Dictionary of Audio Terminology - V
V - The symbol for voltage.
VA - voltampere.
Vactec - 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. 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.
valence - 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.
values, standard component values - Resistors and capacitors.
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 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.]
vanity radio - Term coined by Errol Smith, co-founder of INA (International Nanocasting Alliance).
vaporware - Refers to either hardware or software that exist only in the minds of the marketeers.
Variable-D® - 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) A variable transformer used to vary AC voltages.
varistor (variable resistor) A two-terminal semiconductor device having a voltage-dependent nonlinear resistance.
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.
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."
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 - 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.
vegetable diode - See LEVD.
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 - 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 - 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.
Venn diagrams - 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.
vertical interval time code - See time code.
vestibular system - The part of the human ear that senses translational and rotational acceleration of the head, and its orientation with respect to gravity.
VHS (video home system) - Trademark for the most popular video tape format, invented by JVC in 1976.
vias - (aka feed-through hole) A pad with a plated-through hole connecting one layer to another.
vibration - Any time-varying oscillation about a state of equilibrium.
vibrato - A tremulous or pulsating effect produced in an instrumental or vocal tone by minute and rapid variations in pitch.
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.
VI meter - volume indicator
vinyl Common name for any phonograph record. 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.
virgule - 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.
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.
VITC - vertical interval time code
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.
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
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 - (1) Musical sound produced by vibration of the human vocal cords and resonated within the throat and head cavities. (2) The quality or condition of a person's singing: a baritone in excellent voice. (3) A singer: a choir of excellent voices. (4) 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. 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."
voice coil - See loudspeaker.
voiced bilabial fricative - A speech sound. See fricative.
voiceless dental fricative - A speech sound. See fricative.
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. 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.
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.]
Volta, Count Alessandro - (b. 1745-1827) Italian physicist who invented the battery (1800). The volt is named in his honor.
voltage - Electromotive force or potential difference, usually expressed in volts.
voltage follower - See buffer amplifier.
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 - (b. 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 - (1) The amplitude or loudness of a sound. (2) A control, as on a radio, for adjusting amplitude or loudness.
VOM - (volt-ohm-milliammeter) A portable test instrument for measuring voltage (volts), resistance (ohms) and current (amperes). Also see VTVM.
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.
VPN - (virtual private network) A secure Internet connection using encryption and tunneling protocols to create a safe connection, or tunnel, to a private network.
VPR Alliance - (Vertical Powered Rack Alliance) API Audio's program of standardization 500 Series module manufacturers.
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.
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. 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).
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.
VXCO - (voltage-controlled crystal oscillator A crystal-based oscillator whose center frequency can be varied with an applied voltage.
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