) See Ethernet.

GBW (gain bandwidth or gain bandwidth product ) (aka unity gain bandwidth) Op Amps. Alternate specification for the unity gain frequency of the device. An op amp's frequency vs. gain response rolls off at a 20 dB/decade (6 dB/octave) rate. Because of this the unity gain bandwidth specification (the frequency where the open loop gain is one or unity) also equals the gain bandwidth product. For example, say an op amp has a unity gain frequency equal to 10 MHz. This can be restated as a GBW of 1 x 10 MHz. Since the slope is 20 dB/decade, then this device will have 20 dB of open loop gain at 1 MHz, 40 dB gain at 100 kHz, 60 dB gain at 10 kHz, and so on.

G clef See: treble clef.

GE (gigabit Ethernet) See Ethernet.

geeeezzzeeee! Favorite expression of George Sheppard, CEO, Rane Corporation.

Generation X The tenth generation of Americans since 1776. [From Roman numeral X meaning 10.] See Beat Generation.

generator Electricity. A machine that converts mechanical power into electrical power. [AHD]

Gentlemen of the Road Stopover Festivals From their website: "A Stopover is a celebration of a real place, with

real people. It's a bridge between the culture of a music festival and actual culture as lived by real-life people. We

bring the music, the stage, the flags and the fans; everything else belongs to the town. Their energy and

enthusiasm, their civic pride...their favorite local beer. We've found it to be a beautiful thing — maybe the most

beautiful thing that we do."

geological piano See: rock harmonicon.

geometric progression A sequence, such as the numbers 1, 3, 9, 27, 81, in which each term is multiplied by the same factor in order to obtain the following term. Also called geometric sequence. [AHD]

geomungo Musical Instrument. Korean plucked-string musical instrument.

Gerzon, Michael (1945-1996) British mathematician considered one of the true geniuses of the twentieth century. Made many pro audio inventions the most famous of which is Ambisonics and the theory behind the tetrahedron microphone. See Robert Charles Alexander's biography Michael Gerzon: Beyond Psychoacoustics for details of his too short but fascinating life.

getter A small amount of material added to a chemical or metallurgical process to absorb impurities. In vacuum tubes it is a small cup or holder, containing a bit of a metal that reacts with oxygen strongly and absorbs it. In most modern glass tubes, the getter metal is barium, which oxidizes very easily forming white barium oxide. This oxidization removes any oxygen remaining after vacuumization.

Gibbs phenomenon Signal Processing. The ringing and overshoot that can occur when constructing a waveform by adding together harmonics and abruptly stopping the harmonic series after a finite number of terms. [Greenebaum]

gibi Symbol Gi New term standardized by the IEC as Amendment 2 to IEC 60027-2 Letter Symbols to be Used in Electrical Technology to signify binary multiples of 1,073,741,824 (i.e., 2E30). Meant to distinguish between exact binary and decimal quantities, i.e., 1,073,741,824 verses 1,000,000,000. For example, it is now 16 gibibits, abbreviated 16 Gib, not 16 gigabits or 16 Gb.

Gidget Nickname for girl-midget from the 1959 movie of the same name, based on the book by Frederick Kohner about his surfer daughter Kathy. [This for all you Jeopardy! fans.]

gig Slang. A job, especially a booking for musicians. [AHD]

giga- A prefix signifying one billion (10E9), abbreviated G.

gigabyte Popular term meaning a billion bytes but should be gibibyte meaning 2E30 bytes. See gibi.

gigahertz Abbr. GHz One billion cycles per second.

GIGO (garbage in garbage out) Popular acronym used by programmers to indicate that incorrect information sent to a system generally results in incorrect information received from it.

gigue See jig.

glass Popular jargon referring to glass fiber optic interconnection, or fiber optics in general.

glass harmonic or glass harmonica Music. A musical instrument comprising separate glasses, playing the rims, or a long tapered cylinder rotating and played by hand. First mentioned in the early 1740s and later improved by Benjamin Franklin in 1761.

Glastonbury Festival Considered the world's largest greenfield festival, held at the Worthy Farm near Pilton, Somerset, England, which is about six miles from the town of Glastonbury. See also Glastonbury Festival.

glide See portamento.

glissando Music. A rapid slide through a series of consecutive tones in a scale-like passage. [AHD] [Like way too many rock guitar solos.]

glitch A perturbation of the pulse waveform of relatively short duration and of uncertain origin. [IEEE] 1. A minor malfunction, mishap, or technical problem; a snag: a computer glitch; a navigational glitch; a glitch in the negotiations. 2. A false or spurious electronic signal caused by a brief, unwanted surge of electric power. [AHD] Word History: Although glitch seems a word that people would always have found useful, it is first recorded in English in 1962 in the writing of John Glenn: "Another term we adopted to describe some of our problems was 'glitch.' " Glenn then gives the technical sense of the word the astronauts had adopted: "Literally, a glitch is a spike or change in voltage in an electrical current." It is easy to see why the astronauts, who were engaged in a highly technical endeavor, might have generalized a term from electronics to cover other technical problems. Since then glitch has passed beyond technical use and now covers a wide variety of malfunctions and mishaps. [AHD] [In digital audio glitches sound bad. ]

glitch edit DJ. A popular remixing effect. See Jason Scott Alexander's "Fractal Tendencies" published in Remix magazine for how-to tips.

glockenspiel A percussion instrument with a series of metal bars tuned to the chromatic scale and played with two light hammers. [AHD]

glottis Sound. 1. The opening between the vocal cords at the upper part of the larynx. 2. The vocal apparatus of the larynx. [AHD]

GMT (Greenwich Mean Time) See: universal time.

GND (ground) Electronics. Common abbreviation seen on electronic and electrical schematic diagrams.

gobble pipe Saxophone. [Decharne]

goblet drum (aka Chalice drum, Darbuka or Doumbek) Musical Instrument. A wine glass shaped hand drum indigenous to the Middle East.

gobo (Might be a shorten form for "go between" but I cannot find any verification.) 1. Cinematography & Photography. A portable screen used to shield a camera lens from light or a microphone from noise. 2. Acoustics & Recording. A sound absorbent screen used to isolate instruments during multitrack recording, minimizing microphone crosstalk.

Goddard, Robert Hutchings (1882-1945) See Roswell, NM.

Golden Ratio or Golden Rectangle See phi.

Goldmark, Peter Carl (1906-1977) Hungarian-born, naturalized American citizen, engineer credited (along with his many more significant inventions) with inventing the LP (long playing) record in 1948 while working at Columbia Records.

Golliwogs The original name of the band that evolved into Creedence Clearwater Revival.

googol The number 10 raised to the power 100 (10100), written out as the numeral 1 followed by 100 zeros. [Coined at the age of nine by Milton Sirotta, nephew of Edward Kasner (1878-1955), American mathematician.] [AHD]

googolplex The number 10 raised to the power googol, written out as the numeral 1 followed by 10100 zeros. [AHD]

GOTS (government off-the-shelf ) Government procurement term. Most often referencing software but general use is found. Compare with COTS, MOTS and NOTS.

Gottwood  Since 2010 a boutique electronic and music festival held in the Welsh forest on the Isle of Anglesey, Wales.

Governors Ball Music festival held on Randall's Island, NYC, featuring ferry ride to festival as well as an art show, face painting and lawn games..

GPI (general purpose interface)

GPIB (general purpose interface bus) See IEEE-488.

gradient microphone See pressure-gradient microphone and ribbon microphone.

Grado, Joseph (1924-2015) Italian immigrant who founded Grado Labs, famous for high-end phono cartridges and headphones.

graffiti Plural of graffito. Usage Note: The word graffiti is a plural noun in Italian. In English graffiti is far more common than the singular form graffito and is mainly used as a singular noun in much the same way data is. When the reference is to a particular inscription (as in There was a bold graffiti on the wall), the form graffito would be etymologically correct but might strike some readers as pedantic outside an archaeological context. There is no substitute for the singular use of graffiti when the word is used as a mass noun to refer to inscriptions in general or to the related social phenomenon. The sentence Graffiti is a major problem for the Transit Authority Police cannot be reworded Graffito is ... (since graffito can refer only to a particular inscription) or Graffiti are ... (which suggests that the police problem involves only the physical marks and not the larger issue of vandalism). In such contexts, the use of graffiti as a singular is justified by both utility and widespread precedent. [AHD]

graffito A drawing or inscription made on a wall or other surface, usually so as to be seen by the public. Often used in the plural (see above). [AHD]

gralla Muscial Instrument. A type of Catalan oboe.

gram Abbr. g or gm. or gr. A metric unit of mass equal to one thousandth (10-3) of a kilogram. [AHD]

gramophone British term referring to any sound reproducing machine using disc records, as disc records were popularized in the UK by the Gramophone Company. Invented by Emil Berliner.

Grammy Shorten form of gramophone, name of the Grammy Awards given by The Recording Academy.

granulation noise An audible distortion resulting from quantization error.

graphene A one-atom-thick sheet of pure carbon which won the 2010 Nobel Prize for Physics; among many different things it is experimentally producing silicon-less transistors.

graphic equalizer A multi-band variable equalizer using front panel mechanical slide controls as the amplitude adjustable elements. Named for the positions of the sliders "graphing" the resulting frequency response of the equalizer. Only found on active designs. Center frequency and bandwidth are fixed for each band.

graphic-level recorder A device for recording signal level in decibels versus time. The level in decibels versus angle can be recorded also for directivity patterns. [Everest]

Grashof, Nusselt and Prandtl numbers Thermodynamics. All are found in the study of natural convection as occurs, for example, from heat sinks in audio power amplifiers: Grashof (Gr), is the ratio of buoyant force to viscous force; Nusselt (Nu) is the coefficient of heat transfer; and Prandtl (Pr) is the ratio of the molecular diffusion coefficients of momentum in terms of heat, i.e., a property of air. And for those who love a good formula, this is the correlation for natural convection from a flat plate: Nu = 0.59 (Gr Pr)0.25 [Kordyban]

graticule A scale for measurement of quantities displayed on the cathode-ray tube of an oscilloscope. [IEEE]

grating, reflection phase An acoustical diffraction grating to produce diffusion of sound. [Everest]

Gray code A sequence of binary values where only one bit is allowed to change between successive values. Generally "quieter" (producing less audible interference) than straight binary coding for execution of commands in audio systems.

Gray, Elisha (1835-1901) American electrical engineer who invented the Musical Telegraph after developing the first telephone, more or less simultaneously with Alexander Graham Bell.

gray noise See noise color.

Gray, Stephen (1666-1736) British chemist who is credited with the discovery of electrical conduction and insulation.

Green Book Nickname for the Philips and Sony's ECMA-130 standard document that defines the format for CD-I (compact disc-interactive) discs; available only to licensees. Compare with Red Book and Yellow Book.

green noise See noise color.

Greenwich time See: universal time.

greenockite A yellow to brown or red mineral, CdS, the only ore of cadmium. [After Charles Murray Cathcart, Second Earl Greenock (1783-1859), British soldier.]

grid Electron tubes (valves). The current controlling element in a tube located between the plate and the cathode. It is equivalent to the base in a transistor. A triode tube consists of a plate, cathode and grid, which are directly analogous to the collector, emitter and base of a transistor. See audion.

grill Cooking. To broil on a gridiron. [AHD]

grille 1. A grating of metal, wood, or another material used as a screen, divider, barrier, or decorative element, as in a window or on the front end of an automotive vehicle. 2. An opening covered with a grating. [AHD]

grille cloth Loudspeakers. A tough acoustically transparent cloth (or metal) put over the front of a loudspeaker to protect the speaker from damage.

groan box Accordion. [Decharne]

ground Electronics. The common reference point for electrical circuits; the return path; the point of zero potential.

grounding: correct, proper & best See AES48, Steve Macatee's Considerations in Grounding and Shielding, the RaneNote Sound System Interconnection; Tony Waldron and Keith Armstrong, "Bonding Cable Shields at Both Ends to Reduce Noise," EMC Compliance Journal, May 2002, and Jim Brown's Power and Grounding for Audio and Audio/Video Systems: A White Paper for the Real World.

ground lift switch 1. Found on the rear of many pro audio products, used to separate (lift) the signal ground and the chassis ground connection. 2. Common three-pin to two-pin AC plug adapter used to reduce ground loops. [NOTE: This is unsafe and illegal. DO NOT USE.] For discussion See Steve Macatee's Considerations in Grounding and Shielding and the RaneNote Sound System Interconnection.

ground loop 1. Electronics. Within a single circuit, or an audio system, the condition resulting from multiple ground paths of different lengths and impedances producing voltage drops between paths or units. A voltage difference developed between separate grounding paths due to unequal impedance such that two "ground points" actually measure distinct and different voltage potentials relative to the power supply ground reference point. See Steve Macatee's Considerations in Grounding and Shielding and the RaneNote Sound System Interconnection 2. Aviation. The tendency of a tailwheel aircraft (vs. tricycle gear) to pivot around its vertical axis during runway operations in the presence of a high crosswind. [Thanks DK.]

groups (aka subgroup or submix) A combination of two or more signal channels gathered together and treated as a set that can be varied in overall level from a single control or set of controls. Mixing consoles often provide a group function mode, where the level of any group of incoming singles may be adjusted by a single slide fader, which is designated as the group fader. Likewise in certain signal processing equipment with splitting and routing capabilities, you will have the ability to group together, or assign, outputs allowing control of the overall level by a single external controller.

group delay Same as envelope delay [technically the time interval required for the crest of a group of waves to travel through a 2-port network -IEEE.] The rate of change of phase shift with respect to frequency. Mathematically, the first derivative of phase verses frequency. The rate of change is just a measure of the slope of the phase shift verses linear (not log) frequency plot. If this plot is a straight line, it is said to have a "constant" (i.e., not changing) phase shift, or a "linear phase" (or "phase linear" -European) characteristic. Hence, constant group delay, or linear group delay, describes circuits or systems exhibiting constant delay for all frequencies, i.e., all frequencies experience the same delay. Note that pure signal delay causes a phase shift proportional to frequency, and is said to be "linear phase," or "phase linear." In acoustics, such a system is commonly referred to as a "minimum phase" system. For a circuit example, see Bessel crossover. Also see Siegfried Linkwitz's Group delay and transient response, and the RaneNote Linkwitz-Riley Crossovers: A Primer.

GR plug See connectors: banana plug.

grunge (aka Seattle sound) Music. A style of rock music that incorporates elements of punk rock and heavy metal, popularized in the early 1990s and often marked by lyrics exhibiting nihilism, dissatisfaction, or apathy. [AHD] The defining sound of the 1990s; click Nirvana for example.

GUI (graphical user interface) A generic name for any computer interface that substitutes graphics (like buttons, arrows, switches, sliders, etc.) for characters; usually operated by a mouse or trackball. First mass use was Apple's Macintosh™ computers, but is now dominated by Microsoft's Windows™ programs.

gumbo ya-ya New Orleans slang for everybody talking at once.

guqin See qin.

guitar A musical instrument having a large flat-backed sound box, a long fretted neck, and usually six strings, played by strumming or plucking. [AHD] Also see: electric guitar.

guitarron Musical Instrument. A six string bass instrument most popular among Mariachi groups, but found throughout Argentina, Chile, Mexico and Puerto Rico.

gut scraper Violinist. [Decharne]

Gutta-percha Wire & Cable. A type of insulation used for early wire cables.

gyrator filters Term used to describe a class of active filters using gyrator networks. Gyrator is the name given for RC networks that mimic inductors. A gyrator is a form of artificial inductor where an RC filter synthesizes inductive characteristics. Used to replace real inductors in filter design. See the RaneNote Constant-Q Graphic Equalizers.

AES - Audio Engineering Society