Near Field / Close Field: - The area which is close to the source. If we take a mic and place it right up against a sound source, we will be picking up it's sounds as they are in the near field, and if we take the microphone and place it far away from the sound source, we would be picking up the sounds (so long as it isn't too far away!) as they are in the WIDE field. Most commonly used to describe small loudspeakers which are designed to sound at their best a metre or two away from the listeners ear, hence lessening (but not eliminating the effects) of sound radiation in an acoustically imperfect room.

Noise Gating / Noise Gate: - see "Dynamics Processing".

Non Linear Recording / Editing: - An advantage of the way digital data is stored / retreived (as separate "bits" of information, is that these bits of information can (in theory) be accessed and manipulated in any order (Random Access). In terms of digital audio and video this means that recorded material may be accessed and edited easily in a random, or non linear way, without physical manipulation of a medium such as tape (rewinding, splicing etc).

Noise Floor: - Amount of background noise produced by a piece of audio hardware, measured in dB's.

Normalise / Normalised / Normalled: - To boost the amplitude of a digital sound so that it is as high as it can be without clipping (0 dB). This is done by taking the highest level, then adjusting the rest of the signal accordingly.

Normalised / Normalled Connection: - A connection which lets a signal pass through it when no plug is inserted in it, but breaks the connection when a plug IS plugged into it. Most commonly found in "Jack" form (in the U.S. this connection is known as a "break-jack") in mixing desks and patchbays.

Note: - See Pitch and Octave.

Null Point: - See "Zero Crossing Point".

Nyquist Theorem / Frequency: - Theorem which deals with the digital audio problem of "Aliasing". The Nyquist theorem proves that the highest frequency recordable through digital sampling technology (without the horrible distortion caused by aliasing) will be half that of the sampling rate used. In practice, the sampling rate used should be @10% more than double. This is due to the fact that the Anti Aliasing filters used in the Analogue to Digital conversion process, despite having a very sharp roll off, do not reach their 0dB cutoff points until they are @10% higher also.

An example of this is the "Red Book" standard which governs the production of nearly all audio CD's. Here, in order to record "full frequency" audio up to 20 kHz the specified sampling rate is 44.1 kHz, this allows for the problem that the anti aliasing filters will have started rolling off at 20khz, finally reaching their cut off point @ 22.05kHz.

Octave: - Measure of the distance between one note and another note which has a frequency that is twice as many hertz. Encompasses 12 semitones, or 12 keys (including sharps/flats) on a keyboard.

Due to the laws of harmonics, a note which has double / half the frequency (and multiples thereof) will have similar tonal characteristics, hence In the western system of music, this means that the note will have the same name, but the one of double the frequency will have a number which is one higher than the note which has half the frequency (eg "A4" will usually have a pitch of 440 Hertz which means that "A5" will have a frequency of 880 Hertz and will be 12 semitones / 1 octave above). See also Pitch.

Ohm / "Ohm's Law": - Ohm's Law is one of the fundamental laws of electronics, and pertains to the relationship between current and voltage / resistance in an electrical conductor. This relationship states that "Current = Voltage / Resistance". The usual way of expressing this in mathematical terms is "I = V/R", or to make things confusing, you could also say that "V = I / R", or R = V / I. The current is measured in "amperes" or "amps" the voltage is measured in "volts" (duh!) and finally, the resistance is measured in OHM's.

Ohm: - So as we can see from above, an "Ohm" is a measurement of the resistance in an electrical conductor. Which can be calculated using the R = V / I equation above. Hence, when someone says that their speakers have an "Impedance" of 8 Ohms, the "impedance" is referring to the factor by which the electrical signal is impeded, hence, a 4 Ohm speaker will offer half the resistance to the electrical current flowing through it than an 8 Ohm one. Having said this impedance varies greatly, and impedance ratings are usually just an average. For more on this, impedance.

Omnidirectional: - See Polar Pattern.

Oscillator: - see "Synthesiser" .

Overdub: - Adding something to a previous recording, so that the two (or more) parts may be subsequently played together as a synchronous whole. A part of Multitrack Recording.

"P.A." / P.A. System: - Acronym of "Public Address". A sound system that is capable of addressing alot of people at one time.

Phantom Power: - A special +48V DC power supply for the use of Condenser type microphones. It is known as "phantom" power as the power travels through the same cable as the audio signal.

Pickup Pattern (microphone): - see Polar Pattern (below).

Pinch roller: - A roller on a tape machine (usually rubber) which "pinches" or presses the tape against the capstan, in order to pull the tape tightly across the head(s) of the machine.

Pitch: - The fundamental frequency of a sound.

In music, certain fundamental frequencies / pitches are measured at regular intervals through the frequency spectrum and grouped according to their frequencies and harmonic relationships. These related pitches are described as "notes". In western music, these notes are usually designated with letters from "A" through to "G", and numbers that designate which octave they belong to.

Concert Pitch: - In western music "concert pitch" is a standard reference which defines the fundamental frequencies of musical notes. This current universal standard set by the International Organization for Standardization in 1955 (though it was in common usage since 1939), and defines that the A of the fourth octave "A4" should be 440 Hertz (aka "A440"). Before this, the usual standard was the 1859 "Diapason Normal" where A = 435Hz. Previous to this, the A4 frequency varied in different times and locations between roughly 380 and 480 Hertz. The most common kind of tuning forks vibrate at 440 Hz.

Pitch-shift: - alteration of the pitch or frequency of sound, but without adjusting the Tempo.

Pitch Wheel: - Small rotating wheel, usually on a keyboard / synthesiser which increments / decrements the pitch of the note being played.

Polar Pattern (or Pickup Pattern / Directional Pattern): - A polar pattern is a picture or graph of a transducer's sensitivity to soundwaves.

In microphone terms, this is the sensitivity to incoming sound waves taken at various angles within a 360 degree circumference. In loudspeaker terms, it is it's sensitivity in terms of the soundwaves that it is putting out within the same 360 degree circumfrerence.

Regarding the polar patterns of microphones, there are general patterns, eg "unidirectional", "bi-directional", "omnidirectional" etc, and more specific interpretations of these general patterns, eg "cardioid", "figure of eight" etc. These are explained below.

Unidirectional: - Will provide a very high sensitivity to sound coming from one direction, but a very low sensitivity to sound coming from other directions.

Bidirectional: - Will provide a very high sensitivity to sound coming from the front and the rear, but a very low sensitivity to sound coming from the sides.

Omnidirectional: - Will pick up sound from all angles equally (more below).

There are several kinds of specific, defined polar patterns for microphones, some of which are listed below...

Cardioid (unidirectional): - A microphone pickup pattern that is characterised by the shape of a "loveheart" emanating from the capsule of the microphone. It should display a high sensitivity to sounds which are produced in front of the capsule, and a very low sensitivity to sounds which are produced behind it. There are also Supercardioid and Hypercardioid pickup patterns which are similar, but have a narrower pattern at the front, and a little more sensitivity at the rear.

Figure of Eight (bi directional): - Polar Pattern which has the appearence of the figure eight, ie will be very sensitive to sounds at the front and rear of the microphone, but not at the sides.

Omnidirectional: - Will pick up sound from all angles equally. An omnidirectional polar pattern should adhere very closely to that of a circle / sphere. There are also Half - Omnidirectional (hemispherical) microphones which do the same thing, only over 180 degrees rather than 360. "PZM" (Pressure Zone Mic) microphones are an example of this.

Polyphonic / Polyphony: - ability for musical device (keyboard etc) to play more than one note at the same time. If an instrument is say, 64 note polyphonic, it has the ability to play up to 64 notes at the same time. See also Monophonic.

Portamento: - Instrumental technique of sliding directly between one note / frequency and another without defining any of the notes inbetween. See also Glissando and Vibrato.

Potentiometer / "Pot": - The sliding, variable resistance device beneath any knob that adjusts the level of something.

Program Change: - MIDI term which describes a message sent within the MIDI system telling it to change the "program" or "patch" (sound) of the MIDI instrument being played, or in the case of a MIDI effects unit, the effect being used.

Quantize: - Sequencers ability to make notes / beats recorded conform to the nearest subdivision of a bar. These subdivisions may be predetermined by the user (e.g. 1/64, 1/16 etc). A useful tool in the correction of timing errors, however overuse may result in the performance having a somewhat "robotic" feel.

Rectifier: - Electronic device which is used to keep the direction of flow in AC electricity constant. They are a vital element in the power supplies of all electronic devices which run on domestic mains (AC) electricity.

"Red Book" Standard: - Standard set by the Phillips and Sony corporations which governs the audio standard for virtually all audio CD production. Instituted to ensure compatabilty between CD's and their players, it states that audio should be of a standard which is 16 bit, uncompressed and recorded with a sample rate 44.1 kHz per second. On a computer, audio files recorded at these rates are usually known as "WAV" files.

Resistance: - This is the amount of opposition or yes, resistance! to a flow of electrical current, and is measured in Ohm's, which is sometimes represented by the Greek symbol for Omega. In electronic's, copper, aluminium, gold and silver offers very little resistance to electric current, and are commonly known as "conductors". At the other extreme, rubber and most plastics offer ALOT of resistance, and are usually known as "insulators". Resistance is normally dissipated as heat.

Usually, resistance increases with temperature in a "conductor" and decreases with an insulator. For more on this, see Ohm / Ohm's Law, Impedance and Current.

Resistor: - An electronic component that is designed to have a set value of electronic resistance, measured in Ohms. Is used extensively in electronic circuitry for current control and protection.

Reverb / Reverberation Unit: - Electrical / Mechancal / Both kind of device to add to add the effect of reverberation (see below) to a sound / signal. See also echo and effects processing.

Reverberation: - gradual decay of a sound due to multiple echos reflecting from the many surfaces of an acoustic environment. See also echo and effects processing.

RMS: - Acronym of Root Mean Square, it is a measure of the average level of a signal (by squaring then averaging the voltages produced by a signal). "RMS Continuous" is usually the most conservative (and the best) way of estimating the power output of an amplifier, or the power handling of loudspeakers, and the most common way of defining AC voltage.

Roll-Off: - Rate of attenuation of a signal (usually by a filter), measured in Decibels per Volt (DbV)

Sample: - When a sound is converted from analogue to digital format, the amplitude of the signal is sliced into many segments of binary information and analysed, these slices are measured per second (for a standard audio C.D. this is carried out 44,100 times) thus we may say that a C.D. has a "sample rate" of "44.1khz". Rather like the "pixels" of a visual image, the more "samples" taken per second, the higher the resultant sound quality.

Sampler: - Device which has the ability to record sounds digitally, as decribed above, then assign a musical pitch value to that sound so that it may played as musical notes on a compatible instrument (usually a keyboard).

"Multisampling": - When a sampler records a musical instrument accurately at a certain pitch, then that pitch should be reproduced accurately. If, however you stray up or down the keyboard by a few octaves, you may find that the pitch is less accurate, and has "drifted" somewhat. When this is the case it is necessary to "multisample" or make multiple recordings of the original instrument at certain points in the musical scale (eg every octave) to keep the drift under control. This is known as "Keygrouping".

When the correct procedure for "keygrouping" (assigning an accurate central pitch and keeping the amount of surrounding pitches covered to a reasonable limit) is followed, then the pitches within the keygroup should be a reasonably accurate with a (more or less) inaudible amount of "pitch-shift" (alteration of pitch).

Sawtooth Wave: - see Wave.

Scale: - An ascending or descending sequence of stepped notes / pitches. A scale is designated by the first note (eg C major), which is known as the " tonic" (from tonal). There are several different kinds of scale (eg diatonic, pentatonic etc). Notable among these are:

Chromatic scale: Encompasses all twelve semitones / half steps (see below) in an octave as they are represented on the keys of a keyboard. In western music, all other scales are subsets of the chromatic scale.

Diatonic scale: Most western music is composed using diatonic scales. Consists of seven notes. Whereas the chromatic scale is divided into twelve even semitones and is keyless, the diatonic scale uses five whole tones and two semitones (assuming an "equal tempered" tuning system is being used). Diatonic scales are written or played either in a "major" or "minor" key, depending on the pattern of intervals in terms of tones and semitones. A major diatonic scale will progress:

Tone (or Whole Tone / Whole Step), Tone, Semitone (Half-Step), Tone, Tone, Tone, Semitone.

On the other hand, a (natural) minor diatonic scale will progress:

Tone, Semitone, Tone, Tone, Semitone, Tone, Tone.

C Major Scale.	C Minor Scale.

Semiconductor: - Material / Substance that is at a mid way point between being a conductor and an insulator. This property is invaluable for creating transistors, which need to be capaple of switching between these two states. Examples of semiconductive materials include Silicon (cheap and most widely used) Germanium, and Gallium Arsenide, which is a compound of gallium and arsenic.

Semitone: - Short interval which in the western "equal tempered" system of tuning corresponds to one twelfth of an octave. Sometimes known in the US as a "half step".

Sequencer and Sequencing: - see "M.I.D.I.".

Shock Mount: - Device for holding a microphone, which is designed to provide shock absorbtion / insulation from any vibrations which may be transmitted through a microphone stand. Usually used with particularly sensitive condenser microphones.

Sibelius: - Brand name for the most well known form of music notation software (software which transposes what is played into a musical score). Also a dead Scandinavian composer!

Signal: - In electronics / audio etc a signal is a transmission of either a pulse or continuously fluctuating electrical value through a conductive medium. In music, this can either be an electronic representation of a sound (eg piano, vocals etc), or a sound that has been originally generated though electronic means (eg synthesiser).

Signal Chain: - Path taken by a signal. This can either be from the input to the output of one device, or the path taken through many different devices (eg from microphone to mixing desk / signal processing devices then amplifier(s), speakers etc)

Signal Feed: - see Feed.

Signal Processing Device (SPD):- Any device placed in a signal chain (see above) which intentionally alters the signal passing through it in some way (eg noise gate, compressor, reverb etc)

Signal to Noise ratio (S/N): At it's most basic, this is the difference between the level of background noise (noise floor), and the level of signal, measured in dB's.

Sine Wave: - see Wave.

Slave: - A device which is controlled by another device, which is referred to as the master.

Solid State: - Pertains to the solid qualities of a (usually crystalline) substance. In electronics, this usually means semiconductor materials. In the olden days, when transistors were still slugging it out with valves in amplifiers, radios etc, transistor devices were known as "Solid State" devices, due to their use of semiconductive "solid state" materials.

Sound Synthesis: - Bringing together different electronic sound elements (oscillators*, filters*, envelope generators* etc to make new, harmoncally interesting sounds. In the case of music to be played as notes.

Additive Synthesis: - The synthesis of a complex sound using a collection of "simple" pure tones or sine waves.

Subtractive Synthesis:- The opposite of Additive Synthesis (see above) The synthesis of a new sound by the refinement through filters etc of a harmonically complex waveform.

See also Synthesiser and Wave.

Soundwave: - See Wave

S.P.L. : - Sound Pressure Level, measured in Decibels (dB's).

Square Wave: - see Wave.

Step Up / Step Down Transformer: - see Transformer.

Sub-Bass : - Bass frequencies which are below the point where sound is directional (@ 150Hertz) and above the point where it can no longer be heard (@20 Hertz). below this, it is known as "infra bass". It is the fact that sound is not directional below 150 Hz (you dont need a stereo pair to recreate its position in space) which enable the design of loudspeaker systems with solitary sub bass units which may be tucked away behind sofa's etc!

Supercardioid: - see Polar Pattern (cardioid).

Supply Reel / Take up reel : - On a cassette / video / reel to reel etc tape, the reel on the left is known as the Supply Reel, and the reel on the right is known as the Take Up Reel.

"Sweet Spot": - The optimum position for a listener within the sound field created by a pair of stereo speakers, or the optimum position for a microphone relative to it's pickup pattern and the sound field created by whatever is being recorded.

Synclavier: - Highly complex (in the old days anyway!) digital synthesiser/ music workstation developed by Sydney Alonso (hardware) and Cameron Jones (software) at Dartmouth College, New Hampshire, United States. The first prototype was released in 1975. Like the Fairlight mentioned above, the Synclavier made a great impact on the increasingly digitally based music of the 1980's. The current homepage of the Synclavier is here .

Synthesiser: - Electronic musical instrument capable of performing functions defined above, usually keyboard based.

*Envelope Generator: - The way that synthesised sound is shaped, most common form being the "A.D.S.R." (Attack. Decay. Sustain. Release.) envelope.

*Filter: - Electrical circuit designed to boost or attenuate certain frequencies within the sound spectrum.

*Oscillator: - Electrical circuit designed to generate sonic waveform.

See also Sound Synthesis and Wave .

Take Up Reel: - see Supply Reel / Take Up Reel.

"T.H.D.": - Acronym of Total Harmonic Distortion (see also Harmonic(s)).

Talkback: - System in a recording studio which enables communication between producers / engineers and musicians when they are working concurrently in different rooms.

Timbre: - The harmonic qualities of a sound.

Tonal (music): - Music composed in a key (major or minor), utilising harmonious sets of notes known as scales. Nearly all western music is composed in this way.

Tonic: - The first note or "tone" of a musical scale. Also known as a "key note" as it is the note which gives us the "key" of the music, or the "home key".

Transducer: - In audio, any device which converts an electrical signal into soudwaves (eg a loudspeaker); or any device which converts soundwaves into an electrical signal (eg a microphone).

Transformer: - (AC) Electrical device which has the ability to incease the voltage of an AC electrical current (step up transformer), or decrease the voltage (step down transformer) through the process of "magnetic coupling". There are also "Isolating" transformers (which result in no change in voltage), and a "Step Across" transformers (ditto). A transformer is usually constructed by coiling two or more lengths of isolated (conductive, usually copper) wire around a magnetic core. It is the amount of "windings" of each around the core that gives the tranformed voltage value of the current. In a step-up transformer, the second coil (which determines the voltage of the output) will have more turns than the first coil. In a step-down transformer, the second coil will have fewer turns.

Transient: - Sharp rise in music / signal level.

Transistor: - The foundation of modern electronics. The transistor (c/f "transresistance") was invented and developed by John Bardeen, Willian Hauser Brittain and William Shockley in the late 1940's at Bell Labs (the first "point contact" tranny was patented by Bardeen and Brittain in 1947).

It has three terminals, and is basically a switching device, which can also be used as an amplifier. It can alternate between two states by using it's ability to act as either a conductor (on), or an insulator (off). When a positive current is applied, then it will be conductive, when a negative current is applied, it will be a non-conductive insulator.

Transistors in Analogue circuits and transistors in digital circuits ...
In analogue circuits (eg audio amplifiers, radios etc) the transistor is used primarily as a device for amplification, and in digital circuits (eg microprocessors, chips etc) they are used primarily as switching devices, switching between being a conductor and an insulator.

Trautonium: - The Trautonium was invented by the German electronics engineer / acoustician Friedrich Trautwein in the late twenties, and was originally manufactured by the Germany's Telefunken company from 1932 to 1935. It is played by depressing a resistive wire against a conductive metal strip, and pitch is adjusted by sliding up and down the wire. It was later enhanced by Trautwein's original assistant, the physicist and composer Oskar Sala with his "Mixtur-Trautonium". Sala, was originally Trautwein's assistant in the development of the original trautonium, and augmented the original design with the addition of envelope generators, filters, oscillators and other enhancements, greatly increasing the sophistication of the instrument. The sound effects for the Alfred Hitchcock movie "The Birds" were created on a Trautonium.

A sample of music made with a Trautonium is available here.

It is played and .

A performer pressed a finger down at a certain position on a wire to produce a tone at a particular pitch. Loudness was controlled by pressing a bar. Timbre was controlled via switches that filtered an initially complex waveform. The sound effects for the Alfred Hitchcock movie "The Birds" were created on a Trautonium.

Trim: - Controls the level of input on a mixing desk.

"Truss Rod": - Metal strengthener placed within the neck of a guitar to prevent warping.

Ultrasonic: - Sound frequencies which are above the highest frequency of human hearing (20 kHz). See also Infrasonic.

Unidirectional: - A microphone response / pickup pattern which is very sensitive to sounds which are produced in front of the microphone, but very INsensitive to sounds which are produced behind the microphone. (see also Polar Pattern)

Variable-Rate Converter: - Digital recording developed originally by the "Kinetix" corporation where the sampling rate "hovers" in a random fashion between 44.1 and 48 kHz. This is done primarily in order to keep sampling errors spread over a wide range of frequencies (when using a fixed rate they may build up around certain frequencies creating noticable distortion). When spread in this way, they are mostly inaudible, with a perceived improvement in sound quality. However, this system, despite it's advantages, may have problems intefacing with other systems which utilize a fixed sampling rate.

VCA (Voltage Controlled Amplifier): - Acronym of Voltage Controlled Amplifier. A device which responds to a control input voltage (usually @ 0-5 Volts DC). As the input voltage increases, so the level of signal decreases by a proportionate amount.

VCF (Voltage Controlled Filter): - Works along the same principles as a VCA (see above), only with a VCF, it is the roll off frequency of a filter which is affected by changes in control input voltage.

VCO (Voltage Controlled Oscillator): - Oscillator whose output frequency is controlled by variations in Voltage.

Velocity (Audio / Acoustics): - The speed at which sound moves through a medium. This depends upon a variety of factors including altitude, temperature and humidity. Allowing for slight variations owing to these factors it is usually between 330 and 350 metres per second. The reference usually used is that in air with a relative humidity of @30% (quite dry) at 0 degrees Centigrade, and at Sea Level (0 feet), Sound will travel through air at a velocity of @ 331.4 metres per second. In your house, at a temperature of @ 20/25 degrees C, it will probably be a little faster.

Velocity (Music & MIDI): - Denotes the speed or force with which a note has been struck. In MIDI , the "Velocity" of a note is a value between 1 and 127. The higher the value, the higher the force that has been used.

Vibrato: - Musical technique which involves const

Volt: - A volt (after the physicist, Count Allesandro Volta) is the amount of elecromotive force required to make one ampere of current flow through one ohm of resistance.

Voltage: - Voltage is what is known as the "potential difference" between two points, in electronics meaning the two points between which a flow of electrical current can be carried. It is this potential difference that helps to create Electromotive Force (EMF) that can move electrons, or other charge carriers between two points. It's unit of measurement is the Volt (above).

"VU" Meter : - An acronym of Volume Unit Meter, and associated with a "Needle and Coil" type of electronic measurement. Measures the level of a signal by using a coil pick up voltage changes (measured as an RMS averaged value).

WAV: - "Windows" Digital file format which is usually 16bit (although it can be 8) and mostly uses a sample rate of 44.1 kHz (although this too may vary).

Wave: - All sound moves as a wave, and the graphic description of a sound is known as a waveform, its shape determined by the levels (amplitudes) of the Fundamental Frequency, and (unless the wave is a pure Sine Wave) the harmonics which follow.

Sine Wave: - Most basic type of wave, and the basic building block of all other wave types. A sine waveform has the appearence of a symmetrical "wobbly w" with nice rouded edges. A sine wave is also known as a "simple waveform", whereas all others are known as "complex" ones. The reasons for this is that a sine wave is the only kind of pure tone without harmonics (and can only be produced electronically). Suppossing that another sine wave of a different frequency is introduced, harmonics would then be produced, the waveform of the sum of these two waves would be more asymmetrical, and (as mentioned above) would be a "complex" waveform. Alternating Current takes the form of a pure sine wave.

Square Wave: - A Square Wave is a wave which is built from an infinite series of ever decreasing odd sine wave harmonics. It has a "periodic" (on-off) nature, and it is this which gives it its chacteristic square shape. Square waves are often used as test signals, as it can test a device over a wide range of frequencies simultaneously due to the harmonics mentioned above.

Sawtooth Wave: - So named as the shape of this wave (when pictured through an oscilloscope) resembles that of the jagged teeth of a saw. It differs from the Square wave described above in that it contains both even and odd harmonics (giving it a strident, somewhat aggressive quality).

"Wet" signal: - signal which has been processed in some way (by reverb, eq, or whatever). Opposite of "dry" signal.

Wide Field: - see Near Field.

Word / Word Clock: - In computing, a "word" is a piece of data which is small enough to be loaded into the Central Processing Units register in a single operation, the size of the word is dependant on how many bits the computers CPU may handle at one time. With modern PCs this is generally 32 bits, so here, a "word" will be 32 bits, or 4 bytes long.

A Word Clock is an essential part of any digital recording system, measuring digital time in terms of digital audio "word" which is a "sample" . In "home" digital recording setups, the word clock is often an embedded part of the digital datastream (the "S/PDIF" and "AES/EBU" interface standards are an example of this). However this can make the digital audio stream prone to "Jitter" (see above). More expensive professional systems however, tend to use a discrete word clocking system, utilizing the "BNC" standard connection. Here the time clock utilizes a square wave signal, which runs at the same sampling rate as the main audio signal.

Wow and Flutter: - More from the old days of tape machines, turntables etc than the modern, "digital" age. This is when slight variations in the speed of a tape transport, turntable motor etc creates an annoying "wobbly" variation in pitch. Generally, the "wow" part describes the effect created by slower variations in speed over a longer period, whereas "flutter" describes sharper variations over a shorter period of time.

XG (MIDI): - See MIDI.

XLR Connector: - Short for "X-tended Locking Round" A professional standard, three pin balanced connection system, originally developed by the ITT and Cannon corporations. It is a standard connection for microphones, and frequently used for much professional equipment which requires balanced inputs / outputs.

Y-Connector: - Where two connectors are fed into one connector of the same type, enabling a signal path to be split into two.

"Yellow Book" Standard: - Originally devloped by the Phillips and Sony corporations, and similar to the "Red Book" standard (see above). However it is slightly less strigent, in order to accomodate the CD ROM drives found in most Personal Computers.

Zenith: - See Azimuth (Alignment).

Zero Level: - The level of 0dBV. This is NOT the lowest level, but rather, it is (usually) the optimal maximum level for recording and broadcast purposes, getting the best signal to noise ratio without "going into the red", and the distortion that entails.

Zero Crossing Point: - Both sounds and electrical signals are primarily oscillations, and they oscillate around around an equilibrium or axis known as the "zero crossing point", where a negative signal crosses over into being a positive signal, or vice versa. It is also sometimes referred to as the "null point".

In recording / sampling / loops etc, the start and end points of an edit should conform to the zero crossing point of the signal, in order to avoid irritating "clicks" which are the result of two conflicting signal amplitudes (level of signal).