This glossary goes along with the syllabus for my two Digital Sound classes. I (always) have a bit of updating to do, so not everything will be in here right away, in the meantime you can consult whatis.com, ask.com, or any other of the many serchable dictionaries around.. These defs are intended to be helpful in the class context, so don't expect Noah Webster here, but hopefully they'll fill a few gaps in your jargonese. And Wikipedia is amazing.

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.WAV
The file extension for the "wave" format, originally developed for Windows. There was a time when you simply couldn't open one type of audio file unless you had a specific platform and software. Now it is a simple process to convert from one file type to another, using any of the standard audio or video apps.

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.WMA
Windows Media Audio, the more recent way to name a Windows Media file. see .asf. There's very little difference between the two, in fact you can usually rename the suffix with no ill effects. However, certain programs require either one or the other due to their specific scripting, so beware.  

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"0" DB (STANDARD REFERENCE LEVEL)
This setting on a mixing board or recording device means that you are set to receive the optimum sound level for that particular device. Any adjustments which you make to volume, either increasing or decreasing, should be made in reference to "0". One usually sets reference levels by sending a selection of sine waves at different frequencies at a known volume level into the system and setting the input to 0db. Then you know that you're getting the most accurate transfer possible from your source deck.

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1KHz
One KiloHertz, or one thousand cycles per second. This frequency is commonly used as a standard level setting tone.

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-10(dB)
The measurement of 'consumer' quality equipment to handle a nominal reference voltage level. Yields about .44V as opposed to professional gear (see +4dBu)which gives 1.74 or so.

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11025
rapidly becoming archaic, this is the lowest acceptable sampling rate for an uncompressed audio file, except in the case of samplers, where you can individually set rates for each sample. It only gives a fidelity of 5.5KHz, which is barely enough to capture the harmonics of speech, much less sibilants, etc. Approx phone quality. With advances in smart compression, it's rarely necessary to butcher your sound to that extent, in fact, you usually feed the compression algorithm your best quality sound, and let it make its own choices.

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128
2 to the 7th, or %(binary)10000000, a very good number to know...for one thing, it's the number of discrete values you can have in any midi data byte (except for pitchbend, which is double precision (16234 values).

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16BIT
the size of a single sample value in a "CD quality" recording. Since it can encompass a range from 0000000000000000 to 1111111111111111 (binary), that means it has a total range from 0 to 65535, making it analogous to the Windows "thousands of colors" setting, in terms of the resolution of the dynamics of the sound. This can be directly related to the Signal to Noise ratio, and about 96dB of dynamic range...(see http://www.faqs.org/docs/sp/sp-24.html )

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22050
This is the preferred sampling rate for multimedia applications, where disk space or upload time isn't as much of an issue. Most CD ROMS utilize this speed, as it gives a fidelity of up to 11kHz. On the Web and in space sensitive applications, the rate is often bumped down to 11025, which gives a fidelity of a mere 5kHz, but runs very smoothly. Thanks to MP3 compression, you can usually keep your source material at 44k or greater and let the compression handle the resampling.

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22255
This is the sampling rate preferred by Macintosh computers up through most of the Quadra series. Newer Macs have (finally) switched to the more standard 44100/22050 capability.

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256
2 to the 8th, or %(binary)100000000, a good number to know, since it's the number of values (including 0) that can be represented by a standard 8 bit byte.. beware though, the highest actual value is %11111111, or 255, so when you refer to the highest value in a particular byte or digital word, you generally describe it as "2 to the 8th minus 1", etc.

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31KBAUD
31 thousand binary audio bits per second. This is the rate of MIDI transmission between the synth and the midi interface or another synth. There is a 5% tolerance faster or slower than that, but the actual rate is closer to 31,250

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44K
short for 44 kiloHertz. Actually 44100Hz. This is the industry standard sampling rate for digital audio as it is found on audio CDs (redbook standard). This gives you an acceptably high fidelity recording, since frequencies of up to 22050 can be captured at that rate.

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+4(dB)
The nominal input level for a 'professional' audio device. The idea is that for a given input voltage, that's the amount of output (measured in dBu ('unloaded') you'll get. Compare to consumer level, which for the same input will only give you -10dBV, or ~.44V as opposed to 1.74.

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48K
or 48000 Hz. This is the sampling rate most commonly used by DAT recorders and DV cams.

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440Hz
Four Hundred and Forty cycles per second. Any vibration which changes at this speed will produce the tone of "A" above "middle C". This pitch is used in everything from audio calibration to the tuning of an orchestra before a concert.

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60 CYCLE HUM (GROUND HUM)
60 Cycle refers to the tone 60Hz, somewhere around a low B-flat. This is the speed at which alternating current flows out of your wall into anything you plug in. Thus, a 117 volt electric fan is being driven by 117 volts at 1.5 amps which changes its electrical charge 60 times every second. This is where the impetus to drive the fan comes from. All the fan needs is a motor, which is simply an electro-magnet suspended inside a metal coil. This energy is the same energy used in all facets of audio. The terrible 60 cycle hum arises when a loop is accidentally created within the circuit that allows that raw energy to bleed into the important portion of the audio channel. Since the rate of change is steady, you hear a warm, low pitched hum or buzz. It is usually easy to fix such a problem, but in a complicated studio setup the problem is often tracing down the origin of it. Simply making sure that whatever piece of equipment is causing the offending buzz is properly grounded solves the problem most times. Otherwise it could arise out of a mismatch of impedances, or even a short in the audio line. The more sensitive the device, the worse the hum is likely to be, for instance electric guitars, mics, vinyl turntables are typical culprits, and the cure is to run a wire from the sleeve (or sometimes the chassis) of the audio to the third prong of a wall socket, or even simply to the chassis of one of the devices which is properly grounded.

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65536
a good number to know, since its the number of values (incl. 0) that can be produced by a 16 bit system. This means that you can resolve the volume level of any audio signal digitized at 16bit, from it's quietest to it's loudest moment, into 65536 steps. Think of the way a screen draws a slanted line: the higher you raise the monitors resolution, the smoother the line looks. At a low resolution (8 bit color, for instance), the line looks like a staircase. In soujnd, bit depth plays a similar effect on the ear, with the 'jaggedness' of the 'line' analogous to the amount of distortion in the signal.

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A.C.
Alternating Current. The type of energy which comes out of your electrical socket., So-called because it continuously switches direction, from positive to negative and back. (see 60 cycle hum). Nicola Tesla is responsible for getting the U.S. to switch to a.c. from Edison's d.c. (direct current).

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ADC
analog-to-digital-convertor. The part of a digital recording device that converts the incoming analog voltages into discrete digital information. Technically it's a combination of an anti-aliasing filter (see), and a series of gates. The more gates (bits) the better quality audio you can digitize.

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ACTIVE SENSING
Since MIDI is full duplex (simultaneous two-way communication), a constant stream of binary data in a "holding pattern" is always present on the line as soon as the MIDI device is powered up. This stream is changed momentarily by anything which happens to the instrument, such as a key being pressed, patch change, sys ex command, etc. Normally you run the instrument in this 'asynchronous' mode. In a live performance, things can happen which sometimes result in notes not turning off, pedals getting stuck in the on position, etc. When Active Sensing is enabled, the synth includes a special packet of information periodically in the midi stream. If the listening device stops getting that packet (because of stuck notes, etc.) then it automatically turns off notes coming from the offending synth, resets the controllers, etc.

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ADPCM
A lossy form of compression once favored by the wintel platform, until the advent of mp3, which seems to be replacing just about everything. ADPCM was one of the first schemes which let you specify different levels of compression depending on application.

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AES/EBU
"Audio Engineering Society/ European Broadcast Union", the standard for digital connections between devices most widely used in professional applications. You can recognize an AES/EBU connection by its' XLR xonnectors, one for output and one for input. The splitting of information into seperate left & right channels is handled in the digital stream, hence only a single cable is needed.

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AFTER TOUCH
also known as poly or channel key pressure. The capability in a midi controller to allow you to apply pressure to a key after it's been pressed, supplying more musical expression in the form of modulation, etc.

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AIFF
Audio Interchange File Format. (according to some, Apple Interchange File Format) One of the many ways in which digital sound is organized as a computer file for transport between different systems and platforms. This format works particularly well for the Macintosh, while the .WAV format is preferred by IBM machines.Nowadays though, any application worth its salt should be able to open either regardless of platform.

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ALIASING (FOLDOVER)
This is a phenomenon which arises when you try to digitally record any frequency which is higher than 1/2 the sampling rate( the Nyquist frequency) that you're using. The digital system will go right ahead and sample the waveform as best it can, but will return a value which is the difference between 1/2 the sampling rate and the actual frequency. In other words, a completely new, and probably unrelated, pitch will be produced by the digital system. This is prevented through the use of an anti-aliasing filter, through which the sound is passed before it is sampled. The filter cuts out any frequencies above the Nyquist.

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AMPLIFIER
an electronic device for controlling the volume or loudness of a sound, or for increasing the strength of an electrical signal.

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AMPLITUDE
Usually referred to as the 'volume' or 'loudness' of a sound. Amplitude is the distance between the 'peak' and the 'trough' in the waveform of a sound, and is measured moment to moment. You can also take an average, sometimes referred to as "root mean square" (RMS).

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ANALOG
is generally used as a term to diametrically oppose the term 'digital'. An analog signal has an unbroken connection to its' source, unlike digital, where the source must first be broken into discrete units. In audio, analog means 'continuous', uninterrupted. An example of an analog device would be a typical sine wave oscillator in a Moog synth. Another would be a conventional cassette recorder.

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ANGLE OF ROTATION
is a way of mathematically expressing the frequency of a wave or harmonic as an angle created by the rotation of a point around a unit circle.

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ARM
Most digital recorders have built in foolproofs against accidentally trigering a recording. For instance, in a Zoom recorder yo hve to hit the record button twice; in Pro Tools, Logic, you have to record enable a track, hit a record arm button, then hit play to initiate the transport. On a beta machine you have to unprotect the tape, then hit play while pressing record, etc. etc. Arm simply means to do whatever you need to to prepare your tool for recording.

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BNR
Broadband Noise Reduction. Originally developed by Digidesign, this is a very useful tool for intelligently removing noise from a preexisting recording. It is a very fine resolution multiband filter which is tuned to the frequencies contained in a sample of the unwanted noise. The filter is then applied to the entier recording, esentially 'lifting out' the noise component. With proper adjustment, this one plugin has saved many a hopeless audio file. Now pretty much everybody makes them, for the whole range of prices (including free).

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BOUNCING TRACKS
The process of digitally transferring a multi-track session to a new mono or stereo file, either as a mastering step, or to free up tracks for more input.

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BREAKPOINT
A user defined point on a graphic 'rubber band' type onscreen control.

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BUFFER~
MSP object which allows you to allocate a ram based table for temporary storage of a sound. Much faster then direct to disk, crucial for any operation where realtime waveform manipulation is desired.

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BYTE
a set of eight bits. Can express a range of numbers from 0 (00000000) to 255 (11111111).

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  CAHILL, THADDEUS
Inventor of the Telharmonium (see @ emf.org). An interesting blurb (and pic) can be found here

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CAPACITANCE
The tendency (unwanted) of a wire or conducting device to buile up static electricity. This can cause noise and pops in a recording. One of the reasons why you can only run audio cable a finite distance without extra electronics to take care of the 'baggage'.

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CARDIOID
A common mic sensitivity pattern which, in cross-section, looks like a heart shape. Actually it's more like a balloon pressed against the head of the mic. The pattern can be varied by the construction and electronics of the mic, into variations such as hypercardioid,supercardioid , etc.

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CHANNEL
Specifically, the second nybble of a status byte (in the set of midi messages termed "channel messages") which assigns a MIDI event to a specific destination. MIDI supports 16 channels which is extended through the use of "ports" and virtual decives.

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CHANNEL MESSAGE
The most common type of MIDI message, ranges from hex 9(0-F) to E(0-F). Governs such things as playing notes, changing volume, bending pitch, etc. Contrast with System Message, which governs behaviour of an entire synth, sequencer, etc.

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CHORUSING
a technique used in "fattening up" a sound, by taking the original sound, digitally reproducing it, then detuning the copy slightly. The effect when the two are then played together is of two different sources (singers, instruments, etc.) playing the same note.

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CLICK TRACK
an audio signal used in a sequencer to provide the performer with the beat/tempo for recording purposes. While the original click was just a dry, percussive sound, nowadays you often also have spoken cues embedded into the click track as well, for extra precision.

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CLIPBOARD
A temporary storage area in the ram of the computer where items you cut or copy are kept pending your pasting them elsewhere.

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CLOCK SEQUENCER
Part of the gear of a typical modular synthesizer of the 70's. Precursor to the digital sequencers used in midi, this device would supply an array of voltages that could be 'tuned' by the user in a series. Listen to On The Run from Dark Side of the Moon by Pink Floyd, for a very nice sequencer segment. Also, Touch by Morton Subotnick.

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COAXIAL
a cable which uses two conductors, one in the form of a cylindrical "shield" which surrounds the other all along the length of the wire. Used in unbalanced audio systems and video cable.

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CODEC
short for COder-DECoder. A two sided algorithm which applies compression to a data stream as it comes in, then applies decompression to it on the way out. A codec may be hardware or software based, and may be either lossy (information in the original file is lost in the compression process, such as Realaudio, mp3, etc.) or non-lossy (information in the decoding process is completely restored to the original state, such as Stuffit, .hqx, winzip, etc.) Codecs are most important in video, where the movement of a vast amount of data is necessary each moment. MPEG is a very popular example, as well as Sorenson.

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COLD
A 'plumber's term' for the negative part of an audio connection, typically black or white in a siple conection, black, white or clear in a more complex cable.

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COMBI MODE
In the Korg M1 synthesizer, "combi" is their not-so-standard synonym for the multitimbral mode.

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COMPRESSION(1)
The effect whereby the force emanating from a sound-producing body causes the air to 'bunch up' as molecules collide. This creates 'standing waves' which allow the sound to carry for long distances before it is eventually dissipated.

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  COMPRESSION(2)
Any algorithm designed to reduce the file size of a digital audio stream. There are two versions of compression: lossy, such as realaudio, mp3, etc., where part of the audio is altered and/or disposed of, and non-lossy, where the audio is temporarily compressed, then reconstituted by the software on the receiving end.

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COMPRESSION(3)
The process of reducing the dynamic range of a recording so it will sound fuller in a lower bandwidth environment, e.g., radio, t.v., the web, all of which have limited dynamic range.  

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CONDUCTOR
Any part of an electrical circuit which allows the flow of electricity. Opposite of INSULATOR.

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CONDENSOR
a type of mic which contains its own built-in electronics to help increase the frequency and dynamic response, lower impedence, etc. Opposite of dynamic mic.

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CONTINUOUS CONTROLLER
is a complete misnomer. In MIDI nothing is really continuous, so the trick is to fool the ear into thinking that things such as a smooth change in volume of pitch is really that. Such is the purpose of continuous controller messages. When you send out the same message in a stream with slight increments in each one, the ear is pretty easily fooled into hearing it as a continuous event. Refers to a command used in MIDI to supply note-on, volume, controller signals into a tone generator. Controllers may be keyboards, wind devices, guitars, villins, and a host of more esoteric forms such as infrared sensors. The thing to remember is that if you're buying a MIDI controller it doesn't necessarily mean that sound actually comes with it! Hex B(0-9), with the first data byte naming the controller number and the second specifying how what to change to.

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COPY
to make a duplicate of an audio region on the clipboard.

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COS
the cosine function. Imagine a dot moving counterclockwise around the perimeter of a circle (usually represented with a radius of 1). The cosine is the position at the intersection of the horizontal and vertical lines that would stretch from the dot to the center of the circle with respect to the horizontal, that is to say, the ratio between the length of the two lines thus made.
http://mathworld.wolfram.com/Cosine.html
All sound can be shown to be made up of cosines and sines at different frequencies, phases and amplitudes.

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COUNTOFF
"ah one and ah two and ah three and ah..." Typically used in a sequencer in conjunction with the click track

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CPS
Cycles Per Second, another measurement of frequency, same as Hertz.

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CROSSFADE
a method of altering the spliced areas of two files so that they blend better. A portion of the beginning of the righthand file is faded into a portion of the end of the lefthand file. There are many variations on the type of fade, usually accomplished through a graphic interface.

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CSOUND
An improvement over the earlier lingua franca for music synthesis, Fortran. CSound uses the C language and a score/orchestra file structure to compile non realtime tables and algorithms into sound files, though a lot of realtime work is currently being done as well.

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CURRENT
Measurement of electrical 'flow' (symbol I). Basically the speed of flow, or voltage/time.

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CUT
to move audio to the clipboard, removing it from the source area.

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CYCLE
A single, complete pass through the shape of a periodic wave, usually containing information both above and below the zero line. A cycle is made up of 360 degrees.

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CYCLE~
A MAX/MSP sine wave generator

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DAC
Digital-to-analog-convertor. The output end of a digital recording device. Like the ADC (see), the DAC is also a combination of devices, including a filter. Like the ADC, the DAC's filter is also a lowpass, only in this case, it serves to smooth out the tiny jumps in amplitude which aare unavoidable when you reconstitute a digitally produced signal.

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DAT
Digital Audio Tape, an industry standard for digitally capturing audio. DAT uses a rotating head assembly like a VCR to create a very stable digital transfer onto a slow-moving tape.

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DATA BYTE
second and third bytes of a midi channel message. while the status byte esentially tells the device what to do, it is the data byte that says 'to what' and 'how much'.

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DAVIDOVSKY, MARIO
Composer, Listen to any of his Synchronisms for various instruments and electronic sound.

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D.C.
Direct Current. An electrical flow which goes in one direction only, such as that produced by a battery.

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DECAY
The second phase of a sound's envelope, where the initial amplitude 'plateau' begins to die away to some sustaining level. Can vary in time from milliseconds to seconds.

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DECIBEL
The standard unit for measurement of the intensity of a sound, literally a tenth of a Bel. dB units function on a logarithmic scale much like the human ear itself. Because we are sensitive to changes in amplitude of millionths in terms of the actual change in sound pressure level we can't use a simple arithmetic scale to measure such changes, hence the need for a logarithmic one, where an exponential change can be easily plotted on a chart, measured on a mixing board slider, etc. "0" on the dB way of things means the threshold of hearing, where around 180 dB is about as much as a person can stand without getting new eardrums. In actuality, 180 dB is millions of times louder than 0 dB.

Here's an excellent exposition.

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DEFAULT PATCH
A helpful feature in sequencing software which ensures that your MIDI file will have each track automatically call the appropriate patch on your MIDI synth. In Performer for instance, you set the default patch simply by selecting the name of the desired patch in a column in the tracks window. Unfortunately, that default is typically limited to the software in which you set it, that is, if you then export a standard midi file, the default patch stays behind. So it's still a better idea to explicitly set the patch in the track itself.

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DESTRUCTIVE
refers to audio editing in which permanent changes are made to the original audio file (media). Programs such as Peak and SoundForge do destructive editing primarily, while those like ProTools are Non Destructive by design.

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DIGITAL
refers to information which has been quantized into discrete numerical values. Virtually anything can be digitized. In audio, the digital signal contains changes in amplitude over time which represents a captured audio waveform.

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DIGITAL DELAY
The use of digital equipment to produce "echo" in a sound. Analogous to the Echoplex of yesteryear, a device much loved and much overused by many guitarists.

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DIGITAL SYNC
When recording from one digital device to another it's usually desirable to 'slave' the input machine to the output to prevent timing errors, dropouts etc. This is referred to as digital sync, as opposed to internal sync, where each device runs under its own clock.

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DIGITIZE
To convert something from the analog world into the digital domain, through an ADC (see).

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DIN
the five pin plug/jack used in all midi devices. Only two of the five pins (three counting ground) are currently used.

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DINR
Digidesign Intelligent Noise Reduction...a great gift to digital recording (well, not exactly "gift": costs $1000). It is a plug in that you use to analyze a portion of noise in a recording, then lift out all the noise, leaving all the good stuff behind. Sonic Foundry makes an excellent version of the same for ActiveX, and all the plugin manufacturers are coming out with their own, Waves, for instance. <rant>It's too bad when companies charge for something based on how desperately they think people need it, rather than on the amount of work that went into making it.

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DISTORTION
is a (usually) undesirable quality in sound which has been recorded or processed beyond the limits of the system attempting to do so. It literally takes the smooth, sinusoidal shapes of the sound waves as they reach the limit of the system and chops off anything over the limit, so you end up with a lot of square waves where you should have sines. As a result a huge amount of erroneous harmonic information is added to the sound, and the original balance is destroyed. For some people this is a good thing.

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DITHERING
A feature of digital editing software which alleviated some of the unwanted artifacts caused by digital manipulation by adding noise (believe it or not) to the soundfile as it's processed. The noise is much smoother than the lowest order bits of the soundfile that would otherwise be left behind after processing, so is much harder to detect by the ear, giving a smoother result.

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DRAW
a nifty feature in software such as pro tools which allows you to sculpt your own waveforms with a pencil tool. Most useful for smoothing out digital glitches and awkward splices.

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DSP
Digital Signal Processing. Either refers to the process of altering sound digitally, or to the actual hardware used in digital recording and processing. Computers have DSP cards which are dedicated to working with audio, thereby freeing up the CPU for other things.

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DURATION
The length of an event. In a MIDI sequencer, duration may be specified in SMPTE (HH:MM:SS:FF), 'realtime' (MM:SS:1/100ss), or in musical beats and divisions of a beat.

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DYNAMIC
refers to changes in the loudness of sound, its range is measured in dB. The better the recording, the higher the dynamic range. Poor is in the 60s, good is in the 80s, digital is in the 100s, all mediated of course by the skill of the recordist.

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  ECHO(1)
also known as Digital Delay..a dsp function which allows you to create a reiteration of a selection of audio, complete with decay, feedback, and often several other programmable tweaks such as delay time.

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ECHO(2)
to cycle an input through its destination output so that it appears again at the input. Originally used in modems as a way of making sure that what you types was what got to the network. Currently used in MIDI to route signhals to programmed destinations.

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EDIT
Digital synthesizers, being computers, tend to be made by engineers who are very conscious of data protection. Therefore you usually have to put the device into an 'edit' mode before you are allowed to make changes which will permanently alter the patches it contains. A special memory buffer is usually reserved for this, so that even when you're editing you can't really ditch the previous patch until you actually 'save', thus replacing the patch with the edit buffer contents.

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ELECTRICAL FIELD
Part of the 'electromagnetic spectrum' surrounding a certain thing. Audio devices must be shielded from stray electromagnetic radiation, which can degrade the signal.

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ENCAPSULATION
the use of sub patchers in MAX to improve the logical flow within a patcher.

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ENVELOPE
The 'shape' of a sound. An envelope is the profile of the amplitude curve created by a given sound, and is conventionally broken into four basic stages: attack, decay, sustain and release.

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ENVELOPE GENERATOR
A device used in conjunction with a voltage controlled amplifier or filter to provide the above mentioned shape to the desired parameter of a sound. Typically has four stages, ATTACK (A), DECAY (D), SUSTAIN (S), RELEASE (R), or ADSR. Nowadays computer generated envelopes can have pretty much as many levels and timepoints as you want.

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EQ (EQUALIZATION)
The process of emphasizing or reducing a certain range of frequencies in a sound. EQ controls can either be found as a part of a mixing board, or as a separate device. EQ is a specific type of filtering, and is usually divided into BANDS of frequencies. There is a HIGH range, a MID range and a LOW range, with inbetween divisions, depending on the quality (and cost) of the equipment. A very powerful form of such a device is known as PARAMETRIC EQ, in which the frequancy ranges can be manipulated so precisely that you can filter out individual pitches.

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EVENT
either a single occurrence of something (a bit flipping from 0 to 1, for instance), or a group of related phenomena which may be conveniently grouped together, usually in a time-based frame. Thus, a 'note' is an event which contains elements of frequency, timbre, amplitude, duration, etc. In electronic music and MIDI, it's important to be able to identify the individual elements which make up a single sonic event.

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EVENT LIST
One of the editing modes in a MIDI sequencer. The event list is the most basic, simply giving you a chronological list of each MIDI event on that track, listing note number, velocity, duration, controller numbers and values, etc.

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EXPANSION
Opposite of compression: to increase the dynamic range of a soundfile, usually with the purpose of lowering the noise floor. Softer version of the noise gate.

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    FFT
FastFourierTransform, a computer algorithm which allows you to analyze a finite moment of sound for pitch content. MSP has an fft~ object for that purpose. Basically, the selection of sound is split up into 'windows', and each is scanned for periodicity. The function returns pairs of amplitude and phase numbers.

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FILTER
A class of electronic device which is used to affect the 'color' of a sound, by specifically affecting the amplitude of only a certain portion of the frequency content of the sound. By contrast, an amplifier affects the entire sound. Typical varieties are (see) lo pass, hi pass, band pass, band reject, peak-notch, lo shelf, hi shelf, octave, graphic eq.

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FLANGING
a musical effect created by taking a sound, making a copy of it, then playing back both sounds while shifting one of them in time, usually by a very small amount. Increase the delay and you have digital delay. With flanging, you get a metallic, sweeping effect in the sound.

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FLOAT
a floating point number, the computer's way of dealing with decimals. Contrast with integer.

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FM SYNTHESIS
Frequency Modulation. A technique for creating interesting musical timbres pioneered by John Chowning in the 80's. You can change the harmonic spectrum of a CARRIER signal by modulating its frequency with another signal. When the two signals are both members of the same harmonic series, side bands are produced which emulate the harmonic sperad found in nature in acoustic instruments.

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FORMAT 0
a standard midi file which compress all data into a single track. Since a track is an arbitrary partition anyway, it has little effect on the way the file is seen by most external midi file players.

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FORMAT 1
a standard midi file which maintains the channel/track relationships inhereted from the sequencer file that created it.

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FREEMIDI
Mark of the Unicorn's answer to Opcode's "Open Music System" (formerly Opcode Midi System), which is the system level software that manages the flow of MIDI information between your applications and hardware. It would be really nice if one of them would give up and totally tool their software for one system only. Maybe they'll even merge into one company someday and save us all the hassle of trying to deal with the petty incompatibilities of their system software (sure they will...seen any flying monkies?).

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FREQUENCY
A measurement of change over time. Frequency can describe the periodic motion of anything from the Earth around the Sun (1 revolution per year), a clock ticking off seconds (1 tick per second), or a musical tone (440 cycles per second, for instance)

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FREQUENCY RESPONSE
refers to the behaviour in terms of amplitude of a device as measured across a range of frequencies. The ideal device would produce the same amplitude for any frequency it received, but this is never the case. It is instead an absolute against which devices can be measured. Flat frequency response refers to this goal, and the flatness of a device is an indication of its quality.

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FULL DUPLEX
a communications system in which a signal can flow freely in both directions at the same time, a telephone for instance. MIDI is full duplex. A walkie-talkie is only half duplex (two way communication..not at the same time).

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FUNDAMENTAL
The part of a sonic vibration which oscillates at the ratio of 1/1. Also known as the first harmonic.

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GAIN
Usually refers to the volume level of sound as it first comes into a device such as an amp or mixer. Setting the initial gain is necessary to avoid distortion or unnecessarily high noise levels in the audio even before it is raised and lowered with the normal volume controls. In other words, if the gain is set too high, no amount of fiddling with the other volume controls will prevent the sound from being distorted. Likewise, if the gain is set too low, then cranking up the volume in the mixer will add lots of noise into the sound as it brings it up.

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GAIN REDUCTION
When you employ compression or L1 peak limiting, there comes a point where the system has to attenuate the signal to avoid distortion. It usually appears as an opposing display to the vu meters, as the input levels go over a certain threshold, you can see the gain reduction kick in and start registering in the opposite direction. The louder the signal, the more gain reduction is employed. This allows you to raise the quieter portion of the signal while backing off the level of the loud part.

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GENERAL MIDI
an extension to the midi specification which seeks to standardize certain areas which are considered to be problems in the original midi soec, namely the way in which sounds (programs, patches) in a given synth are stored and named. In the GM convention, sounds are stored in a bank of 128 programs, which is divided into 8 groups that encompass the basic classes of musical instruments, e.g., the first 8 sounds are piano keyboard type sounds, the next 8 pitched percussion, and so on. Manufacturers of synths are free to create unique sounds for their machines, provided that they roughly fall within those designations, in order to be considered truly general midi. The chief advantage is in portability: you can create a midi file on one platform, and open and play it on another, with some degree of consistency in the sound.

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Global
Refers to a mode available on typical MIDI devices which place the device in 'live performance' mode. Typically this reconfigures the keyboard so that it will respond on a single channel, instead of all 16, for instance. If you want to use your midi synth as a multitimbral workstation, stay out of global mode!

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GATE
To "gate" as a verb means to "hold open". A gate therefore is a device which "holds open" the flow of a signal in some way. A noise gate, for instance, allows an audio signal to pass through as long as it is over a certain loudness. The moment it falls below that loudness, the gate "shuts", cutting off the sound clean. As you can guess, this might be used to either remove background noise, or more musically, to give an extra punch to short sounds.

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GRANULAR SYNTHESIS
A synthesis method pioneered by Curtis Rhoads and others, which treats sound as a collection of tiny 'atoms' or 'grains'. By altering the timing, envelope, density, shape, etc., of the grains, one can produce a wide variety of timbral effects.

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GRAPHIC EDIT
Also known as piano roll notation. Displays note-on and other data on a graph, height represents pitch, length represents duration. MIDI can be edited by moving it around on the graph, stretching note icons to lengthen them, etc.

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GRAIN~
msp object which does granular synthesis. A small 'wavelet' may be designated to be a 'grain', which becomes a reiterative element in a larger sound. As one changes parameters of the grain, the overall sound changes.

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GRAPHIC EQUALIZER
A bank of filters which may be used to independently boost or cut several ranges of frequencies in a sound. The filters are arranged side by side in a bank, and divide the frequency spectrum into many bands, separated in octaves, half or third octaves, or fixed frequency divisions. Often used to compensate for weaknesses in a particular sound system or acoustic space.

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  GRID
Like most graphic programs, which allow a graphic to be constrained to rules on the screen, sound clips may be constrained to time divisions. ProTools has a grid mode which allows you to adjust regions of sound in selectable increments. Digital Performer allows you to use a quantize grid when snapping notes to regular rhythmic spots, adjustable to most note values.

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  GROOVE~
MSP object which serves as a loop player for various buffer~s.

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GROUP
Also called sub-group; an extra set of assignable outputs in the output stage of a mixer. It simply gives you an extra way of getting audio out to a specific place so as not to conflict with your main outs. A typical use of sub groups would be to send your stereo mix to a device which required its own independent level setting apart from the master mix. Affecting leels on the main mix would not affect the settings on your sub gtoup.

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GTE
"go to end"

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GTZ
"go to zero (start)"

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HALF DUPLEX
Bi-directional communication, not simultaneous. A walkie-talkie, for instance.

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HARMONIC SERIES
An ascending series of multiples of a fundamental frequency. The harmonic series gives us such interesting phenomena as the major triad. As the frequency of a given tone is multiplied by increasing integers (1,2,3...) the resulting tones stack up in this series: f, 2f, 3f..., which give the resulting intervals of the octave, fifth, fourth, third. etc. This series occurs in nature and is a part of all musical instruments and most sound related phenomena.

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HEADER
The part of a digital sound file which stores the basic info that tells the computer how to treat the file, e.g., what sampling rate, bit-depth, format, etc.

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HEAD ROOM
In analog recording, a certain amount of leeway may be allowed in the amount of signal allowed into a recording. The rule of thumb is to put as much information on the tape as possible without distortion, thereby minimizing background hiss. Analog record heads can usually take somewhat more "juice" than you'd think from watching the vu-meters. Thus we have terms relating to the behaviour of the meters themselves. One such term is "bouncing" the needle. This occurs when the needle (or led nowdays) briefly goes far into the "red zone" of the meter. This is unavoidable in music which contains short, high amplitude sounds such as a drum kit. An analog machine can take this sort of abuse quite well. The meter behaviour which is death to most any recording is called "pinning", where the led or needle hits hard against the right (or top) and stays there. The head room refers to the amount of bounce that can occur before distortion sets in. Digital systems generally do not have headroom unless the system is intentionally calibrated that way. In fact, the "0" on the vu meter of a DAT machine is generally the absolute maximum before distortion. And digital distortion is not a pretty thing.

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HENRY, PIERRE
One of the pioneers of Musique Concrete. Listen to his Variations Pour Une Porte et un Soupir.
HERTZ
Abbreviated Hz, the measurement of frequency in cycles/second, named after Heinrich Hertz.

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HEX
a number represented in the hexadecimal (base 16) numbering system. Very useful in midi, because it is much closer it nature to base 2, which is crucial in understanding and creating midi messages. Uses the digits 0-9, then A-F to represent in single digits the values 10-15. Another advantage is that you can represent large numbers with fewer digits than you could in base 10.

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HI SHELF
A variant of the lopass filter, in which the righthand portion of the frequency range can be either cut or boosted at the cutoff frequency.

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HI PASS FILTER (HPF)
This filter is used to remove low frequencies from a sound. As the cutoff point is raised (by turning a pot clockwise, or raising a slider), low frequencies are reduced to zero amplitude. This is sometimes used to get rid of hums in recordings which are being processed for lower bandwidth applications, since low frequencies are lost in the process anyway. More often, hums are removed using Digidesign's Hum Removal software.

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HI-Z
Another term for Hi impedance.

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HOT
A 'plumbers term' for the positive (signal) wire in a connection. Typically the 'red' one in a simple wiring scheme, or the colored ones in a more complex cable.

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HUMANIZE
Opposite of quantize. In MIDI, allows one to randomize various parameters of previously recorded midi data, to reinject a more human feel. Also makes a good algorithmic composition tool.

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HYPERCARDIOID
A 'squeezed' heart-shaped sensitivity field for a microphone. Sometimes referred to as a 'shotgun' mic, this microphone picks up a narrow field of sound from a great distance. When used with a dish, such mics are routinely used for surveillance.

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IFFT
InverseFastFourierTransform. The method by which the amplitude/phase pair of numbers extracted by the FFT is reconverted back into instantaneous amplitudes. In MAX, one can analyze a sound using FFT, process the data, then reconstitute the sound ('resynthesize') again.

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IMA4
A digital compression technique brought to you by Apple. Gives very good results on 16 bit aiff audio files and reduces the file size by a factor of 4:1. Shareware such as Sound Converter gives you the ability to save with that speck, as do the latest releases of the usual programs.

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IMPEDANCE
The resistance of an audio system to the flow of (alternating) current. There are two categories: high impedance devices are consumer grade appliances such as cassette decks, tuners, CD players, etc. Low impedance devices are generally more costly to make, and are used for professional applications. Balanced devices are generally low impedance, unbalanced ones are high.Like resistance, impedance is measured in Ohms. Typical low impedance (Lo-z) might be 600 Ohms, Hi-z might be around 2000.

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IN
the port on a midi device which expects to receive information.

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INLET
topside of a MAX object, admits incoming data.

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INPUT
The part of an audio device which expects an incoming electrical signal from somewhere else. Inputs are generally governed by impedence (see above), either high or low.

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INPUT STAGE
The section of a mixing board that contains the many channels to be mixed. A typical channel in an input stage has controls for asignment, muting, pan,eq, aux sends, and gain control. A chanel might take only line level or may also have a preamp built in (in which case there would be a trim control as well as a gain).

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INSTRUMENT
In sampler context, an instrument is a collection of samples which have been mapped onto a keyboard. Typically, functions such as modulation, envelopes, reverb, etc., are added to the instrument in the sampler software.

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INSTANTANEOUS AMPLITUDE
Our perception of sound derives largely from our tendency to blur a series of rapid events in time into a cohesive whole. As a result we often have trouble conceiving of sound s a series of individual eents. Yet when you digitize omething, you are breaking up the continuous stream of information into discrete time/amplitude pairs. Any one of these represents the instantaneous amplitude of the sound at that moment in time. It doesn't mean a lot out of context, since you don't get sound till you reassemble all the amplitudes together. However, a whole world of change can occur between the analysis and resynthesis of a sound.

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INTEGER
a whole number. MIDI uses integers strictly.

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INTERFACE
that which allows one device to understand/talk to another; hardware, software, or a combination of both.

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INVERSION
A mirror image of something. In music, an inversion of C D E would be C Bb Ab (what went up now goes down). Inversion is a powerful compositional tool and most MIDI sequencers allow you to perform inversion on midi data.

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JACK
a.k.a. "socket", a jack is a recepticle into which a plug goes. The name of the jack matches the name of the plug, e.g., an RCA plug goes into an RCA jack. Plugs are sometimes configured as recepticles (with holes instead of pins), and are then referred to as "female" plugs.

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  KEY MAP
the way in which a sample or collection of samples is spread across a virtual keyboard. Each sample is assigned a note range and a root key (the key at which the original pitch of the sample will sound).

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KEY VELOCITY
The speed at which a note-on command is produced, e.g., the speed that a key goes down on a keyboard. Usually implemented as a volume/timbre combination control on a typical MIDI synth.

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  LATCH
a digital switch that stores a value until refreshed.

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LAVALIER (LAV)
A lapel mic, any mic esigned to be work inconspicuously on the body, available in both wired and wireless versions.

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LEVEL
The volume of a sound, as it can be controlled by some device such as a mixer, tape input, etc.

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LIBRARY
an alternative method of collecting patches in the computer. Programs such as Unisyn and the Galaxy Editor/Librarian allow you to gather a bank of sounds via sysEx, then organize them alpahbetically in any way you like. Such is a library.

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  LINEAR
If a one to one correspondance between the input and output of a device exists, it's said to be linear. This is desirable, just like flatness in terms of frequency. Cheak devices tend to have spots that are non-linear..that is, you put in a little, they give back way too much, or vice versa.

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LINE LEVEL
a term for the 'operating' voltage levels that will allow an electronic system to operate at peak efficiency. A properly pre-amplified signal (from a mic, for instance) will be brought up to line level, at which point it can 'play' with other signals at the proper strength level without introducing noise or distortion. Cassette decks, DATs, DV cams, synthesizers, computers all typically produce a line level output.

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LIST
A MAX feature which allows you to send values in a group as opposed to one by one.

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LOCAL CONTROL
one of the trickier things a traditionally trained musician has to get used to is the possibility that, in a midi keyboard situation, the keyboard may or may not be able to produce sound. The best controller keyboards, in fact, usually don't produce sound, but rather server as high quality 'dummy' keyboards, with the manufacturers devoting themselves to making the thing feel as much as possible like a real piano, with weighted keys, etc. The sound on the other hand is produced by a Tone Generator. This may be incorporated into the keyboard, but it just as well may not. In a midi studio, this becomes an important consideration. If you have a bunch of gear, you generally only want to hear a selected tone generator (t.g.) at a time, so there needs to be a way of disconnecting any sound producing capability of the keyboard from it's midi controler portion, lest you always hear it layered on top of everything else. So, local control means that the midi signal is routed both to the midi out port on the synth and the internal t.g.

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LOOKUP (TABLE)
an array of values intended to be used for efficient manipulation of an audio signal. In a typical digital synth for instance, the firmware contains lookup tables for several varieties of sounds, from simple sine shapes to complex samples. It is simple for the player part of the synth to find the table, repetitively scan through it, while applying other process to the digital info which emerges.

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LO PASS FILTER(LPF)
A filter used for removing high frequencies from a sound. As the cutoff point of the filter is rolled back (usually by turning a pot counterclockwise, or pulling down a slider), any frequencies above the cutoff point will be reduced to zero amplitude. This is useful in removing wideband hiss, though now one usually turns to intelligent noise reduction for that purpose.

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LO SHELF
a variant of the hipass filter, in which the left part of the freq range can be either cut or boosted at the cutoff frequency.

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LO-Z
Another term for Low impedance (see IMPEDANCE)

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lsb
least significant bit: the lowest valued (rightmost) bit (digit) of a binary number. In base 10, in the number 13, 3 would be analogous to the lsb.

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LSB
least significant byte: the lowest valued (rightmost) byte of a binary number.In some midi messages, such as pitch bend, the two data bytes are arranged as LSB MSB, with the fine tuning and course tuning set to each, respectively

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  MAIN
on a mixer, refers to the master stereo outputs, usually the final destination of a mix.

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MARKER
A visual "tag" that you put in a file, generally chronologically. Markers may be named and provide shortcuts for navigating around the file.  

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MATRIX
a method of organizing complex information, using rows and columns (and depth of same), where a given bit of data can be set or retrieved by specifying the x,y and z depth in the matrix. In Max, matrices are used to store video information for use with jitter objects. The x and y positions will typically correspond to the pixel location in a display window, while the z depth will specify the 'plane', analogous to a color separation in printing, e.g., red, green, blue, or alpha (transparency)  

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MAX
A graphical programming environment currently developed by Cycling74.com. Max was originally conceived to address limitations in the type of software that was being created for MIDI, by allowing a much greater degree of freedom on the part of the artist to put together data structures and send messages between them. Since its appearance in the 80's, Max has added extensive DSP capability (MSP) and now live video processing (Jitter). It is (IMHOP) the single most important piece of software that an electronically oriented artist should learn.

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MERGE
The ability to insert data from one track into another without erasing the what's already on the latter.

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METAFILE
a 'dummy' file used to point to actual audio or video material. Metafiles are used for security purposes: you put the metafile on your html page, which gives the browser the ability to find the underlying material and play it, but protects the original material from being copied or downloaded. It also allows the actual material to reside on a different server to optimize streaming performance.

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MESSAGE
a packet of midi data, consisting of a status byte, folowed by one or two data bytes, depending on which status.

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METER
The regular division of time in music. Tells what note value gets a "beat" (or pulse), and how many of those values are to be organized into a "measure".

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METRONOME
audible click for the purpose of keeping tempo. Also an object in MAX (metro) which provides a steady pulse.

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MIC LEVEL
The energy level produced by a 'weak' audio source, such as a phonograph needle, microphone, electric guitar, or any source which is not pre-amplified. Typically measured in microvolts. A mixing board will usually have a few inputs dedicated to mic level devices, and it's important to distinguish them from the line level inputs.

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MIDI
Musical Instrument Digital Interface. Standard communications tool for all brands of synthesizers. Serial communications protocol, full duplex, 31.25Kbaud. Eight bit word. Each message consists of a status (command) byte followed by one or two data bytes.

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MIDI MONITOR
Window in a sequencer which displays incoming midi data in realtime.

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MONO
The mode which only allows a synth to play one note at a time.

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  mp3
MPEG Layer 3, a very successful codec for compressing and delivering audio While it is 'lossy', it does a very good job of keeping the parts of the audio that the ear tunes into and discarding the rest. It is the codec of choice for export from Flash, and for transmitting music and audio via the web. Developed by the Fraunhoeffer Institute, and subsequently very aggressively marketed, putting a lot of very creative people on the war path towards replacing it with an open source alternative (ogg vorbis).

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msb
Most Significant Bit. Leftmost bit in a binary number. Carries the highest power of the base, thus is most significant.

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MSB
Most Significant Byte. Leftmost byte in a binary number. See LSB above.

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MIDI
Musical Instrument Digital Interface, the de facto standard for simple communication between all makes and models of digital synths, via a 31Kbaud serial circuit. MIDI is both the hardware circuitry that facilitates the communication as well as the low level language itself.

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MIDI NOTE
A multi byte MIDI message which contains a status byte (9), channel number (0 - F hexadecimal), note number (0-7F) and velocity (0-7F).

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MODE
a configuration in a midi synth which determines how it will respond to incoming midi messages. The four modes are: Poly Omni On, Poly Omni Off, Mono Omni On, Mono Omni Off. The primary effect on the synth is whether it responds to more than one note at a time (mono/poly) and whether it responds to a single channel or all channels (Omni off/on)

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MODULAR
used to differentiate the more portable analog synths of the 60's/70's from the large integrated studios such as Columbia-Princeton. So-called because the individual components: oscillators, filters, etc., were usually self-contained within the body of the synth, and sometimes were even pluggable, such as in the ARP2500.

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MONITOR
Verb: To listen to or view the output of a system, in such a way as not to interfere with it. Thus, any mixer worth having should provide several ways of tapping into the sound flowing through it without disturbing any other settings. Some of the mid range Mackie boards, for instance, have dual main outputs, utility outs, fx sends, tape outputs, any of which can be used for monitoring. Noun: A set of speakers or video screen used for monitoring.

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MONO
Monophonic, meaning that there is only a single channel of sound. Mono is used to distunguish a sound from stereo, where there are two channels.

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MONO MODE
the MIDI mode which causes a synth to only be able to play one note at a time.

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MOTU
Mark of the Unicorn, a software company specializing in MIDI, based in Cambridge, MA.

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MTC
MIDI Time Code, a software convention which allows MIDI sequencers to communicate with SMPTE timecode.

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MULTI MODE
The most recent of the MIDI modes, which allows a properly equipped synth to play up to 16 sounds on 16 channels simultaneously.

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MUSIQUE CONCRETE
The art of forming musical material out of electronically recorded 'sound bites', music which rose into being as the result of the invention of the tape recorder.

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MUTE
to prevent output of a particular channel in a mixer, or to prevent input in a recording device.

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NEGATIVE
A surplus of electrons creates a negative charge. It is the flow from negative to positive which accounts for electricity, though of course the convention has it going from positive to negative.

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NEGOTIATE
the process whereby one communications device talks to another inorder to figure out how fast it can send information to or receive information from it. Realaudio allows you to, based on the way you name the files, automatically negotiate the best performance with a variety of modem speeds. Other formats build the negotiation in and adjust the streaming content to match the negotiated speed.

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NODE
A harmonic node is a spot along a vibrating surface where the motion becomes less. This is because there is a simple integer relationship between that spot and the start or end pont of the surface that coincides with the wavelength of the vibration.

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NOISE FLOOR
Simply put, with your audio system idling (no sound coming in from a mic, etc.), the noise floor is any hiss that you can still hear. The goal in good recording is to widen the gap between that noise level and the recording as much as possible. You accomplish this by using balanced equipment wherever possible, matching impedances, setting proper recording levels.

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NON DESTRUCTIVE
an editing method in which pointers to a sound file are used to allow 'virtual' manipulation of regions in the sound. So-named because no changes are made to the underlying sound file, instead the result is 'bounced' to a new file.

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NON LINEAR
the tendency of cheap devices to produce unpredictable output amplitudes for predictable inputs. See linear.

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NORMAL
In analog sound, normal has two important meanings. Your goal is to keep all audio levels "normal" as much as possible, meaning that you don't want to have to crank up the volume of a sound in such a way as to overdrive the device which you're putting the sound through. Normal in this context means that whatever audio devices are participating in the channeling of the audio are operating at their peak efficiency. Most devices have tactile and visual indications of the settings that will give you the Standard Reference Level of each. See GAIN above.
The other meaning has to do with the wiring of a studio through a patchbay. If the studio is "normalled", then the equipment in the studio can be connected in various ways without the need to plug them together via the patchbay. If two devices are "normalled" together, then they are already connected, usually through a mixing board. You can generally bypass normalling through the use of patch cords.

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NORMALIZING
A digital process whereby a soundfile is scanned for the highest amplitude, that amplitude is raised to the highest possible level before distortion, and then the remainder of the soundfile is multiplied by the same value. This safely boosts the output of the signal to the maximum possible setting without introducing distortion, and, unlike compression, doesn't fiddle with the sound's dynamic range.

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NOTCH FILTER
Another term for band reject filter. (see entry above).

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NOTE
a musical event. In midi, a note is generally required to hear the output of a synth, though there are other applications of midi (effects processors, mixers, etc.) where the sonic input may be supplied in some other way. Typically one may say that a note is a clearly partitioned musical event with a distinct start and end (see envelope). It is the midi message 9(0-F).

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NOTE NUMBER
A number from 0-127 which refers to a location on a MIDI controller keyboard. Note number 60, for instance, refers to middle C (though depending on what you've done to your synth, middle C could have any sound under the sun, so you have to take that with a grain of salt). Technically it's the first data byte of a note-on msg.

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NOTE OFF
see MIDI NOTE above. Must have a velocity of 0.

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NOTE ON
see MIDI NOTE above. Must have a velocity above 0.

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NYBBLE
half of a byte (really)

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NYQUIST FREQUENCY
1/2 the sampling rate. For a given sampling rate, the highest frequency which may be allowed to be recorded can only be half the sampling rate. This is called the Nyquist frequency. See ALIASING.

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(OBJECT)~
A Max object with the tilde (~) indicates that it is an MSP object, and can send and receive audio data as well as typical max messages.

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OBJECT BOX
a MAX group of functions, so called because it resembles a box with inlets and outlets. Objects are the primary tool of MAX.

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OCTAVE FILTER
A graphic equalizer tuned in octaves.

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OMNI
Omni-directional: a microphone which picks up sound in a complete sphere around it.

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OMNI MODE
The MIDI mode which allows a synth to receive any incoming signal regardless of its channel. Great for doing a quick mixdown to a single instrument (piano reduction).

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OMS
the Open Music System (formerly Opcode Music System). System level software which is used to govern connections between a midi interface any all midi devices and software attached to it.

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ONADIME
Now that nato has blown the lid off realtime video processing, several groups have started to come out with their own ideas. Max itself will probably start introducing similar technology in later versions, but other competing products are also starting to emerge. One such item is Onadime Composer (www.onadime.com), which offers a set of modular tools for integratinf video with audio/midi, etc.

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ONDES MARTINOT
one of the original keyboard synthesizers, favored by several composers, including Edgar Varese.

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OSCILLATOR
A device which produces periodic signals (waves). They comprise the primary sound producing element in a conventional synthesizer.

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OSCILLOSCOPE
A device for visually measuring sound. Its simple electron beam that scans across a picture tube is capable of being deflected up or down depending on the incoming voltage. Therefore, the oscilloscope can faithfully reproduce such things as audio waveforms.

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OUT
the port on a midi device for transmitting the midi stream.

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OUTLET
graphic outlet on the bottom of a MAX object box, allows data to be sent elsewhere.

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OUTPUT
The part of an audio device which emits an electrical signal. Output can occur at several strengths, from a very weak MIC level, to levels strong enough to drive large physical devices, and of course, speakers. The two kinds of output most commonly encountered in audio are the MIC level (usually measured in microvolts) and LINE level (measured as a ratio between 10ths of a volt and the decibel level of the output).

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OUTPUT STAGE
The section of a mixing board that sums together the many channels from the input stage. The output stage typically has more than a single set of outputs, selected via the assignment buttons in the input stage. The output also contains returns from the aux sends, sometimes has built-in FX, and a number monitoring options.

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OVERDUB
To merge midi material over the top of a previous recording, adding the two together. In the old days this had to be done by "bouncing" the two signals to a third track. With MIDI, new data can be merged right into the stream of old data on the same track. With digital audio, tracks can be merged and mixed with none of the loss of fidelity that was such a problem in the analog days.

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OVERTONE (HARMONIC)
A multiple of a certain frequency, usually by a whole number. For instance, the third harmonic of 'A' is achieved by multiplying that frequency by 3, and results in a tone an octave and a fifth higher in pitch.

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PACK/UNPACK
a MAX object which assembles individual arguments or values into a list, or disassembles a list into individual arguments/values.

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PACKET
a method of arranging data in a serial stream into regular sets of chunks os specific size, usually accomplished by putting a start bit and stop bit at the beginning and end of the chunk of data, respectively. Thus midi messages, even though we only care about the eight bits minimum in a message, actually contain 10 bits.

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PAGE
A method of organizing the user interface on a synthesizer. A page is simply a screenfull of data, categorized by related functions, e.g., midi modes, multi patches, etc.

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PAN(orama)
Channel message B(0-F) 0A (0-7F), the messange which allows a sound to be sent to a certain portion of the right or left channel, effectively moving it in space.

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PARALLEL
the capability of a data port to send/receive numbers more than one bit at a time.

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PARAMETRIC EQUALIZER
a bank of filters which gives you control over a very specific range of frequencies. The difference between a real parametric filter and the other typews on this page is in its sophistication. The device is designed so that you can zoom down to a single frequency and then fine tune the surrounding bandwidth, generally either to bring out a certain range or lift out offending frequencies.

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PARSE
to be able to take a continuous stream of data and "see" the meaningful chunks (see packet) of data within it.

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PASTE
To insert copied or cut material at the cursor. If audio is selected, it will be replaced. Depending on the siftware, the rest of the copied audio either will or will not be pasted after that part. In the former case the file length will change.

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PATCH
The most misused term in all MIDI. A patch SHOULD mean a complete sound in a synth as you call it up from memory. In fact that IS what it means but manufacturers have not deemed it necessary to standardize and agree upon exactly what level the word patch is to appear at. Thus in one synth, patch is the most basic sound component, while in another it is a combination of umpteen other sounds. Synonyms for "patch" are: performance, voice, preset, tone, timbre, sound, wave, and others.

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PATCH CORD
id a cable used to quickly 'patch' a signal from one place in an open ended electronic music architecture, such as either an integrated studio/patchbay, or in a modular synthesizer. Computers now often use a patchcord metaphor for the passing of values between functions.

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PATCH NUMBER
refers to the number in the synth bank where a certain patch is to be found. e.g. "patch 00, 'Universe' ".

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PATCHBAY
A rack of jacks installed in a studio that allows you to connect equipment together. A patchbay normally has two rows, with the top row connected directly (see NORMAL) to the lower row. The top row contains the OUTPUT signal of various devices, while the bottom row is the INPUT. For instance, if you were to read out patchbay in the advanced sound lab, you would see that the top left pair of jacks is labeled "mix out 1,2", and directly underneath is another pair of jacks labeled "Pro Tools L,R", meaning that the master output of the mixing board is already connected to two inputs of our ProTools system. The normal connections can be changed by inserting a PATCHCORD into a jack and inserting the other end into any device you wish to send or receive a signal from.

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PATCHER
MAX term for a program using max objects.

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PATCHLIST
A listing of all the patches in a particular MIDI instrument's bank. MOTU software such as the PatchList Manager was conceived to keep track of such lists, which can often become difficult to keep organized.

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PATCH THRU
in a sequencer, allows the input midi device to automatically be routed to the designated output device, usually when the input track isw record enabled.

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PCM
Pulse Code Modulation, the most widely used method of making an uncompressed digitization. Examples of PCM are he .WAV and .AIF format. Very simple in structure, but much bigger filesize, since there's no compression. At 44.1kHz, 16bit resolution, about 10 megs/minute. Thus there's hard limit to the amount of music you can fit on a standard audio CD, which holds about 800 megs. There's nothing to stop you from going DVD though, is there?

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PEAK AMPLITUDE
The largest magitude available to a sample, depending on the bit depth. In 8 bit it is 256, in 16 bit it's 65536. These are of course scaled down to the resolution of the system.

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PEAK LIMITING
A recent development in software perfected by KS Waves, which allows you to increase the overall amplitude of a digital audio file up to 30db above its normalized maximum without introducing distortion, thanks to a sophisticated "look ahead" algorithm that analyzes and adjusts the waveform as it's increasing it.

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PEAK/NOTCH FILTER
A singel filter which contains the ability to act as either a band pass or band reject (see above) filter. You generally have control over the BAND of frequencies you either want to boost or reduce, and the amount you want to boost or cut them.

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PERFORMANCE MODE
One of the terms for "patch". A performance, as its name implies, usually organizes the synthesizer in such a way as to lend itself to live play as opposed to studio work. In a performance, as opposed to the more conventional definition of 'patch', sounds may be layered, controls may be set to affect several channels at once, etc.

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PERIOD
Since sound by definition is periodic (meaning that the perceived continuity of it is actually due to an underlying pattern (wave) repetition, a 'period' refers to a single complete iteration of whatever it is that is repeating. In other words, a complete wave cycle is an example of it's period.

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PHANTOM POWER
Condensor mics need juice. Some allow you to supply electricity via a battery, others are capable of using voltage supplied directly from the device they're plugged into, this is 'phantom power'. Typical power levels are 12 or 48 volts. Phantom is not available on every device, and is not available in every condensor mic. Only mics equipped with three conductors (balanced) can support hantom, since it uses both the hot and cold pins of the alancd line and references the voltge o the ground pin. Thanks to this, it is fine to plug in a dynamic mic into a phantom-powered jack, it will just ignore the extra vltage.

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PHASE
The specific location within a single cycle of a waveform. Phase measurement usually splits a wave into 360 degrees, thereby allowing the wave to be analyzed using standard trigonometric formulae. A Wave begins its phase at 0 degrees, and ends at 360. The mid point of the wave is 180 degrees, etc.

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PHASE SHIFTING
a technique similar to flanging (see above), achieved through a device which varies resistance as phase cancellation moves up and down the frequency scale.

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PHASOR~
A MAX sawtooth wave generator. Useful for an audio source or as a control.

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PHONE PLUG
Also referred to as the 1/4" or guitar plug, this general purpose plug is used to connect together many types of audio gear, from mixing boards to musical instruments. It consists of a long metal post (known as the "sleeve") at the end of which is a separate conductor (the "tip"). Phone plugs also come in a three-conductor version, in which case the sleeve and the tipe are separated by a third conductor, called the "ring". Thus, the phone plug can be used as either a balanced mono plug, or as an unbalanced stereo plug. In a balanced use, the tip is hot (see XLR below), the ring is cold, and the sleeve is ground. In unbalanced stereo, the tip is used for the right channel, the ring is left, and the sleeve is the common ground for both.

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PIANO ROLL NOTATION
Sometimes referred to as 'graphic editing mode', this is one of the ways of looking at and working with midi data in a sequencer. Sucvh a method is very intuitive, since you can see the actual duration and pitch of notes represented by their length and vertical position on a grid.

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PINK NOISE
'colored' noise simply means white noise which has had various parts removed. In the case of pink noise, the amplitude slopes off 3dB per octave. Since the ear hears higher frequencies as seeming louder, this gives the noise a generally more even pitch distribution.

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PITCH
The sensation produced in the ear when a perceived vibration reaches a frequency greater than around 20 cycles/second. The human sensation of pitch spans a a range from around 20 cycles per second to around 20,000 cycles per second, after which we can no longer hear anything. Sound can, of course, be heard below 20 cycles per second, but the nature changes so that pitch per se is no longer noticible.

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PITCHBEND
one of the standard midi controllers (status byte E0-EF), pitch bend enjoys the distinction of being a 'double-precision' controller, meaning that both the first and second data bytes serve the purpose of tuning the note. Since all 14 bits of usable midi are available, unlike the typical controller that only gives you 128 separate divisions of control, pitchbend allows you to bend the pitch of a note to as fine a resolution as 1/8192 of a half step. Wow!

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PITCH SHIFT
the process of raising or lowering pitch of an audio clip, either with or without affecting its duration.

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PHONE
Another term for the TRS type connecter or 'guitar' plug. So names because the phone operators used that type of plugs in the oldern days. Phone plugs come in both balances and unbalanced, stereo and mono versions.

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PLANE
Jitter term for the 'z' parameter of a matrix. Think of it like a layer in photoshop, one stacked on the other, all simultaneously visible. This makes it possible to easily perform operations on a single channel of video, the red layer, say, or play with sophisticated keying using color layers

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PLAYBACK HEAD
either a stationary (tape recorder) or rotating (VCR, DAT) electromagnet which transduces change in magnetism on tape as it passes across it into electrical signal.

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PLUG
The plug is the hardware which allows you to patch together different pieces of electronic equipment. It consists of a protective housing surrounding one or more conductors. Plugs are made in standard shapes which are often designed to prevent you from accidentally plugging together incompatible gear. Plugs are attached to various types of cable, which is optimized for specific purposes. Various types of plugs and cables are given elsewhere in this glossary.

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POINTER
a variable which stores the address of a location in an audio file, making non-destructive editing possible.

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POKE
to insert a value into a stream of data.

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POLY(phonic)
the midi mode which allows a synth to play more then one note simultaneously.

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POP EDITING
The process, in a midi sequencer, of selecting an individual event to be changed. For instance, in MOTU Performer, you double click on a note, then you can play any key on your keyboard to change the note.

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PORT (CABLE)
A port is a set of 16 midi channels. It represents, in both hardware and software, the physical link between the midi interface and a particular synthesizer. In the simplest midi setup, the port is irrelevant, since there is only one connection available, limiting the channels to sixteen. With a more extensive interface such as the MOTU Midi Timepiece however, you can link as many as eight synths to the computer, giving you a total of 128 channels.

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POSITIVE
In electricity, the word 'positive' implies a deficiency of electrons, which are considered 'negative'. Since there aren't enough electrons, 'holes' are created. In this manner, current is made to flow, so that new electrons rush to fill the 'vacuum' left by the retreating ones.

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POST
Supercollider's 'listener' window, which gives you feedback about the ongiong processes in the app. Synonyms in other apps are: 'console', 'terminal', 'Max Window'

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POT(ENTIOMETER)
Technical term for a rotary knob used in controlling some parameter of sound, such as panning it in a stereo field. Pot, for short. Another such rotary switch is the rheostat, used in light dimmers and volume faders.

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POWER AMP
The device that gives the audio signal it's final 'kick' up to the power level needed to drive speakers. An Integrated amp has both preamp and power amp in one.

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PREAMP
The device that you send your weakest audio signals to in order to get them up to Line Level. A typical voltage lveel from a non preamplified mic is around 40 microvolts. The preamp is arguably the most important part of your audio system, since that's where the signal gets its initial amplification, therefore is the place where it's going to be most sensitive to interference, distortion, etc. Of course somebody will then say that it's the speakers that are the most important part. Ultimately it's probably your ears that are the most important part..

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PRESET
Another term for 'patch'. A preset implies that the sound is easily accessible by finding its location in the memory of the synth.

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PROG MODE
In the Korg M1, program mode is analogous to 'performance' mentioned above. It sets the synth to the global midi channel and allows only one patch at a time to be played.

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PROGRAM
Another term for 'patch'.

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PROGRAM CHANGE
The midi message C(0-9) (0-7F), which sets the sound for a particular channel to some stored patch in the synth's bank.

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PROGRAM MODE
A synth setting which sets up the instrument for single-channel use. This is sometimes useful if you plan to make a very rich patch which will only need to receive on a single channel.

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PUNCH IN
a feature in the recording process which allows you to 'drop in' to record mode at a predetermined point. The advantage is that you hear what you've done and play on top of it, then when the time comes you are automatically recording new material over the old. Recording can similarly be terminated (punch out).

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QUANTIZE
To quantize means to 'straighten up the rough edges'. It refers to a method employed in midi sequencers for correcting rhythmic errors in performance. You first select a quantize 'grid', that is, you pick the smallest rhythmic note value that won't change the obvious rhythms of the music. Then, when you quantize a portion of music, all rhythmic values will be changed so that they fall on those grid marks. More sophisticated software allows you to specify the amount of quantization, so that you don't end up with square 'robotic' sounding music.

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QUANTIZE(2)
In digital audio, quantize can be any effect which reduces resolution (in the sense of 'symmetry breaking'). One can quantize parameters in the grain~ object, for instance, to limit the range of pitches hit by random modulation of the signal. In digital audio, quantize noise is what you get when your bit depth isn't deep enough to accurately reproduce the slight random changes in amplitude at the bottom of the dynamic range.

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QUARKS
Subversion-managed repository for Supercollider plugins & classes.

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QUICKSCRIBE
A Digital Performer feature which displays midi in musical score form. Like PianoRoll notation (graphic), you can edit data by pulling, moving, stretching, etc.

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RAREFACTION
The opposite of compression. The phenomenon whereby the air, after having been compressed by the force emitted by a sound producing object, becomes thinner as the action/reaction principle forces the colliding molecules apart. This also contributes to standing waves. Eventually the air absorbes the energy of the sound and it dies away, like ripples in a pond.

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.RA
the format for encoded Realaudio material.

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.RAM
RealAudioMetafile: small single line text file that you put in your html page, which allows the user/browser to listen to the underlying realaudio material only (no download/copy). Usually points to a .ra file on a realaudio server. Example: pnm://111.11.111/me/my-rapiece/rapiece.ra.
.ram is used when you want the metafile to act as an anchor.

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.RPM
same as .ram, except you use the metafile as an EMBED command instead of a plugin. The contents of the file are the same as .ram.

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.RA SERVER
a dedicated server which one can buy from RealNetworks which allows for highspeed streaming of Realaudio and video.

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RF INTERFERENCE
Radio Frequency Interference. We are always swamped in electromagnetic soup. Any audio device that isn't properly shielded will pick up a certain amount of it, and some of it is in the radio frequency range, which means your audio circuitry will treat it just like any other part of your recording, amplify it, and mix it right in. RF interference sounds like noise with a little color once in a while.

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RCA (PHONO) PLUG
The most widely used audio connector in the consumer industry, the tiny RCA plug (named after the company) is a coaxial connector, consisting of a central pin (+) surrounded by a metal ring (- and ground) Since it only uses two conductors it is unbalanced. The RCA plug is usually connected to coaxial audio cable (see above).

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REAL AUDIO
One of the first efforts to provide 'streaming' audio over the Web. It involves an encoding/decoding process in which the sound file is shredded into practically nothing, with predictable results. The 28.8 version is beginning to approach a.m. radio in quality, but no one is quite there yet. The general assumption is that we'll have to wait for higher bandwidth on the Web before CD quality audio, or anything approaching it, becomes feasible.

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REALTIME
any process, recording, processing, etc., that can occur in the computer fast enough to be perceived as happening 'on the fly'.

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REDBOOK AUDIO
The set of specifications for a standard audio CD. The 'books' refer to whether the cd is to be used for audio, cd-rom, cd-interactive, etc. Really just a list of specifications, such as the size of the cd, capacity, etc.

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REFERENCE TONE
A steady signal, usually a sine wave at either 440Hz or 1000Hz, used to set the level between a recorded tape and a dubbing or transmitting device. The idea is to get the same level (the "0" reference level) between the recorded sound and the device which it's going into.

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REGENERATION (FEEDBACK)
A phenomenon in which sound is allowed to travel from an output back into an input, by virtue of the two being connected together. This causes a particular resonant frequency to quickly intensify in volume and drown out all other parts of the sound, eventually resulting in an ear-splitting sine wave. Feedback can also be controlled and shaped, routed through different devices, equalized, etc., to yield some rather beautiful musical effects, as any Hendrix fan knows.

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REGION
A highlighted area of a digital audio file or midi file. In a digital audio file, a region defines a 'non destructive partitioning of a contiguous file, allowing you to treat the same file as many different ones.

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  REICH, STEVE
Minimalist composer, noted for many innovations in composition, including the use of repetitive, gradually varying loops. Listen to "It's Gonna Rain" and "Different Trains".

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  RELAY
primitive electronic device which routes a signal to one place or another based on the incoming voltage. Used in electronic music instruments before the "valve" (vacuum tube) was invented.

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RELEASE
The last part of an ENVELOPE. It is the release of the guitarist's finger on the fretboard, the lifting of the piano key, the stopping of airflow in the tuba. Some sounds jump right from the attack to the release, such as a plucked guitar string, but most instruments allow for the musician to 'preemptively' stop the sound.

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REPLACE
Similar to paste, only you don't run the risk of changing the file length. It only replaces material from a selected area. Good for fixing problems in a contiguous soundtrack for video, for instance.

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RETROGRADE
To reverse the order of a particular parameter of a stream of events. For instance, the rhythm of a tune can stay the same, while the pitches can go backwards, or vice versa.

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REVERBERATION
Reverberation is what happens to a sound when it bounces around in a particular space. Technically it's a form of echo, but unlikt simple echo, the sound undergoes many transformations and multiplications as it is reflected and refracted across many different surfaces. Reverb is affected by the size of the room, the angles of the walls, the materials covering the surfaces in the room, and a host of other such variables. In digital sound, a digital reverb unit is employed which contains a set of algorithms for duplicating such effects on any sound which is passed through it.

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RING
The center conductor in a TRS type plug. Usually carries either the cold, or negative current in a balanced plug, or the left channel in a stereo unbalanced plug.

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RIPPLE EDITING
An editing method in which all mterial after an edit point on a timeline is shifted later or earlier when material is added or removed. Also known as shuffle or insert diting. Opposite of 'overwriting' or 'slip' mode.)

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.RMFX
an extension to .rmf which allows you to put your own samples into the file.

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ROUNDING
One of the methods used by audio software in dealing with the leftover 8 low order bits in the downsampling process. In going from 16 bit to 8 bit, rounding produces a smoother sounding file that the previously used 'truncation' method, which simply threw out the low order bits (causing some pretty serious jumping between amplitude values in the quieter moments of the sound, giving it that characteristic 'sizzle' that gave 8 bit sound such a bad name. Now, by combining rounding with peak limiting, you can get a very smooth sounding 8 bit file.

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RUBBERBAND
a method of editing volume or pan info in a soundfile using a stretchable onscreen line between user defined breakpoints (see). One can thus draw changes which are applied nondestructively to the particular parameter of the sound track.

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S/N RATIO
Signal to Noise ratio. A measurement of the total available dynamic range of an audio device. A 45db s/n means that there is only 45 decibels between "silence" in a recording and the maximum volume. A cassette deck with no noise reduction would produce something like that. Digital systems such as DAT recorders have upwards of a 95db s/n ratio, rendering the "noise floor" (see above) practically zero. Tape hiss is a sign of a lousy s/n ratio.

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S/PDIF
"Sony/Phillips Digital Interface Format", the standard for connection between digital devices most commonly used in consumer grade audio devices, though it's just as likely to be found in pro digital studios as well. You can recognize the interface by its' RCA connectors, one for input and one for output.

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SAMPLE
1. noun: a (usually short) digital recording. 2. noun: an instantaneous value captured by a digital recorder, consisting of a pair of numbers (time from the start of recoding and the amplitude alue at that instant). 3. verb: to make a digital recording, including taking digital 'snapshot' of an instantaneous amplitude.

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SAMPLER
a synthesizer which, instead of generating its own sounds through internal algorithms, allows the user to build instruments out of small digital recordings. The recordings are then 'mapped' onto a keyboard to give pitch references. Loops, modulation, etc. are all under control of the software, so with a fairly small amount of sampled material, one can generate a wide variety of instruments simply by applying different effects to each.

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SAMPLING RATE
In digital audio, the sampling rate is the speed at which an analog signal is quantized into separate numbers for storage in the digital system. Audio can be digitized at a large number of frequencies, depending on the desired fidelity of the sound. The higher the sampling rate, the better the sound, but the more disk space it will occupy, and the slower it will run on the comupter (that is, the more memory intensive it will be).

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SCRUB
to produce sound in either a software editing system or recording device by slowly moving the playback head (or tape in the latter case), for cueing purposes. In jog scrubbing you have complete control over the movement of the head, while in shuttle the machine tries to 'play' the material at a speed based on your initial motion of the head/tape.

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SD II
Sound Designer II, digital audio software by Digidesign.Also refers to the sd2 file format, widely used in the pro audio and video industry, such as Avid, Media100 etc.

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SELECT
Generally, you can't do anything to a midi file unless you've 'selected' something, that is, you've either clicked on a note or dragged the mouse to select a region of notes or data to be edited. In digital audio, not selecting a particular region for editing usually implies to the software that you want to change the whole sound file. Be Careful!

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SEND/RECEIVE
MAX objects which allow you to pass variables around inside a patcher (and outside) without using visual patchcords.

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SEQUENCER
Software or hardware that arranges notes and midi controllers chronologically. In other words, music makers. The analogy of a sequencer is a tape recorder. The difference is that a sequencer records controller information, not actual audio, which is a separate process.

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SERIAL
Opposite of parallel. Serial means 'one thing after another', and so refers to data communication in which a signal is transmitted/received as a single changing digit.

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SESSION
also known as Project and/or EDL (edit decision list), a file in a non-destructive editing environment which stores information and pointers to a collection of audio and video clips.

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SHIELD
The part of an audio cable, usually a braided wire wrapping up and down the entire length of the cable, that serves to block stray electromagnetic interference. Sometimes helped out with a 'drain' wire.

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SHUFFLE
Similar to Ripple Edit mode: in Pro Tools, shuffle mode allows you to trim and move clips in such a way that any space between them is 'taken up' or removed automatically.

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SINE WAVE
The simplest of all VIBRATIONs. All sound waves, no matter how complex, can be found to be composed of a collection of sine waves. The sound of a pure sine does not exist in nature, but is roughly approximated by the sound of a flute. It gets its name from the mathematical formula from which it's derived.
SIN
the sine function. Imagine a dot moving counterclockwise around the perimeter of a circle (usually represented with a radius of 1). The sine is the position at the intersection of the horizontal and vertical lines that would stretch from the dot to the center of the circle with respect to the vertical, that is to say, the ratio between the length of the two lines thus made.
http://mathworld.wolfram.com/Sine.html
All sound can be shown to be made up of combinations of sines and cosines at different frequencies, phases and amplitudes. This is the Word of Fourier..

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SLEEVE
The longest metal part of a 'phone plug' type connector. The sleeve is the negative part of the current in an unbalanced line, or the drain/ground in a balanced line.

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SLIDER
graphic controller used in MAX.

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SLIP MODE
In Pro Tools, slip mode allows you to freely move clips around on the timeline. Contrast with SHUFFLE.

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SMOOTH
When you splice two different types of audio, smoothing averages out the samples across the splice much like a crossfade. It can also be used in the same way to diminish artifacts within a region of audio

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SMPTE
Society of Motion Picture and Television Engineers. An organization which created the standard for synchronizing pictures and sound. Standard SMPTE code operates on a 24 hour clock, which is split up like this: 00:00:00:00 to 23:59:59:29 (hours, minutes, seconds, 'frames'. The last number can vary, depending on the speed of the program material. Film splits the second into 24 frames, video into 30, broadcast video into 29.97.

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SNAP
a mode in most editing programs which enables you to easily move clips around the timeline in such a way that they automatically align themselves with a time grid.

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SND
(archaic)The standard format for sound files on a Macintosh. Snds are usually organized into resource files, where one file will contain several snds, for portability and ease in updating.

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SNIP
In a midi sequencer, to remove a chunk of time ina track, pulling everything that came after toward the beginning accordingly.

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SOLO
inverse function of mute. When you press the solo button for a channel, all other channels are muted, except for any others which also have solo pressed. When you mute, only that channel is stopped, along with any other muted channels.

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SOUNDBITE
A digital sound, usually a small portion of a larger file which has been separated non-destructively (via pointers). Also known as a REGION.

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SPLICE
to join together two different regions of audio.

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SPOT
A Pro Tools mode which automatically puts the beginning or cue point of a clip at a designated SMPTE location on the timeline.

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SQUARE WAVE
A waveform which is widely used in the audio industry. It is rich in harmonics, and is special in that it contains only 'odd' harmonics (1st, 3rd, 5th, etc.), in a linearly decreasing amplitude scale. For instance, the third harmonic is 1/3 as loud as the fundamental. The shape of the square wave, having a very quick change from maximum amplitude to minimum, also makes it useful for timing in computers and clock driven devices. A more versatile variation of the square wave is the PULSE wave, in which the 'top' and 'bottom' widths of the wave can be adjusted.

Bear in mind that, even though the ideal form of the wave appears to instantaneously rise from its minimum to maximum level, such a thing isn't physically possible. Actually a whole lot of interesting things occur at the 'corner' where the change of amplitude happens. Look closely at that spot and you can get a very good idea as to why the square is so rich in harmonics.

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STANDARD MIDI
Most midi programs create their own proprietary formats for the midi stuff they do. Fortunately they also allow you to save a file in a more universal format called Standard Midi. A file in this format can either have track information (format1), all data on a single track (format0), or simply be a tempo map (a list of tempo changes, key changes, meter changes, and where they happen). This file is easily transportable, since it's really just a text file. It's up to the midi player software to make sense of it.

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STATUS BYTE
The first part of a midi message, which tells the synth or computer what sort of event is about to happen (e.g., 'note on).

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STEP RECORD
A feature in a midi sequencer which allows you to record data note-by-note. A notepad style interface allows you to specify each rhythmic value before you play it, duration of the note, velocity, etc.

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STEREO
The psychoacoustic illusion of spatial placement of sound, accomplished through the use of a pair of speakers.

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STREAM
To broadcast audio or video (or any kind of synchronous data) on the web. Usually accomplished by buffering some of the material in ram as it comes in, so that when the inevitable bogs in transmission occur there will be enough resident in the local computer to be able to keep playing. Rarely works well, still, at least in most areas still using std. telephone lines for their modems. On the other hand, in highspeed scenarios, intranets, etc., it works amazingly well. We are pretty much at the point that yhou can really start thinking about what content you'd like to broadcast, instead of how much you'll have to sacrifice to get it to stream at all..

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STUB
A special 'empty' file which is used in Beatnik when you only want to access the sound banks on a note by note basis (instead of playing an entire file). The stub.rmf file is part of the standard installer package.

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SUBMIX
Most good mixers allow you to route a signal to more then a single set of outputs, for any number of purposes. Sometimes you want to group a set of inputs together so they can be easily controlled together, in the context of a larger mix. This would be a submix. You assign all the outputs of those channels to a 'group' output, usually numbered, then route that output as if it were simply another input channel to the main output.

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SUB PATCHER
MAX's capability of having a patcher embedded in another. There are two varieties: a completely embedded patcher (the 'p' object), or an external patcher (any MAX patcher name in the search path which is types into an empty object box.) Be sure not to use whitespace in the names of sub patchers.

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SUBOTNICK, MORTON
Composer, widely known for his electronic pieces. Only composer to have been commissioned by a major record label to do an entire series of electronic works (Silver Apples of the Moon, Until Spring, The Wild Bull, Touch). Inventor of the Ghost Box, a programmable device for doing realtime effects processing during a performance.

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SUBVERSION
Open source tool for downloading, uploading and maintaining open source software. Arguably the best method for getting the latest Supercollider builds.

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SUSTAIN(1)
The third part of the standard envelope of a sound. The sustain level is the volume to which a sound arrives after it finishes its initial DECAY. Some sounds have no sustain and simply die away, others, like the winds and brass instruments, continue at that level until the player stops the flow of air through them. In an electronic keyboard, sustain level continues until a key is released.

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SUSTAIN(2)
MIDI control change 64 (40 hex), emulates the effect of a piano damper pedal.

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SWF
ShockWaveFlash file, a Flash file which has been web-optimized.

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SYNC
Sync refers to the way the digital clock that governs the sampling process refers to any connected devices. It can be internal (each device using its own) or digital (one device reading off the clock of another).

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SYSTEM EXCLUSIVE
Midi message F0. A useful loophole in the midi spec, which allows one access to the inner parameters of a particular synth which is not possible using conventional midi messages, such as tweaking the envelope on the fly of a particular sound component in a complex patch.

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SYNTHESIZER
To synthesize means to generate a new sum out of disparate parts, to blend them together so that something new emerges. A synth is an electronic instrument which employs either hardware devices or software/firmware algorithms to provide basic building blocks for the generation and manipulation of sound.

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SYMBOL
MAX's version of a string type. Used as argument to an object.

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SYSTEM MESSAGE
status bytes F0-FF. These messages affect an entire synthesizer, sequencer, etc., as opposed to a specific channel on the device. Patch dumps and individual parameter changes are aspects of system messages, as well as midi time code.

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TAKE
A (successful) recorded segment.

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TEMPO
The regular measurement of the flow of rhythm in music or progression of events in time.

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THEREMIN
A preset point at which something happens. For instance, in a noise gate, the threshold is the point the sound must fall down to in volume before it gets cut off.

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THRESHOLD
A preset point at which something happens. For instance, in a noise gate, the threshold is the point the sound must fall down to in volume before it gets cut off.

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THRESHOLD OF HEARING
The amplitude point below which you can't hear anything.

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THRESHOLD OF PAIN
The amplitude point above which you blow your ears out. See Led Zepplin.

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THRU
a midi port which duplicates the input. Allows one to daisy chain devices, though this practice is no longer used.

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TICK
The smallest unit of time in a sequencer. MOTU performer divides a quarter note into 480 ticks.

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TIMBRE
The "quality" of a sound, also referred to as the 'tone color'. Timbre is a result of the overtone series (a.k.a. the harmonic spectrum) of a given sound. The spectrum changes as the sound continues, and is largely responsible for the "life" contained in the tone of a musical instrument.

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TIMESCALE
To speed up or slow down the speed of events in a midi file by some ratio. This has absolutely no effect on pitch of the music, since you're just slowing down the rate of note-on/note-off commands.

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TIME COMPRESSION/EXPANSION
To alter the duration of a sound file without affecting the pitch. This was practically impossible before digital.

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TIP
The conductor at the tip of a phone plug. Carries the + charge, or the right channel in a stereo plug.

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TOUCH
an automation mode in which a slider will slowly return to its previous point when you let go.

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TONE
Another term for 'patch'. Tone generally implies an 'elemental' or 'primitive' sound that is to be combined and modified to produce a conventional 'patch'. Of course, in Roland synths, a tone can be rather extensive in itself.

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TONE GENERATOR
a synthesizer. A sampler. Used to distinguish the part of a midi device that produces sound from the keyboard or other controlling portion.

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TRACK
a linear partition of midi data. Tracks are mostly invisible to midi itself, and are rather a system employed by a midi sequencer to make it easier to organize music. One can have one track go to several midi channels, or several tracks all go to one channel, etc. The track is an evolution of the track on an analog tape deck. Digital audio also employs tracks in a similar way, sometimes referred to as 'playlists' (Deck II).

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TRANSISTOR
Replacement for the vacuum tube: layers of silicon, doped with other materials to affect their ability to conduct current. Used in all forms of logic circuitry, amplification, etc.

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TRANSPORT
hardware: the physical machine which moves the tape/disk or whatever.
Software: the controls which behave like the above, e.g. forward, rewind, gtz, gte, etc.

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TRANSPOSE
to move a selection of pitches to a different range. In more advanced sequencers, can also be used to alter harmonies.

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TRIANGLE
One of the classic waveshapes used in electronic music. The sound has the fullness of the sinewave, but with a slight buzz or edge. It is generated by creating odd harmonics, where the amplitude of each harmonic is the inverse square of its ordinal number, and every other harmonic is set 180 degrees out of phase.

It also has a lot of usefulness as a simple lookup table structure, since it is a linear increase to the halfway point of the table, then immediately decreases by the same amount to the end.

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TRIGGER
as a verb, trigger means to provide a 'start' signal. It is usually contrasted with 'gate', which means to provide a continuous 'on' signal. A trigger hapens once, then has to be reset for the next time, whereas a gate stays on until you 'let go' of it.

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  TRIM(1)
A control on a mixer which controls the amplitued of an incoming sound channel at its entry point to the board.

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TRIM(2)
a tool in ProTools and video software which allows you to non destructively and visually adjust the beginning or end of a soundfile.    

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  TRS
"tip, ring, sleeve", the three conductors in a phone plug.

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TRUNCATING
The old fashioned way of throwing out the low order 8 bits in a digital sound file conversion, generally yielding Gawd-awful results.

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TS
Tip-Sleeve, synonym for an unbalanced phone-style plug (or mini, or micro plug). Tip is hot, sleeve is cold+ground.

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U-LAW
The Sun Microsystems format for sound.

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UNBALANCED
A circuit which utilizes only two conductors: 'hot' and 'ground'. In an unbalanced circuit, the system or common ground serves as the return path for the audio signal, unlike a balanced circuit, where the ground is separated from the actual signal. Since the impedance of the ground is different from that of the hot signal, more noise is allowed in than in a balanced circuit.

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UNIDIRECTIONAL
A microphone which filters out all but the sound directly in front.

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UNITY
A 'balance' between input levels and output levels. Ideally the voltage being emitted by an audio source should be perfectly matched by the receiving devices ability to accept incoming voltage/curent. Where that's the case you have unity gain. Mixers typically have visual indicators to show you where unity is in the gain controls for a line level input. Of course when there is a preamp involved the unity setting is dependent on the initial trim setting as well.

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USER BANK
Beatnik uses three banks: #0, the general midi bank; #1, their own alternate gm bank, and #3, the user bank, where you can store your own samples. If you have an rmfx file on your page with custom sounds, that's where they go on the client side when the page is hit.

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  VACUUM TUBE
A device which can precisely transfer varying amounts of current via a cathode and anode, separated by a vacuum. Used in early electronic music devices, still used in high end amplifiers and mics because of its warmth in sound.

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VARESE, EDGAR
Composer, well-known for his excursions into the burgeoning field of electronic music in the first half of the 20th C. Listen to Poeme Electronique, Deserts, Ameriques.

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VIBRATION
A periodic change of state. The keyword is 'periodic'. To be a vibration there must be repetition in the change. A tack stuck in the tire of a bus tire creates a vibration when the bus moves. Cards stuck in the spokes of a wheel will create not only a vibration but a distinct pitch if the wheel gets going fast enough. Vibrations often have distinct shapes, referred to as 'waves'.

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VOICE
a single application of sound in a synth, or an individual stream of digital audio. Every system has voice limitations, depending on how many digital oscillators it has, or how fast the CPU is. A typical modern synth has 32 voice polyphony, meaning you can play up to 32 notes before they start swapping off with each new one.

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VOLTAGE
The energy that occurs as a measurement of potential between two or more differently charged areas, electrical 'pressure'.

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VOLTAGE CONTROLLED AMPLIFIER
Part of a synthesizer which can adjust the volume of sound (or other component) via a supplied, changing voltage. Used in conjunction with an envelope generator to provide an overall shape for a sound event.

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VOLTAGE CONTROLLED FILTER
A filter in a synth which can, like the vca above, be controlled by another device such as an e.g.

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VOLUME
The amplitude of a sound, typically measured in decibels (dB).

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VU METER
The visual indicator on a tape deck, mixing board, etc., which gives you a moment to moment reading of the amplitude level of the incoming sound. The VU meter is usually scaled logarithmically, with the standard reference level set to "0".

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WAVE
The shape of a periodic change of state. The shape of the wave determines a number of important aspects of a vibration, such as the TIMBRE of a sound.

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WAVETABLE
a cycle of a periodic wave stored digitally. The table is then scanned at various rates to reproduces pitched sound, or can be scanned slowly to act as a control element.

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WHITE NOISE
The sound created by an equal distribution of all frequencies. Most sound contains some quantity of white noise, and it is usually something to be minimized. The hiss on a poor quality cassette tape is white noise, as the hiss of steam in a radiator. There are variations of white noise, which are produced by limiting the range of frequencies. For instance, "pink" noise is weighted towards the lower frequencies. White noise, since it contains theoretically all frequencies, is very useful in calibration tools which work on a range of frequencies.

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WIRE RECORDER
(archaic) Original name for the tape recorder (used a spool of wire, not tape).

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WORD
a combination of bytes. Digital audio typically employs 1, 2 and three byte words (that is, eight bit, sixteen bit or 24 bit).

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WORD LENGTH
another term for bit depth. Measured in number of bytes per word (e.g., two byte word).

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X AXIS
In a two dimensional representation of sound, the X-axis represents TIME. When talking about individual waves, the X-axis can show the phase of the wave measured in milliseconds. When talking about complete sounds, the X-axis is used to show the total duration of a sound, measured in seconds or even in minutes.

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XLR (CANNON)
A sturdy, three-pin plug which is the standard connector for professional audio. The three pins of the XLR are known as hot (+), cold(-), and shield (ground). They are also numbered for convenience: 1(G), 2(+) and 3(-). The XLR is usually employed in balanced circuits.

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Y AXIS
In a two dimensional representation of sound, the Y-axis represents AMPLITUDE. The scale can take on a number of different forms. In digital sound, the amplitude range usually ranges from -1 to 1 and is scaled by the digital to analog convertor. In analog electronic sound, the amplitude scale often ranges from -5 to +5 volts. It is not where a phase point is at a given moment on that scale that determines the amplitude, rather, it is the average of several jumps from above to below the "0" line that creates a 'loud' signal. Paradoxically, unlike a steady, sustained wind which blows continually in one direction, sound gains its power from periodic fluctuation betwqeen positive and negative. The greater the excursion from high to low, the more powerful the sound.

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ZERO CROSSING
The amplitude midpoint in an audio file. Since files are usually displayed on a positive/negative y axis, this becomes the zero point.