Vap
A common file extension specifying an indexed file format. Typically encountered as FILENAME.VAP

Vbase
A type of indexed files containing raw audio data plus additional format, control, and annotation information. These files permit you to group related audio segments, then access those segments by specifying an index number.

VBR
Variable BitRate Encoding attempts to address this shortcoming. It dynamically allocates extra bits during complex sections of the audio track and uses fewer when it can get away with it during simpler sections of the audio. The end result is an MP3 file with a consistent quality level throughout the entire track. The disadvantage is that, it is impossible to predict the size of the finnished MP3 file. As a result, some MP3 players have difficulty with VBR-encoded files because they can't determine the play time of the track.

VCA
AVoltage-Controlled Amplifier is an audio signal amplifier whose output is controlled by voltage (instead of a potentiometer). VCAs can be used to alter the amplitude of a signal output from a VCO.

VCD
AVideo CD is a compact disc which stores video and audio compressed using MPEG-1 file format technology. Movies are generally compressed to around 352x240 pixels (NTSC) resulting in about 1 GB of data, which spans over two CDs. While they aren't common in the USA, VCDs are more common in other countries where many popular electronics companies sell dedicated VCD players. DVD technology surpasses the quality of VCD technology, mostly due to the increased storage capacity of DVD media.

VCF
AVoltage-Controlled Filter is a filter whose cutoff frequency and resonant frequency is adjusted using a control voltage. VCFs are used to filter the audio signals generated by VCOs in an analog synthesizer in order to create more interesting and textured sounds.

VCO
AVoltage-Controlled Oscillator is an analog circuit that generates a electrical waveform, such as a Sine, Saw or Square wave where the pitch is determined by a control voltage. VCOs are used by older analog synthesizers to generate the base sounds which are then altered by VCAs and VCFs.

Velocity
A type of MIDI data (range 1 to 127) usually used to indicate how quickly a key was pushed down (attack velocity) or allowed to rise (release velocity). Note: A note-on message with a velocity value of 0 is equivalent to a note-off message.

velocity curve
A map that translates incoming velocity values into other velocities in order to alter the feel or response of a keyboard or tone module.

velocity sensitivity
A type of touch sensitivity in which the keyboard measures how fast each key is descending. Compare with pressure sensitivity.

Vibrato
A periodic change in frequency, often controlled by an LFO, with a periodicity of less than 20 Hz; also see tremolo.

VITC
Short for "Vertically Integrated Time Code" - synchronization signal for video interfacing ; it is blended into the video signal. In contrast to LTC, the synchronization signal can also be read in a static image.

Virtual
Existing only in software.

VOC
A file extension specifying the Creative Labs Sound Blaster audio format. Typically encountered as FILENAME.VOC.

Vocoder
an audio effect that produces "robotic" sounding results when processing vocal input. It uses an algorithm called ring modulation to produce the effect. Examples can be found in some disco and modern music, such as the Beastie Boys' "Intergalactic". 

Voice
a) An element of synthesizer circuitry capable of producing a note. The polyphonic capability of a synthesizer is defined by how many voices it has. > polyphony.
b) In Yamaha synthesizers, a patch (sound).

voice channel
A signal path containing (at a minimum) an oscillator and VCA or their digital equivalent, and capable of producing a note. On a typical synthesizer, two or more voice channels, each with its own waveform and parameter settings, can be combined to form a single note.

voice stealing
A process in which a synthesizer that is being required to play more notes than it has available voices switches off some currently sounding voices (typically those that have been sounding longest or are at the lowest amplitude) in order to assign them to play new notes.

Vox
A file extension specifying a generic telephony audio format. Typically encountered as FILENAME.VOX

VQF (TwinVQ)
The VQF format is the much-shortened name for Transformdomain Weighted Interleave Vector Quantization format, also called TwinVQ. It was developed by Nippon Telegraph and Telephone (NTT) and produces audio files with better compression and better sound quality than MP3. However, compared to MP3, VQF requires substantially greater time for the encoding process. Support for VQF has waned as of late, but MPEG-4 audio will incorporate the technology.

VST Plug-In
A program that uses Steinberg's VST technology to obtain digital audio samples which are then manipulated by applying reverb, compression or some other type of audio signal effect. The output signal may be rendered off-line or generated in real-time while the plug-in's host program performs playback. See Plug-In for more details.