Pro Audio Reference


Pro Audio Reference (V)


V The symbol for voltage.

VA (voltampere) See voltampere.

Vactec Electronic Components. The name of a company acquired by EG&G, famous for their optoelectronics family and especially their photocouplers and LDRs which featured prominently in early compressors and limiters.

vacuum tube An electron tube where virtually all the air has been removed (creating a vacuum), thus permitting electrons to move freely, with low interaction with any remaining air molecules. [AHD] The first tube was a two-element diode, invented and patented by Ambrose Fleming in 1904, based on the Edison effect. Three years later, in 1907, Lee de Forest developed the first triode (known as the Audion) by adding a grid between the cathode (emitter) and the anode (collector), thus creating the first amplifier since a change of voltage at the grid produced a corresponding (but greater) change of voltage at the anode.

valance Theater. A part of the stage draperies, usually ornamental, which hangs in front of the main curtain.

valence Chemistry. The combining capacity of an atom or radical determined by the number of electrons that it will lose, add, or share when it reacts with other atoms. [AHD]

valiha Musical Instrument. A Madagascar zither-type stringed instrument.

values, standard component values Resistors and capacitors. See: Standard Component Values and color-code.

valve British term for vacuum tube, popularized because the first tube was known as the Fleming valve named for its inventor Ambrose Fleming.

Van de Graaff generator An electrostatic generator using a moving belt and a hollow metal ball. Biggest in the world is at the Boston Museum of Science, built in the 1930s by Dr. Van de Graaff, it uses two 15 feet diameter aluminum balls and can generate 2 million volts. Hit the link for photos and more in depth details.

van den Hul Phonographs. Dutch company said to make the best phono cartridges ever produced.

van der Waals equation An equation of state that relates the pressure, volume, and absolute temperature of a gas taking into account the finite size of molecules, and their intermolecular attraction, having the form RT = (P + av-2)(v - b), where R is the gas constant, T is the absolute temperature, P is the pressure, v is the volume, and a and b are constants. [After Johannes Diderik van der Waals (1837-1923), Dutch physicist.] [AHD]

vanity radio Podcasting. Term coined by Errol Smith, cofounder of INA (International Nanocasting Alliance).

Vans Warped Tour A touring music festival that travels all over the USA and Canada featuring primarily punk and alternative acts.

Van Vliet, Don Musician. Birth name of musician who performed as Captain Beefheart.

vaporware Refers to either hardware or software that exist only in the minds of the marketeers.

var (volt-ampere reactive) Electric Power Circuits. The unit of reactive power in the International System of Units (SI). The var is the reactive power at the two points of entry of a single-phase, two-wire circuit when the product of the root-mean-square value in amperes of the sinusoidal current by the root-mean-square value in volts of the sinusoidal voltage and by the sine of the angular phase difference by which the voltage leads the current is equal to one. [IEEE]

varactor A two-terminal semiconductor device in which the electrical characteristic of primary interest is a voltage-dependent capacitance. [IEEE]

Variable-D® Microphones. Registered copyright of Electro-Voice for their broadcast dynamic microphone design that claims to virtually eliminate the proximity effect resulting in a uniform low-frequency response, up-close or at a distance.

variable-Q graphic equalizer See proportional-Q graphic equalizer.

variac (variable AC) Electronics. A variable transformer used to vary AC voltages.

varicap Electronics. A diode used as a variable capacitor.

varistor (variable resistor) Electronic Component. A two-terminal semiconductor device having a voltage-dependent nonlinear resistance. [IEEE]

VAS (virtual auditory space) Localization. A binaural reproduction technique that allows headphone sound to appear to be coming from any direction.

VCA (voltage-controlled amplifier or voltage-controlled attenuator) An electronic circuit comprised of three terminals: input, output and control. The output voltage is a function of the input voltage and the control port. The gain of the stage is determined by the control signal, which is usually a DC voltage, but could be a current signal or even a digital code. Usually found as the main element in dynamic controllers, such as compressors, expanders, limiters, and gates. See THAT Corporation's VCA History.

VCR (videocassette recorder) A magnetic tape recorder for recording and playback of video programs. "The first VCR was made in 1956 and was the size of a piano." (Snapple Real Fact #180)

VCXO (voltage-controlled crystal oscillator) A crystal-based oscillator whose frequency is controllable by an external voltage.

V-DOSCA trademark of L-Acoustics, the "V" refers to the V-shaped acoustic lens configuration employed for their mid and high frequency line array sections. The "DOSC" is a French acronym for "Diffuser d'Onde Sonore Cylindrique"— in English this translates to "cylindrical wave generator," an apt description of the performance of their line arrays.

VDT (video display terminal) Computer monitor, or data terminal with a monitor.

vector Mathematics. A quantity, such as velocity, completely specified by a magnitude and a direction.

vector diagram A drawing that shows the direction and magnitude of a quantity by a vector arrow. See the RaneNote Linkwitz-Riley Crossovers: A Primer.

veena Musical Instrument. A stringed instrument of India that has a long, fretted fingerboard with resonating gourds at each end. [AHD]

vegetable diode See LEVD.

vegetable orchestra See Viennese Vegetable Orchestra.

Velcro® (velour + crochet) Named by combining the first syllable of two French words: velour (velvet) and crochet (hook) by inventor George de Mestral, Swiss Engineer, in 1941. He got the idea while removing sticky cockleburs from his dog. He examined one under a microscope and discovered they were covered with thousands of tiny hooks. He then went on to see if he could duplicate the effect to create a fastener.

velocimeter Acoustics. A device for measuring the speed of sound in a liquid, usually water. Typically done using two transducers arranged as a transmitting and receiving pair, located a fixed distance apart. A short acoustic pulse is transmitted between the two and the travel time measured.

velocity Synthesizers & MIDI. How fast a key is depressed. Used to control loudness or other parameters.

velocity microphone See pressure gradient microphone and ribbon microphone.

velocity of sound Acoustics. The international standard is 331.45 m/s (1087.42 ft/s) at 0 °C (32 °F) and 0% humidity. For the effects of temperature and humidity see: Bohn, Dennis A. "Environmental Effects on the Speed of Sound," J. Audio Eng. Soc., Vol. 36, No. 4, April 1988, pp. 223-231.

vernier calipers An instrument having a fixed and a movable arm on a graduated stock, used for measuring the diameters of logs and similar objects. [AHD]

Venn diagrams Mathematics. A logic diagramming system invented by the British logician, John Venn (1834-1923) that uses overlapping circles to represent mathematical sets and their relationships.

vented loudspeaker See bass reflex.

venu Musical Instrument. A South India bamboo flute and is one of the oldest musical instruments of India.

vertical interval time code See time code.

vestibular system Hearing. The part of the human ear that senses translational and rotational acceleration of the head, and its orientation with respect to gravity.

V Festival Music festival held yearly in the U.K. during August, sponsored by the Virgin Group, hence the "V".

VHF See frequency bands.

VHS (video home system) Trademark for the most popular video tape format, invented by JVC in 1976.

vias (aka feed-through hole) Printed Circuit Boards. A pad with a plated-through hole connecting one layer to another.

vibraphone Musical Instrument. A percussion instrument similar to a marimba but having metal bars and rotating disks in the resonators to produce a vibrato. Also called vibraharp. [AHD]

vibration Any time-varying oscillation about a state of equilibrium.

vibration acceleration Acoustics. The rate of change of speed and direction of a vibration, in a specified direction. The frequency bandwidth must be identified. Unit: meter per second squared. Unit symbol: m/s2 [Harris]

vibration meter An apparatus for the measurement of displacement, velocity, or acceleration of a vibrating body. [Harris]

vibration transducer A device which converts shock or vibratory motion into an electrical (or optical, or mechanical) signal that is proportional to a parameter of the experienced motion. [Harris]

vibrato A tremulous or pulsating effect produced in an instrumental or vocal tone by minute and rapid variations in pitch. [AHD] [Think: frequency modulation as in fast pitch changes.]

vibroacoustics Fluids. The study of coupled fluid and structural waves in fluid-loaded structures. [Morfey]

vibroacoustics therapy The practice of using audio sound waves to create vibrations that are applied to the human body. Said to create physiological and psychological change through vibrations.

Victor Shorten form for The Victor Talking Machine Company (1901-1929). The company was named "The Victor" in honor of legal victories by founder Eldrige R. Johnson and Emile Berliner over Zonophone and others concerning their rights to patents on and distribution of their products.

Victrola The copyrighted name given to the line of internal horn phonographs made by the Victor Talking Machine Company.

videoconferencing Video and audio communication held by two or more people over a distance using a codec at either end and linked by digital networks (T-1, ISDN, etc.). Contrast with teleconferencing.

viella Musical Instrument. French name for hurdy-gurdy.

Viennese Vegetable Orchestra Music. Innovative (to say the least!) Austrian ensemble that plays nine different instruments carved and peeled from ordinary garden vegetables, played by three men and six women.

vihuela Musical Instrument. A Spanish guitar-like stringed instrument. The modern Mexican vihuela is played in mariachi groups.

Villari effect See: magnetostriction.

Villchur, Edgar M. (1917-2011) American inventor, entrepreneur, educator, audio pioneer, who cofounded Acoustic Research in 1952, with Henry Kloss. Best known for inventing the acoustic-suspension loudspeaker. [Ref: "Problems of Bass Reproduction in Loudspeakers," Jour. Audio Engineering Society, vol. 5, no. 3, July 1957, pp. 122-126, and "Commercial Acoustic Suspension Speaker, " AUDIO, July, 1955.)

VI meter (volume indicator) See: VU meter

vinyl Common name for LP phonograph records. Hit the link to read its fascinating history. Also rock vinyl history. And here for DJ vinyl history right from the very beginning of records - fascinating.

viol Musical Instrument. Any of a family of stringed instruments, chiefly of the 16th and 17th centuries, having a fretted fingerboard, usually six strings, and a flat back and played with a curved bow. [AHD]

viola Musical Instrument. 1. A stringed instrument of the violin family, slightly larger than a violin, tuned a fifth lower, and having a deeper, more sonorous tone. 2. An organ stop usually of eight-foot or four-foot pitch yielding string like tones. [AHD]

violet noise See noise color.

violin Musical Instrument. A stringed instrument played with a bow, having four strings tuned at intervals of a fifth, an unfretted fingerboard, and a shallower body than the viol and capable of great flexibility in range, tone, and dynamics. [AHD] Extremely old, the first four-string violin was build by Andrea Amati in 1555.

virginal Musical Instrument. A small, legless rectangular harpsichord popular in the 16th and 17th centuries. Believed so called, because commonly used by young ladies. [AHD]

virgule Printing. A diagonal mark ( / ) used especially to separate alternatives, as in and/or, to represent the word per, as in miles/hour, and to indicate the ends of verse lines printed continuously, as in Old King Cole/Was a merry old soul. [AHD]

virtual auditory space See: VAS.

Virtual Studio Technology See: VST.

virus A self-replicating program released into a computer system for mischievous reasons. Once triggered by some preprogrammed event (often time or date related), the results vary from humorous or annoying messages, to the destruction of data or whole operating systems. Bad bad.

viscous damping Physics. The energy dissipation that occurs when a part of a system or an element is resisted by a force whose magnitude is proportional to the velocity of the element but is in the opposite direction from that of the velocity. [Harris]

visual microphone "When sound hits an object, it causes small vibrations of the object's surface. We show how, using only high-speed video of the object, we can extract those minute vibrations and partially recover the sound that produced them, allowing us to turn everyday objects—a glass of water, a potted plant, a box of tissues, or a bag of chips--into visual microphones." [from the MIT Abstract description. Fascinating; hit the link and check it out.]

VITC (vertical interval time code) See time code.

Vitruvius Pollio, Marcus (circa 1st century BC) Very early Roman architect who worked with amphitheater acoustics and developed an analogy between sound in air and waves on water.

Vivid Sydney From website: "Vivid Sydney is a unique annual event of light, music and ideas, featuring many of the world's most important creative industry forums, a mesmerizing free public exhibition of outdoor lighting sculptures and installations, a cutting-edge contemporary music program and the spectacular illumination of Sydney's iconic architecture including the sails of Sydney Opera House."

VJ (video jockey) Term coined by the MTV generation for jocks that present music videos on television or nightclubs or parties. [Or for us old farts: V-J Day, the date of Allied victory over Japan, World War II, August 15, 1945.] Compare with DJ and KJ.

Vladimir Baranoff Rossine (1888-1944) Russian artist and inventor whose Optophonic Piano was an early color-organ.

VLAN (Virtual Local Area Network) A network of devices (computers) that look like they are connected to the same network but, in fact, they are physically located on different LANs.

VLSI (very-large-scale integration) Refers to the number of logic gates in an integrated circuit. By today's standards, a VLSI device could contain up to one million gates.

VO (voiceover) See: voiceover.

vocal cords See: vocal folds.

vocal folds "Fold of tissue in the larynx whose vibrations creates the periodic sound present in the voiced sounds of speech." [Bregman] Either of two pairs of bands or folds of mucous membrane in the throat that project into the larynx. The lower pair vibrate when pulled together and when air is passed up from the lungs, thereby producing vocal sounds. The upper, thicker pair are not involved in voice production. [AHD]

Voca People Music. An international vocal theater performing group consisting of vocal sounds, a cappella singing and beatboxing.

vocoder (voice coder) 1. Invented by Homer Dudley (no fooling) in 1936 at Bell Labs, and called a "phase vocoder." It was an electronic device for analyzing and synthesizing, or generating artificial speech. Homer Dudley was the first person to recognized that the basic information rate of speech is low and that if you broke it down into its basic components, these could be transmitted over a quite narrow bandwidth, and then reconstructed at the receiving end. Thus was born the speech synthesizer. The vocoder principal is based on determining the formants, or vowel sounds, of the speech signal, along with its fundamental frequency and any noise components such as plosive sounds (a speech sound produced by complete closure of the oral passage and subsequent release accompanied by a burst of air, as in the sound (p) in pit, or (d) in dog), hisses, or buzzes. Typically this is done by using two sets of filter banks — one for analysis and one for synthesis -- and an "excitation analysis" block. The analysis filter bank is much like those used in real-time analyzers. The audio is presented to a bank of parallel connected bandpass filters, whose output levels are converted into DC voltage levels proportional to the signal passing through each bandpass filter. This captures the formant information. The excitation analysis block determines and codes the fundamental frequency and noise attributes. Reconstruction occurs by using the encoded DC levels, mixed with the excitation block output, to gate each output bandpass filter, which are then summed together to recreate a facsimile of the original speech signal. Early pictures and audio samples (from Prof. Edward A. Lee, UC Berkeley). 2. Once vocoder basics were established, they found new uses in electronic music applications. The MI (musical instrument) vocoder uses speech input to modulate another music instrument signal so that it "talks." Use of vocoders peaked in the '70s after being popularized by such notables as Wendy Carlos, Alan Parsons and Stevie Wonder. This vocoder version has two inputs, one for the vocal microphone and one for another instrument. Talking or singing into the microphone modulates or superimposes vocal characteristics onto the other instrument. Compare with talk box.

VoFi (voice-over-IP-over-Wi-Fi) The technology that allows normal telephone calls to be made over the Internet.

voice Music. a. Musical sound produced by vibration of the human vocal cords and resonated within the throat and head cavities. b. The quality or condition of a person's singing: a baritone in excellent voice. c. A singer: a choir of excellent voices. d. One of the individual vocal or instrumental parts or strands in a composition: a fugue for four voices; string voices carrying the melody. Also called voice part. [AHD] Synthesizers. Playing two or more patches at the same time.

voice box Popular term for the human larynx: "The part of the respiratory tract between the pharynx and the trachea, having walls of cartilage and muscle and containing the vocal cords enveloped in folds of mucous membrane." [AHD].

voice coil See loudspeaker.

voiced Linguistics To pronounce with vibration of the vocal cords. Music a. To provide (a composition) with voice parts. b. To regulate the tone of (the pipes of an organ, for example). 4. To provide the voice for (a cartoon character or show, for example): The animated series was voiced by famous actors. [AHD]

voiced bilabial fricative A speech sound. See fricative and link.

voiceless dental fricative A speech sound. See fricative and link.

voice lift Sound Reinforcement. Increasing the loudness level (and intelligibility) of a voice signal. Particularly in classroom situations, where it is generally better to outfit the teacher with a wireless headset than to have them speak without amplification.

Voice of the Theater® Loudspeaker. Famous motion picture theater sound system by Altec, designated the A-4, it replaced the Shearer Horn as the dominate theater loudspeaker system in the '40s.

voiceover 1. The voice of an unseen narrator, or of an onscreen character not seen speaking, in a movie or a television broadcast. 2. A film or videotape recording narrated by a voiceover. [AHD] Common examples of voiceovers include cartoon characters, documentary videos of all types, computer software tutorials, audio books, and automated telephone messages.

VoIP (voice over Internet protocol) The technology that allows you to transmit voice conversations (i.e., the ability to make telephone calls) and send faxes over a data network using the Internet Protocol. Think, voice email.

volatile Refers to a memory device that loses any data it contains when power is removed from the device. Examples would include static and dynamic RAMs.

Volkman, John E. (1905-1980) American engineer who, in the '30s, was the first to use EQ in motion picture theater sound systems.

volt Abbr. E, also V. The International System unit of electric potential and electromotive force, equal to the difference of electric potential between two points on a conducting wire carrying a constant current of one ampere when the power dissipated between the points is one watt. [After Count Alessandro Volta.] [AHD]

Volta, Count Alessandro (1745-1827) Italian physicist who invented the battery (1800). The volt is named in his honor. [AHD]

voltage Electromotive force or potential difference, usually expressed in volts. [AHD]

voltage follower See buffer amplifier.

Voltaire Pen name of François Marie Arouet. 1694-1778. French philosopher and writer whose works epitomize the Age of Enlightenment, often attacking injustice and intolerance. He wrote Candide (1759) and the Philosophical Dictionary (1764). [AHD]

voltampere (VA) The product of rms voltage and rms current in an electronic circuit. It is the unit of apparent power in the International System of Units (SI).

Volterra, Vito(1860 - 1940) Italian mathematician and physicist, whose original work on partial differential equations and the equation for cylindrical waves is most relevant to pro audio research.

Volumax CBS trademark for a broadcast limiter invented by Emil Torick in the '50s to replace the transmitter watch engineer.

volume Sound 1. The amplitude or loudness of a sound. 2. A control, as on a radio, for adjusting amplitude or loudness. [AHD]

VOM (volt-ohm-milliammeter) A portable test instrument for measuring voltage (volts), resistance (ohms) and current (amperes). Also see VTVM.

voodoo boilers A kit of drums. [Decharne]

vote "The instrument and symbol of a freeman's power to make a fool of himself and a wreck of his country." — Ambrose Bierce.

VOTT See: Voice of the Theater.

vowels "The voiced sounds of speech that are combined with consonants to form syllables. Examples are 'ah', 'oo', and 'ee'." [Bregman]

VOX (voice operated exchange) Also called voice operated relay, originally a tape recorder feature where speech starts the recording process and silence stops it. However it is not restricted to tape recorders, for instance, cellular phones use VOX to save battery life, and teleconferencing systems use it to determine the number of active mics. See NOM.

VPN (virtual private network) A secure Internet connection using encryption and tunneling protocols to create a safe connection, or tunnel, to a private network. [Intel glossary]

VPR Alliance (Vertical Powered Rack Alliance) API Audio's program of standardization for 500 Series module manufacturers.

VR (virtual reality)

VRAS (variable room acoustic system) An EAE system developed by Meyer and LCS Audio.

VRML (virtual reality modeling language) A method for describing interactive 3D scenes delivered across the internet. In short, VRML adds 3D data to the Web. At on time heavily supported by Silicon Graphics (SGI) workstations, competing with Sun's Java loaded workstations.

vroom The loud, roaring noise of an engine operating at high speed. [AHD]

VSL (Video-SL) Serato's software add-on to its Scratch Live system that allows DJs to manipulate video along with music using vinyl emulation control records.

VST (Virtual Studio Technology™) A trademark of Steinberg for their interface standard for integrating software plug-ins with audio editors.

VSWR (voltage standing-wave ratio) Electronics. A waveguide mode: it is the ratio of the magnitude of the transverse electric field in a plane of maximum strength to the magnitude at the equivalent point in an adjacent plane of minimum filed strength. (IEEE) For pro audio it shows up in qualifying coax cables, where it is a measure of return loss. It is a measure of the reflected energy from a transmitted signal, and is affected by such factors as poor connectors, connections, cable defects and abuse. [Technically it should be SWR as there is only one SWR, not one for voltage and another for current.]

VTVM (vacuum tube voltmeter) Antiquated term for a test instrument measuring voltage, resistance and current, constructed using vacuum tubes, which required plugging it into an AC voltage source, thus not portable. Characterized by having very high input impedance (compared to the standard VOM) that allowed more precise measurements. Replaced today by solid-state DMM (digital multimeter).

Vulcan Harp Fictional musical instrument popularized by Mr. Spock in the Star Trek TV series.

vulcanize To improve the strength, resiliency, and freedom from stickiness and odor of (rubber, for example) by combining with sulfur or other additives in the presence of heat and pressure. [AHD] After the Roman mythology god of fire and metalworking, Vulcan.

Vulcanized fiber See fishpaper.

vulgar fractions Chiefly British term for common fractions, although sometimes used to mean improper fractions (those with a larger numerator than denominator). (Word History: Vulgar is an example of pejoration, the process by which a word develops negative meanings over time. The ancestor of vulgar, the Latin word vulgris (from vulgus, "the common people"), meant "of or belonging to the common people, everyday," as well as "belonging to or associated with the lower orders." Vulgris also meant "ordinary," "common (of vocabulary, for example)," and "shared by all.") [AHD]

VU meter (volume unit) The term volume unit (originally called VI or volume indicator; now archaic usage) was adopted to refer to a special meter whose response closely related to the perceived loudness of the audio signal. It is a voltmeter with standardized dB calibration for measuring audio signal levels, and with attack and overshoot (needle ballistics) optimized for broadcast and sound recording. Jointly developed by Bell Labs, CBS and NBC, and put into use in May, 1939, VU meter characteristics are defined by ANSI specification "Volume Measurements of Electrical Speech and Program waves, " C16.5-1942 (which is know incorporated into IEC 60268-17). 0 VU is defined to be a level of +4 dBu for an applied sine wave. The VU meter has relatively slow response. It is driven from a full-wave averaging circuit defined to reach 99% full-scale deflection in 300 ms and overshoot not less than 1% and not more than 1.5%. Since a VU meter is optimized for perceived loudness it is not a good indicator of peak performance. Contrast with PPM.

vuvuzela (aka lepatata) Musical Instrument. A trumpet-shaped horn indigenous to South Africa; popular at soccer games. For those who find the sound offensive see: How To Silence Vuvuzela Horns.

VXCO (voltage-controlled crystal oscillator A crystal-based oscillator whose center frequency can be varied with an applied voltage.

AES - Audio Engineering Society