Daftar Istilah Akustik

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stereo image - A panoramic acoustical image derived from two sources. The effect of being able to identify the location of different sounds from different places anywhere between sources.

stereo microphone - A microphone that has two (or more) elements in it to derive a stereo image of the source. It has two (different) output signals as well.
stereo return - A dual channel line input on a mixer with one set of controls for both inputs. Usually has limited control capability (EQ, etc.) It's designed to take the output of an effects device (where the effect is returned in to the mixer).

Stereopsis - The most important mechanism for assessing depth in human
vision. First enunciated in 1838 by Sir Charles Wheatstone (who also
invented the "Wheatstone bridge" in electricity), stereopsis depends on the slight differences in the two pictures projected on the retinas. (See also parallax.)

stiffness - Stiffness characterizes the ability of a material to resist bending.

structure-borne sound - Sound for which a significant portion of the transmission path from source to receiver takes place in a solid structure rather than through a liquid or gas.

stud - An upright 2 x 4 or 2 x 6 wall framing member.

sub - a mixer subgroup.

sub-bottom profiling - Determining the sedimentary structure of the ocean floor by utilizing sound waves.
subgroup - A fader on larger mixers that receives the level of all the input channels that are assigned to it, controls the level of the combined signal, and then passes that signal on to the master level controls. Often subgroups have their own independent outputs to allow for multi-track recording. Features on a subgroup vary depending on the mixer. The concept is to allow multiple microphones that are related (like all the drum mics or all the male background vocals) to have one overall control each.
subharmonic - Sinusoidal quantity having a frequency that is an integral submultiple of the fundamental.
submaster - Term for subgroup. Submasters are usually distinguished from subgroups in that there will only be a left and right (subgroups usually have 4 to 8 controls).
submixer - A mixer that's used to mix several sources together and then output the signal to another mixer. This allows more inputs to be mixed than the master mixer can handle (or for the submix to be done at a location different than where the main mixer is).
subs - Short for subwoofer or subgroups.
subsonic - In aerodynamics, of or pertaining to, or dealing with speeds less than acoustic velocity as in subsonic aerodynamics.
subsonic flow - Flow of a fluid, as air over an airfoil, at speeds less than acoustic velocity.
Aerodynamic problems of subsonic flow are treated with the assumption that air acts as an incompressible fluid.
subwoofer - A speaker that's designed to reproduce very low frequencies (only), typically below 50Hz. Usually employs the use of very large cone drivers. The frequency range and size of the subwoofers is relative to the rest of the speaker system they are designed to accompany. If a main speaker has a frequency response down to only 80Hz, the subwoofer used may cover 50Hz to 80Hz. If the main system goes down to 50Hz, the subs may operate from 30Hz to 50Hz.

summed mono - A mono signal that's derived by mixing the left and right stereo signals together. The mono signal is then whatever the sum of the two signals. If the two signals contain information that's opposite each other, it will cancel (leaving no signal). Any variation of the two signals will result in some frequencies partially or totally canceling while others will be enhanced. This is in contrast to discrete mono where the signal is always and only one signal.
supercardioid microphone - A microphone that's more directional than a cardioid microphone. Typical specifications are: coverage angle=115-degrees, maximum rejection=126-degrees (2-points).
superposition - Many sound waves may traverse the same point in space, the air molecules responding to the vector sum of the demands of the different waves.
supersonic - Of or pertaining to, or dealing with, speeds greater than the acoustic velocity. Compare with ultrasonic.

supersonic compressor - A compressor in which a supersonic velocity is imparted to the fluid relative to the rotor blades, the stator blades, or to both the rotor and stator blades, producing oblique shock waves over the blades to obtain a high pressure rise.
supersonic diffuser - A diffuser designed to reduce the velocity and increase the pressure of fluid moving at supersonic velocities.
supersonic flow - In aerodynamics, flow of a fluid over a body at speeds greater than the acoustic velocity and in which the shock waves start at the surface of the body. Compare hypersonic flow.
supersonic nozzle - A converging-diverging nozzle designed to accelerate a fluid to supersonic speed.

supersonics - Specifically, the study of aerodynamics of supersonic speeds.
surround sound - A speaker system that has speakers both in front and behind the listener. Can mean a variety of channel separation and speaker placement systems. Most commonly, involves left and right channels placed to either side of the front "screen" each with different signal information. A center channel will be placed in the middle of the front screen but may be either a discrete or summed mono channel (used primarily for speech). Typically in a theater, the side and back speakers are all one discrete channel. In current home theaters, the back speakers are usually a mix of the left and right channels at lover levels. The subwoofers are usually a summed mono signal.
sweepable EQ - An equalizing control or filter that has a variable center frequency. This allows the user to cut or boost a range of frequencies centered around a frequency that's determined by a separate control rather than only the range of frequencies pre-determined by the device.

synthesizer - An electronic musical instrument.
Synthetic listening - The ability of a listener to perceptually isolate individual elements of a complex sound or sequence, such as frequency components in a complex sound or individual events in rapid sequences. In synthetic listening the tendency is to perceive sound complexes or temporal sequences in a global fashion. [1]

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t1 (initial time-delay gap or ITDG) - In concert hall acoustics, the time interval, measured in milliseconds, between the arrival at a seat in the hall of the direct sound from a source on stage to the arrival of the first significant reflection. It corresponds with the subjective impression of "intimacy." [2]

T60 - See RT60.

Talkback - On some mixers, a microphone or microphone input that allows the operator to talk to people via the main, group, or auxiliary outputs. Much like a normal mic channel input, but only contains routing switches (usually only momentary) and a volume (gain) control.
tangential mode - A room mode produced by reflections off four of the six surfaces of the room.

tape return - The signal coming from a tape player usually to a mixing console.

target strength - A measure of the percentage of the acoustic energy hitting the target that is reflected back to the transducer.
TDS - Abbreviation for Time Delay Spectrometry.

TEF - A computer based platform for measuring audio devices and acoustic environments, manufactured by Techron and more recently Goldline under license from the Jet Propulsion Laboratory, Pasadena, California. See also Time Delay Spectrometry. [3]

Tempo - The speed of occurrence of the beats for a given metric structure. In a musical score, the tempo is specified in terms of the number of metric units per minute, for example, quarter-note = 60, in which the time value of each quarter-note is 1 second. The inverse of tempo, the time between beats, is called the beat period. [1]

Temporal - An adjective meaning "pertaining to time." [4]

Temporal acuity - The degree to which the auditory system can resolve, or separately distinguish, events separated by extremely brief time periods. [1]

Temporal coherence boundary - Defines the threshold for hearing a repeating two-tone sequence as composed of a single auditory stream across a range of frequency differences between the tones and rates of tone presentation when the listener is trying to hear a single stream. Above the boundary, the sequence is always heard as two streams. Below it, the sequence may be heard as a single stream. This boundary is contrasted with the fission boundary, which defines the threshold for hearing the same kind of repeating sequences when the listener is trying to hear two separate streams. Above the fission boundary, the sequence may be heard as two streams, but below it the sequence is always heard as a single stream. [1]

Temporal lobe - A region of the lateral part of cortex (just center of and slightly behind the ears) concerned with audition and containing primary auditory cortex (i.e., the first cortical area to which auditory signals are relayed, also known under the name of Heschl's gyri). [1]
Temporal structure - A sequence of events having a specific set of time intervals between the onsets of successive events. Sequences having different onset-to-onset intervals are said to have different rhythmic structures or temporal structures. [1]

temporary threshold shift (TTS) - a brief, transitory increase in an individual animal's hearing threshold in response to exposure to sound. All humans typically experience such shifts, such as the effect that occurs after leaving a noisy room for a quiet location. For a period of time, hearing sensitivity is decreased such that quiet sounds are not perceived. TTS recovers so that original hearing abilities return. Minor amounts of shift (3-5 dB) may recover in minutes; large shifts (40 dB) may recover overnight, and major shifts (>45 dB) may require days or weeks to recover. Above 65 dB the shift may not fully recover. TTS generally occurs in a limited or affected frequency band at sound intensities well above hearing threshold levels. Using NMFS interim guidance (based on human hearing data), the difference between the threshold of hearing and sound intensities that result in annoyance (or possibly TTS) in marine mammal is approximately 80 to 100 dB. For the experiments covered by this assessment, the more conservative value of 80 dB above threshold will be used throughout. NMFS nevertheless notes that at this time, exposures that cause PTS or TTS have not been measured for mysticetes or sperm whales.

Tensor tympani - Like the stapedius, a small muscle in the middle ear. Contraction of the muscle increases the stiffness of, and thus lessens the amount of energy conducted by, the ossicular chain. Though to a significantly lesser extent than the stapedius, the tensor tympani is involved in acoustic reflex, which is the automatic, protective response of the intratympanic muscles to intense sound stimulation. [3], [5]

THD - The effective DC voltage of an AC signal. The square root of the mean value of the squares of the instantaneous values of a varying quantity. [3]

threshold of audibility - For a specified signal, the minimum effective sound pressure level of the signal that is capable of evoking an auditory sensation in a specified fraction of the trials. The characteristics of the signal, the manner in which it is presented to the listener, and the point at which the sound pressure level is measured must be specified. Also called threshold of detectability. Unless otherwise indicated, the ambient noise reaching the ears is assumed to be negligible. The threshold is usually given as a sound pressure level in decibels, relative to 0.0002 microbar. Instead of the method of constant stimuli, which is implied by the phrase a specified fraction of the trials , another psychophysical method (which should be specified) may be employed.
threshold of detectability - threshold of audibility.
threshold of discomfort - In acoustics, for a specified signal, the minimum effective sound pressure level of that signal which, in a specified fraction of the trials, will stimulate the ear to a point at which the sensation of feeling becomes uncomfortable. The term applies similarly for other senses.
threshold of feeling - In acoustics, for a specified signal, the minimum sound pressure level at the entrance to the external auditory canal which, in a specified fraction of the trials, will stimulate the ear to a point at which there is a sensation of feeling that is different from the sensation of hearing. Also called tickle.

threshold of hearing - The lowest level sound that can be perceived by the human auditory system. This is close to the standard reference level of sound pressure, 20 µPa.

threshold of pain - In acoustics, for a specified signal, the minimum effective sound pressure level of that signal which, in a specified fraction of the trials, will stimulate the ear to a point at which the discomfort gives way to definite pain that is distinct from mere non-noxious feeling of discomfort. The term applies similarly for other senses.
threshold sensitivity - In acoustics, for a specified signal, the minimum effective sound pressure level of that signal which, in a specified fraction of the trials, will stimulate the ear to a point at which the discomfort gives way to definite pain that is distinct from mere non-noxious feeling of discomfort. The term applies similarly for other senses.
THX - A division of Lucasfilm, San Rafael, California. Also, a set of specifications for the enhancement of sound playback in the residential environment. [3]

Timbral - Refers to the overall frequency balance of a system. In a perfect world, all systems would have complete tonal neutrality. With current technology, this ideal is approached but not met. Listening to many equally "good" speakers will reveal that some sound warmer than others, some sound brighter etc. In a surround sound system it is important that all speakers have a close timbral match for the highest degree of sonic realism.

Timbre - Also referred to as sound quality or sound color. The classic
negative definition of timbre is: the perceptual attribute of sound that allows a listener to distinguish among sounds that are otherwise equivalent with respect to pitch, loudness, and subjective duration. Contemporary research has begun to decompose the attribute into several perceptual dimensions of a temporal, spectral, or spectro-temporal nature. [1]

Time Delay Spectrometry (TDS) - A method, conceived by Richard Heyser, that permits a spectrum that has been delayed to be measured with the signal delay removed. TDS measures in the frequency domain, then transforms the results mathematically for interpretation in the time, energy or frequency domains. The principal advantages of TDS measurements are superior noise and distortion rejection properties, fast data gathering capability, and the ability to make acoustical measurements under actual use situations. TDS measurements include the frequency response, phase response, and time response data associated with other techniques, plus energy-time curves, polar energy-time curves, and energy-time-frequency curves (3-D displays). [3]

Time Weighted Average (TWA) - The yardstick used by the Occupational Safety and Health Administration (OSHA) to measure noise levels in the workplace. It is equal to a constant sound level lasting eight hours that would cause the same hearing damage as the variable noises that a worker is actually exposed to. (This hearing loss, of course, occurs over long-term exposures.) Same as LOSHA.

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time-delay spectrometry - A sophisticated method for obtaining anechoic results in echoic spaces.
time-of-flight - Technique for calculating the distance to a target by using the timing of the return echo from the target and the speed of sound in the medium between the target and the sensor. Used in echo location and ultrasonic flowmeters.

Tinnitus - A sensation of noise, frequently of ringing, in the ears. Tinnitus aurium refers a subjective sensation of noises in the ears. Objective tinnitus refers to abnormal or pathological sounds originating within the body, in the region of the ear, which are audible to others than the subject. [3], [7]

Tip - The end most contact of a 1/4" (and 1/8" mini) phone connector to which the hot (positive) wire is attached to.
Tonal - In reference to audible sound, capable of exciting an auditory sensation having pitch.

Tonal system - A set of musical rules that characterize Western music since the Baroque (17th century), Classical, and Romantic styles. This system is still quite prominent in the large majority of traditional and popular musics of the Western world. Other musical systems in use in the West do not conform to these rules, and are consequently called non-tonal or atonal. [1]

Tone - In reference to audible sound, capable of exciting an auditory sensation having pitch.

tone burst - A short signal used in acoustical measurements to make possible differentiating desired signals from spurious reflections.


tone control - An electrical circuit to allow adjustment of frequency response.
An equalizer control. A control that changes the tone of a sound.
tone squelch - A squelch system (used in wireless equipment) whereby the transmitter emits a tone at an inaudible frequency. The receiver, upon detecting any signal checks to see if that tone is present. If so, it allows the main signal to be heard, otherwise it stays muted.

Tonic - The principal note or chord of a key in the Western tonal system. [1]

total harmonic distortion (THD) - Refers to a device adding harmonics that were not in the original signal. For example: a device that is fed a 20Hz sine wave that is also putting out 40Hz, 80Hz, etc. Not usually a factor in most modern electronics, but still a significant design problem in loudspeakers.

transducer - A device for changing electrical signals to acoustical or vice versa, such as a microphone or loudspeaker.
A device capable of being actuated by energy from one or more transmission systems or media and of supplying related energy to one or more other transmission systems or media, as a microphone, a thermocouple, etc. The energy in input and output may be of the same or different types (e.g., electric, mechanical, or acoustic).
A device that converts one form of energy to another. Examples are loudspeakers which change electrical energy into acoustical energy and microphones that change acoustical energy into electrical energy.
transducer gain - The ratio of the power that a transducer delivers to a specified load under specified operating conditions to the available power of a specified source. If the input and/or output power consist of more than one component, such as multifrequency signal or noise, then the particular components used and their weighting must be specified. This gain is usually expressed in decibels.

transformer - An electrical device consisting of a magnet with wires coming in and would around it on one side, then another set of wires wound around it on the other side. It allows isolation of one side to the other since the wires are not actually touching each other but it still allows (alternating) electrical current to pass. Depending on the ratio of the number of times the two different wires are wound around the magnets, it will also change the amount of voltage/wattage passed through it such as changing a microphone level signal to a line level signal. Power transformers step-up or step-down electricity that's then used to power other electrical devices at a different voltage.

transient - A short-lived aspect of a signal, such as the attack and decay of musical tones.

transient response - The ability of a component to respond quickly and accurately to transients. Transient response affects reproduction of the attack and decay characteristics of a sound.

Transients - Instabilities present in the oscillation pattern of a physical object that is set into vibration before the object settles into a stable oscillation. Also called attack transients (see amplitude envelope). Similar oscillatory instabilities ("legato transients") can be observed when the object changes state suddenly as occurs when a musical instrument changes pitch (by changing fingering on a woodwind instrument, pushing on a valve or piston in a brass instrument, pressing down on a string with a finger, or lifting one up on a string instrument). Transients are often characterized by a noisy or inharmonic spectrum. [1] (See also harmonicity, noise, spectrum.)

transmission loss - Of a partition, for a specified frequency or frequency band, difference in decibels between the average sound pressure levels in the reverberant source and receiving rooms, plus ten times the logarithm of the ratio of the area of the common partition to the total Sabine absorption in the receiving room. Unit, decibel (dB); abbreviation, TL.
transmit current response - (TCR) The level of the acoustic output referenced to one meter (one foot in air) per one amp input.
transmit voltage response - (TVR) The level of the acoustic output referenced to one meter (one foot in air) per one volt input.

transmitter - In a wireless microphone system, the device that transmits the audio signal output from the microphone through the air as a radio frequency. In a lapel system it's sometimes referred to as a 'body-pack'. This is where the microphone plugs into, where a battery is stored, and where the electronics are that change the audio signal so it can be sent out an antenna and into the air to be picked up by a receiver at another location.
transonic - Pertaining to that which occurs or is occurring within the range of speed in which flow patterns change from subsonic to supersonic or vice versa, about Mach 0.8 to 1.2, as in transonic flight, transonic flutter ; that operates within this regime, as in transonic aircraft, transonic wing ; characterized by transonic flow or transonic speed, as in transonic region, transonic zone.

transonic flow - In aerodynamics, flow of a fluid over a body in the range just above and just below the acoustic velocity. Transonic flow presents a special problem in aerodynamics in that neither the equations describing subsonic flow nor the equations describing supersonic flow can be applied in the transonic range.
transonic speed - The speed of a body relative to the surrounding fluid at which the flow is in some places on the body subsonic and in other places supersonic.
transparency - Listening term. An analog that can be best "pictured" in photography. The more "transparent" the sound, the clearer the auditory picture.

transponder - A device that automatically transmits sonar signals when actuated by a specific sonar signal from an interrogator. Transponders are used to mark or track objects or sites underwater. They are programmed to be in a continuous passive (listening) mode until they receive a valid signal from a transponder interrogator.
transverse wave - Wave in which the direction of displacement at each point of the medium is parallel to the wavefront.

traveling frequency - The range of frequencies in the VHF band from 169 to 172 MHz designated for radio devices that are not assigned to any particular use. Frequencies above this are used for television but different cities use different television frequencies (channels). Therefore, a wireless microphone can use a television frequency that's not being used by a local TV station. However, a performance group that travels from city to city can not use any of those frequencies since they would only work in half the cities. Therefore, they use a "traveling" frequency hat will work in any city depending on who else is using that frequency near them.
treble - Refers to the higher frequencies. Technically, the treble clef in music is for frequencies above 329 Hz (E above middle C), but in equalizer terms refers to higher frequencies typically above 4kHz.

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Triad - The simultaneous sounding of a group of notes, usually three or more. In Western music, chords of three notes consisting of the first, third and fifth degrees of a scale are called triads. Major triads consist of intervals of a major third (four semitones) and perfect fifth (seven semitones) with respect to a reference pitch (the root). The third is minor (three semitones) in a minor triad. The third is major and the fifth is augmented (eight semitones) in an augmented triad. The third is minor and the fifth is diminished (six semitones) in a diminished triad. When the notes of a chord are played in ascending or descending succession, the melodic figure is called an arpeggio. [1]

tri-amp - The speaker amplification method where a speaker system has three main components being the high, mid, and low. Each is powered by a separate amplifier channel (fed by an active crossover).
triboelectric noise - The variation/modulation of cable capacitance (electrostatic charge due to friction) against the load impedance that causes the audibility of noise from a cable when it's moved. Cable handling noise.
trim control - The gain control on a mixer or similar device.

Trimodal - In the home entertainment context, pertaining to the auditory, visual and haptic sensory modalities. [3]

tube traps - Proprietary sound-absorbing units.
tuning frequency - The helmholtz resonant frequency of a box. Also refers to the resonant frequency of other types of systems.

Tuning system, musical - A set of pitches (or notes) arranged with certain intervals among them within the span of an octave (see also pitch). The scale pattern generally repeats in each octave. Each note constitutes a degree of the scale. Each diatonic scale consists of intervals between adjacent notes that are either minor or major seconds (one or two semitones, respectively). The different arrangements of major and minor seconds yield different modes. The two most important modes in Western tonal music are the major and minor modes. The chromatic scale contains all twelve semitone steps within an octave. Another kind of scale which does not fall within the tonal system but which was used extensively in the music of Debussy and Ravel is the whole-tone scale, which has only six notes, all separated by whole tones. Intonation (or tuning system) refers to the exact tuning of the notes of a given scale system. The most widely used tuning system in Western music is the equal-tempered system in which all intervals can be expressed as integer multiples of a standardized semitone. This system was brought to Europe from China and adopted during the 17th century. [1]

Tweeter - Speaker drivers that reproduce high frequencies.
Tympanic membrane (eardrum) - A thin, translucent, elliptically-shaped and slightly concave membrane at the end of the meatus. The eardrum is made up of four layers. The outermost layer is continuous with the skin of the meatus, and the innermost layer is continuous with the mucous membrane of the middle ear. Of the two inner layers, the outer layer is composed of radial fibers, while the inner layer is composed of non-radial fibers. The tympanic membrane attaches to the malleus (hammer) of the middle ear. [3], [5]

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UHF - Ultra High Frequency. Usually 300MHz to 3000MHz.
Ultrasonic - In acoustics, of or pertaining to frequencies above those that affect the human ear, i.e., more than 20,000 vibrations per second.
The term ultrasonic may be used as a modifier to indicate a device or system intended to operate at an ultrasonic frequency, as an ultrasonic vibrator. Supersonic was formerly used in acoustics synonymously with ultrasonic; this usage is now rare.
ultrasonic frequency - Frequency higher than the nominal audio frequency range. Unit, hertz (Hz). The term is commonly applied to elastic waves propagated in gases, liquids, or solids.
Ultrasounds - Sounds of a frequency higher than 20,000 Hz. The frequency region containing these frequencies is called the ultrasonic region.

Unbalanced - A wiring method which uses two conductors to provide a simple positive and negative circuit. Does not provide any noise filtering capabilities. Found in cheaper audio equipment.
unidirectional microphone - A cardioid microphone. Literally, one that picks up from only one direction.
unshielded cable - A cable with no shielding; typically speaker cables.

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VCA - Voltage controlled amplifier. A circuit design that allows remote control of a signal. Typically used in high-end groupings on mixers. A VCA group is one where the group fader sends a signal to the individual channels assigned to it to adjust their levels in the individual channels as compared to sending their signals to the subgroup to control.
VHF - Very High Frequency. Usually 30MHz to 300MHz.
Vibration - Vibration is a force which oscillates about some specified reference point. Vibration is commonly expressed in terms of frequency such as cycles per second (cps), Hertz (Hz), cycles per minute (cpm) or (rpm) and strokes per minute (spm). This is the number of oscillations which occurs in that time period. The amplitude is the magnitude or distance of travel of the force.

Vibration Isolator - A resilient support that tends to isolate a mechanical system from steady state excitation.
Virtual auditory environment - A perceived auditory environment which has been manipulated so that it does not correspond to the immediate physical environment. A trivial example is the use of headphones, which typically foster the sense of sound originating within the head, while the physical situation contains two sound sources located on either side of the head. [3]

Visual capture - The phenomenon is which visual perception dominates when visual cues and other sensory cues--auditory, proprioceptive, haptic, etc.--are in direct conflict. In audio design, the effect allows a loudspeaker to be placed at some distance away from a video display without the audience perceiving the disparity in location between the visual event generated on the screen, and the sonic event generated in the distant speaker. There are limits to vision's tendency to "overpower" the other senses: In the case of audio design, the limits can be usefully defined in terms of angular disparity, beyond which the audience "hears" the sonic event as being spatially distinct from, and thus conflicting with, the locus of the visual event. [3]

voice coil - The wire coil wrapping of an electromagnet placed in a permanent magnetic field and attached to the diaphragm of a speaker. The part of the speaker driver that moves based on the electric current passed through it and thereby moves the diaphragm to produce sound.
volt - The unit used to measure the potential, force, or amplitude of an electric signal. Abbreviated "V".
Volume - The cubic space of a room bounded by walls, floors, and ceilings determined by the Volume=Length x Width x Height of space. Volume influences reverberation time.

volume of air - Literally, the amount of air within a given space (in three dimensions). The amount of space (air) within a room directly affects the acoustic properties of the room.
VU - Volume Unit. Very similar to dBm expect in its application. VU is for program material, dBm is for a steady sine wave (usually 1kHz).
VU meter - An indicator calibrated and used to measure the power level of the complex waveforms of an audio signal.

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Warmth - In concert hall acoustics, warmth is defined as liveness of the bass, or fullness of the tone between 75 and 350 Hz, relative to that of the mid-frequency tones (350 to 1,400 Hz). Musicians sometimes describe as "dark" a hall that has too strong a bass, or whose high frequencies are greatly attenuated. [2]

Watt - The unit of electrical or acoustical power.

Wattage - Is the unit of power used to rate the output of audio amplifiers. For a wattage number to have meaning the distortion level and impedance must also be specified.

Wave - An oscillation of something. Specifically in audio referring to either the oscillation air pressure in a sound wave, or the oscillation of voltage in an electrical audio signal. Just like a wave on the ocean where it goes up and down, the voltage of an audio wave goes up and down and our ears eventually interpret that oscillation as sound.

Waveform - A graph of the voltage levels of an audio signal with amplitude being the Y-axis and time being the X-axis. The "picture" of an audio signal's wave pattern.

Wavefront - For a progressive wave in space, continuous surface that is a locus of points having the same phase at a given instant.

Wavelength - Sound that passes through air produces a wavelike motion of compression and refraction. Wavelength is the distance between two identical positions in the cycle or wave. Similar to ripples or waves produces by dropping a stone in water. Length of sound wave varies with frequency. Low frequency equals longer wavelengths.

Weber's law - Discovered by Ernest Heinrich Weber in 1834. States that the smallest detectable change (jnd) in intensity is a constant fraction of the level of stimulation. Georg Fechner turned Weber's law into a psychophysical logarithm of the magnitude of stimulation (I), or S = k log I. A great deal of psychophysical research has attempted to establish the Weber-Fechner law for sensory dimensions other than intensity, e.g., frequency and duration in audition. While the empirical data conform fairly well to the law over a certain range of values for each dimension, they can differ substantially at extremes of the range of perceptible values. [1]

Weighted decibels - Most sounds consist of a broad range of sound frequencies. Because the human ear is not equally sensitive to all frequencies, several frequency-weighting schemes have been used to develop composite decibel scales that approximate the way the human ear responds to sound levels. The "A-weighted" decibel scale (dBA) is the most widely used for this purpose.
weighting - Adjustment of sound-level meter responses to achieve a desired measurement.

Wet signal - An audio signal that's been processes, usually with some sort of effects. (Not a mixer with coffee spilled on it.)
white noise - Random noise having uniform distribution of energy with frequency.

Whole-tone scale - A set of pitches (or notes) arranged with certain intervals among them within the span of an octave (see also pitch). The scale pattern generally repeats in each octave. Each note constitutes a degree of the scale. Each diatonic scale consists of intervals between adjacent notes that are either minor or major seconds (one or two semitones, respectively). The different arrangements of major and minor seconds yield different modes. The two most important modes in Western tonal music are the major and minor modes. The chromatic scale contains all twelve semitone steps within an octave. Another kind of scale which does not fall within the tonal system but which was used extensively in the music of Debussy and Ravel is the whole-tone scale, which has only six notes, all separated by whole tones. Intonation (or tuning system) refers to the exact tuning of the notes of a given scale system. The most widely used tuning system in Western music is the equal-tempered system in which all intervals can be expressed as integer multiples of a standardized semitone. This system was brought to Europe from China and adopted during the 17th century. [1]

Windscreen - A cover placed on a microphone to protect it from wind. Normally, the air (other than sound waves) moving across a microphone will cause pops, whistles, and thumps. A windscreen minimizes these sounds.

Wireless microphone - A microphone system that has the microphone capsule attached to a radio transmitter. The transmitter takes the audio signal from the capsule, changes it into a radio signal, and transmits it. A matching radio receiver takes the radio signal, converts it back to an audio signal, and outputs it usually to a mixer. This is opposed to a standard microphone where the capsule is connected to the mixer by continuous wiring. The rule for using wireless mics is that if it doesn't move, it doesn't need to be wireless. Wired mics are still much, much better than even the best wireless mics.

Woofer - Term for low frequency speaker drivers.

Wow - A slow frequency change in an audio signal when playing back a pre-recorded signal. This is causes by a maladjusted or physically limited mechanical component in the medium transport system.
wye-connector - A wiring design of one connection to multiple others or from multiple connections to one. I.E. the output of one device directly wired to the inputs of several devices. Note: wyeing an output to several inputs will often work, but there's a loss of signal for each split. Wyeing multiple outputs to a single input usually will NOT work or at best will offer significant loss of signal due to impedances of electronic wiring.

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XLR - Type of connector developed by Cannon company. It's the standard connector used for all professional microphone wiring and some line level wiring. Typically indicates balanced wiring. Standard microphone wiring is for pin 1 to be the shield, pin 2 is the + (positive/hot), and pin 3 is - (negative). Typically three pin connectors, but may be more (i.e., 4, 5, 6, etc.).

X-Y mixing - Procedure of positioning two microphones such that their elements are in close proximity to each other, but aimed at different vectors. Variations include the elements directly above each other, or simply with the grilles touching. Typically used in stereo mixing practices, but is mono compatible. Useful in creating altered polar patters from what each microphone offers independently while minimizing comb filtering.