Glossary – V

  Vacuum Tube – A diode, a glass tube with the gases removed, through which electrical current can flow. In audio, vacuum tubes are used in amplifiers, oscillators, and other analog devices.   Vamp – A part of a song or chord progression that is repeated, usually at the end of the song, and usually the chorus or part of the chorus.   Vamp and Fade – A method of ending the recording of a song where the music has a repeating part and the engineer reduces volume until the music fades out.   Vari-Speed – A control on a tape machine that changes the play speed.   Variable-D – A trademarked, patented technology of ElectroVoice in its microphone designs to vary the proximity effect in its microphones. Variable-D places several ports along the microphone body, each of which has a reduced level of sensitivity to higher frequencies the further they are placed from the microphone’s diaphragm.   VCA – Shorthand for “Voltage Controlled Amplifier,” an amp whose gain is affected by an external voltage fed to it.   VCA Automation – A system of mix automation in some mixing consoles in which sound levels or other functions are altered through the use of voltage controlled amplifiers.   VCA Group – Several VCA faders that are fed control voltages from a group master slide. A feature in higher-end mixing boards that enables the engineer to control groupings of independent signals by a single fader that uses VCA to adjust the voltage sent to each channel.   VCO – See “Voltage Controlled Oscillator.”   Velocity Message – In synthesizers and keyboard controllers, a MIDI message that transmits data on how hard the key was struck. Velocity messages can be used to transmit volume information, as well as triggering different samples on a multi-sampled instrument patch.   Velocity Microphone – See “Pressure-Gradient Microphone.”   Velocity Sensitive – (Also called “Touch Sensitive“) A feature on a MIDI instrument such as a keyboard that transmits a MIDI velocity message depending on how hard the key is struck.   Vibrato – A smooth and repeated changing of the pitch up and down from the regular musical pitch, often done by singers or performed by string and wind players.   Virtual Instrument – (Also called Software Instrument) One of a number of software-based synthesizers, samplers or sound samples that are stored and accessed via computer and performed by an external MIDI controller, rather than in a standalone synthesizer or module. Because of the wide versatility available from these instruments, a growing number of composers and electronic musicians are working with virtual instruments that can be stored in hard drives, rather than purchasing stacks of keyboards and modules.   Vocal Booth – A room in the recording studio that is used for recording vocals in isolation. This practice prevents bleed-through of the sounds of other instruments into the vocal microphone, and also reduces natural ambience and reverberation in the vocal recording.   Vocoder – An audio processing device effects device or plug-in that analyzes the characteristics of an audio signal and uses them to affect another synthesized signal. Primarily developed for the purpose of producing synthesized voice effects from human speech, a vocoder creates the characteristic robotic vocal sound or the “human synthesizer” effect that makes it sound like the synth is speaking or singing words.   Voice – 1) Besides the obvious definition of the sound humans make from their mouths…in synthesizers, a voice refers to one of a number of sounds/pitches that may be played at the same time. “Monophonic” means only one voice plays at a time, while “polyphonic” means multiple voices can sound at once. (See also “Polyphonic”, “Monophonic.”) 2) In some synthesizers, like Yamaha, “voice” may also refer to a specific sound patch available on the synth.   Voice Over – The recording of vocal announcements or narration over a bed of music in video, film or commercials.   Volatile Memory – Computer memory whose data will will be lost when the computer is turned off. RAM (Random Access Memory) is the most common form of volatile memory.   Voltage – The difference in electrical force or pressure (“potential”) between two objects, causing a flow of electric current between them.   Voltage Controlled Oscillator (VCO) — An oscillator whose frequencies are modified by voltage input. Most commonly found in synthesizers.   Voltage Controlled Amplifier (VCA) – An amplifier whose gain level is affected by an external voltage being sent to it. VCAs are commonly used in synthesizers, signal processors, and as a means of automation for some mixing consoles.   Voltage Controlled Filter – A filter (especially a low-pass filter) that will change its cutoff frequency according to a control voltage fed to its control input.   Volume – A common, non-technical term that either refers to sound pressure level (which we hear as loudness), or to audio voltage level.   Volume Unit (VU) – A unit to measure perceived loudness changes in audio. The unit is basically the decibel change of the average level as read by a VU Meter. (See also “VU Meter.”)   Vox – A Latin word meaning “voice,” often used as an abbreviation for track logs in the studio.   VU Meter – A meter that reads audio voltage levels in or out of a piece of equipment and is designed to match the ear’s response to sudden changes in level.