The Glossary

The majority of the text here is taken from the Glossary from the Beginner's Synthesizer FAQ site.

I've tried to contact the author of this page, Chad Gould, but the address given is wrong and the Date of the Page is 1997. Chad if you come across this site - drop me a line!

If anyone has any extra items to add, or any additions to the definitions given here, let know.

The Sweetwater Word for the Day Archive is a very comprehensive A-Z of musical and recording terms. Very useful.

There is also a very comprehensive Glossary on the Sound On Sound website.

32'/16'/8'/4': A carryover from the organ days, simply referring to the octave at which the patch is set at. 8' is the normal sound; 16' is one octave down, 32' is two octaves down, etc. Likewise, 4' is one octave up.

+24db/+12db/+18db:This simply refers to a specific filter type, characterized by how abrupt its cutoff slope will be. This also refers to the amount of poles that are in a filter.

ADC: Analog to Digital Converters. Used in samplers to create digital data (ie, where a sound wave is represented solely by numbers) out of a sound input. The better the bit resolution of the ADC, in general, the better sounding the conversion will be.

ADPCM: An audio compression routine for digital audio.

ADSR: The basic envelope of a synthesizer. This type of envelope is probably the most common type, especially on early synthesizers. Incidentally, each letter stands for a basic parameter of the envelope: Attack Decay Sustain Release.

Algorithm: In computer terms, a set of instructions designed to accomplish a specific task. This computer term has been applied to synthesizers, though, by such synthesizers as the Yamaha DX series. The Yamaha DX series uses the term algorithm to describe how the FM operators are set up and processed.

Amplifier: A circuit which controls the volume that a particular signal has.

Amplitude Modulation: A process that allows you to modify the amplitude (or level) of a sound using various other signal sources. This allows you to produce a range of tremolo or timbre modulation (wah-wah) type of effects. Also known as AM.

Attack: In an ADSR envelope, the control that determines the time it takes to get to the maximum attack level.

Bandpass Filter: A filter that lets through only a narrow band of frequencies.

Bank: Generally refers to a collection of patches grouped together.

Baud Rate: The number of bits of computer information transmitted per second.

Bit Resolution: When people refer to a "16 bit machine", this is what they are referring to. This refers to the amount of bits it takes to store a sample inside of a sampler. A bit, by the way, is the smallest unit of a computer; it is a digital piece of information that is either 1 (on) or 0 (off).

BPM: Beats per minute, the usual tempo measurement.

Buffer: Temporary storage for a patch. You can play it, edit it, etc. without harming the RAM or ROM where the patch came from. Most synthesizers with memory send the patch to the buffer when you call it up.

Carrier: In FM synthesis, an operator that "carries" the main audio output of the sound without modifying (modulating) anything.

Cent: Used to describe pitch tuning. A notation where one hundred cents equals a half step.

Clock Rate: Usually refers to the sample rate at which keyboards play the pre-recorded ROM samples back at.

Combination: A special synthesizer patch that uses multiple patches, spanned across various portions of the keyboard and routed through the same FX, to create a very rich sound.

Controller: A device that is capable of producing some change in the aspect of sound. See the whole glossary of controller terms below (VII. Part D)

Cutoff Frequency: The frequency in which a filter is set to. Beyond this frequency (in a lo-pass filter, the most common), the sound is cut off.

DC Offset:  DC offset is an imbalance that sometimes occurs in A/D converters .   It is a constant voltage that is present which can eat up headroom and cause clicks and pops during editing.

DAC: Digital to Analog Converter. Used for samplers and sample based synthesizers. In general, the better the bit resolution of the DAC, the better sounding the samples.

DCO: Digitally Controlled Oscillator. Similar to VCO, except that the tuning of the VCO is somehow computer-stabilized (e.g. clocked to a single CPU, etc.)

Decay: In an ADSR envelope, the control that determines the time it takes to go from the maximum attack level to the sustain level (set by the sustain control).

Delay: Sometimes refers to delay time before a specific keyboard section starts (such as a delay time in an envelope or LFO); also, a specific FX type, see section VII Part E.

Delay Time: Usually refers to the delay before a specified section begins working.

Detune: These parameters usually allow you to have some of the oscillators be slightly out of tune with the other, creating a fatter sound.

Default patches: The patches that are loaded into the synthesizer when you first buy it.

EG: In some synthesizers, they use the term "Envelope Generator" instead of Envelope; this is a shortened abbreviation for this.

Emphasis: Sometimes used to describe resonance.

Envelope: The signal processing device in a synthesizer that controls amplitude over a time. In not-so-technical terms, it gives sound its shape. It tells when the synthesizer volume should go up and down in volume, and the time it should take to go up and down. Early synthesizers commonly used an envelope type called ADSR, but modern synthesizers tend to have a lot more complicated parameters. The basic concept, however, remains the same.

Envelope Tracking: A function that changes envelope length, time, etc. depending on what note is played.

Filter: A device that blocks certain frequencies while letting other frequencies through.

Frequency: The pitch of a tone. In oscillators (VCOs, etc.), they usually refer to the initial starting pitch. In filters (VCFs, etc.), they usually refer to the setting of where the cutoff frequency begins. In samplers, it sometimes is used to specify the sample rate. Frequency is measured in Hertz, where one Hertz (Hz) is one cycle per second.

Frequency Modulation: In addition to being a basic synthesizer technique used by some synthesizers, many synthesizers have a feature which allows you to modulate the frequency (pitch) of an oscillator or filter, producing rich and complex tones. Also known as FM.

Keyboard Tracking: A function on some keyboards that determines how the area of the keyboard affects tonal qualities.

Hertz (Hz): A way of measuring frequency, where one hertz is one cycle a second.

Hipass Filter: A filter which only lets frequencies HIGHER than a certain cutoff point through.

Inverter: In some synthesizers, a circuit that reverses the normal voltages in the circuit, so that +5V becomes -5V, etc., for special effects.

KHz: 1 Khz = 1000 Hz.

LFO: Stands for "Low Frequency Oscillator". An oscillator that in general is NOT triggered from voltage; it runs continuously at a very low speed (although many synthesizers have a retrigger option that allows the LFO to be reset for each note played, or when you want it). Some common applications: Putting an LFO on the VCO pitch (for vibrato) or putting an LFO on the VCF filter cutoff frequency (for slow filter sweeps).

Loop: An option in a sample that allows you to repeat a sample at a certain point when it reaches a certain point in the sample. In other words, a way to repeat a sample forever. The basic sample loop simply loops the sample from a previous point in the sample when the sample reaches a designated end point; this is called a forward loop or a sustain loop. Other types of loops include the reverse loop (a loop where the sample loops from a point near the end of the sample to a point near the beginning; in other words, reverse of the forward loop) and the bi-directional or ping-pong loop (a loop that plays from the starting point to the ending point, reverses and plays from the ending point to the starting point, and continues ping-ponging back and forth). Some samplers allow two loops: a loop for sustaining a note, and a second loop when a note-off message is received (called the release loop). Also: In a sequencer, an option that allows you to repeat a sequence infinitely.

Lowpass Filter: A filter which only lets frequencies LOWER than a certain cutoff point through.

Matrix Modulation: A type of system which allows you to connect several selectable sources by several selectable destinations by a certain amount. Common on many synthesizers today.

Mix: Often used to describe the amount of volume between one source and another. Often used to describe mixing two oscillator volumes. Also used to describe mixing two samples.

Mixer: A device that combines two or more audio signals.

Modulator: In FM synthesis and elsewhere, a modulator that is used to modify the output of another operator, creating rich complex tones. This process is known as modulation.

Multisample :A "patch" that is made up of several samples spanned over the keyboard. For example, a piano patch could be made up of seven samples, each at an octave point of the piano, spanned over the keyboard. This creates a more realistic sound.

Noise: As it says; random frequencies spitting out to produce static-like sounds. Useful in some patches.

Notch Filter: A filter that only lets everything BUT a certain notched portion of frequencies through.

Operator: In FM synthesis, a digital sine wave that is combined with its own envelope generator. Kind of the FM way of describing a VCO.

Oscillator: A generic term describing the part of the synthesizer that produces the basic tone or sample of the patch. In the old days, an oscillator referred to a specific electronic circuit that oscillated back and forth in voltage, but nowadays, some sample-based synthesizers use this term.

Pan: The placement of the sound between the left and right stereo channels of a synthesizer.

Partial: In a Roland synthesizer, refers to one of the building blocks. Think of it as an oscillator with an independent filter, amplifier, etc.

Patch: A synthesizer sound composed of specific settings. In the old days, you used to patch together modules with patch chords, hence the term formed. Later, "patches" were dialed up on knobs. With the advent of memory, however, patches usually refer to a stored patch inside the synthesizer memory.

PCM: Pulse Code Modulation. A really technical way of describing a sample, often specifically referring to samples hard-coded into ROM. Sample-based synthesizers are sometimes called "PCM synthesizers".

Pink Noise: Noise that has passed through a low-pass filter.

Pole: As in "2 pole filter" and "4 pole filter". The more poles a filter has, the more abrupt its cutoff slope will be, and the more accurate the filter will be in reducing unwanted frequencies.

Port :Refers to an electrical connector of some kind; also refers to a program written for one machine that is translated into another.

PPQ: Pulses Per Quarter-Note. A way of measuring the resolution of a sequencer; the higher, the more accurate notes can be recorded.

Preset: A patch that is built into a synthesizer patches that cannot be changed.

Program: Another word for a patch. In modern sample-based synthesizers, often refers to the patches which use only a single voice in a synthesizer, and are the basic blocks for multimode and combination mode patches.

Pulse: This refers to square waves whose width is somehow being controlled. IE, a normal square wave looks like:

      |-----|     |
      |     |     |
      |     |     |
------      ------|

Pulse waves can look like this:

       |-|       |
       | |       |
       | |       |
-------- ---------
PWM: Pulse Width Modulation. A parameter that controls the width of the square waves. See pulse.

Q: A common name for resonance.

Ramp: On some synthesizers, a smooth modulation that best resembles the attack portion of an envelope.

Rate: The speed at which a particular device is operating at.

Rate Scaling: See scaling.

Reconstruction Filter: From Keyboard Magazine's web site: A lowpass filter on the output of a digital-to-analog converter that smoothes the staircase-like changes in voltage produced by the converter in order to eliminate clock noise from the output.

Release: In an ADSR envelope, the control that determines how long it takes to go from the sustain level to 0 when the note is released.

Resonance: With apologies to Keyboard Magazine's web site, because they said it best: A function on a filter in which a narrow band of frequencies (the resonant peak) becomes relatively more prominent. If the resonant peak is high enough, the filter will begin to oscillate, producing an audio output even in the absence of input. Filter resonance is also known as emphasis and Q. It is also referred to in some older instruments as regeneration or feedback, because feedback was used in the circuit to produce a resonant peak. It produces a very distinctive sound in the analog filter process, and is an important part of techno music, among other things.

Resynthesis: Analyzing the sample and adding frequencies to make the sample sound more real. Used on some synthesizers as a technique.

Ring Modulator: A type of mixer that takes two signals and produces either the sum or difference of the two signals. Cliched in the 70s but not heard of much in the modern era.

Sample: A piece of analog audio encoded digitally. Samples are what make possible much of today's music, as they enable people to take "snipplets" of sound and produce either realistic-sounding instruments or astonishing effects. Technically, a sample is simply one "reading" of audio data, but most people refer to samples as a full snipplet.

Sample-and-Hold (S&H): From Keyboard Magazine, once again: A circuit on an analog synthesizer that, when triggered (usually by a clock pulse), looks at (samples) the voltage at its input and then passes this voltage on to its output unchanged, regardless of what the input voltage does in the meantime (the hold period), until the next trigger is received. In one familiar application, the input was a noise source and the output was connected to oscillator pitch, which caused the pitch to change in a random staircase pattern. The sample-and-hold effect is often emulated by digital synthesizers through an LFO waveshape called "random."

Sample Rate: The rate at which a sample is recorded. It determines how many "samples" are reserved to store a particular sample in the machine. For example, a sound sampled at a sampling rate of 44,100 will require 44,100 samples per second to store the sound. The higher the sample rate, the higher quality the sample will be, with less of a phenomenon known as aliasing (a situation where unwanted frequencies appear in the sample, due to the lack of information present in the sampled data). Each sample will require a certain number of bits to store, depending on the machine. From this, you can calculate the storage space a sample requires (ie, a 16 bit machine requires 16 bits per sample. Monophonic samples require one channel; stereo samples require two. Since 8 bits equals one byte, you can determine that a one second sample will require 88,200 bytes at a rate of 44,100 / 16 bit, monophonic; and double that for stereo samples).

Scaling: Often used to shorten or widen signal processor output (such as the rate of the envelope or the volume level) over a period of time in a particular fashion.

Software Version: Just the version number of the particular synthesizer's operating system.

Split Points: Sometimes used as a term to describe a multisample; a split point is where one sample becomes another.

Suboscillator: An oscillator that is set at (usually) one octave below the normal oscillator; used for bass effects.

Sustain: In an ADSR envelope, the control that determines the level that the sound is played at while the note is being held, and after the other envelope portions (Attack and Decay) have been cycled through.

Sync: Provides a way for you to synchronize the device with something else. For example, LFO sync in synthesizers often allows you to clock the beginning of the LFO cycle to key-on timing. Sync is used in the Roland x0x series to allow both sequencers to start at the same time with the same tempo.

Timbre: In certain Roland synthesizers, a building block in the patch. Also a way in describing the tone quality of the sound.

Tracking Generator: A synthesizer feature found on Oberheim and Alesis synthesizers. Here is a long explanation, thanks to Analog Heaven's archives:

The tracking generator is a non-linearizer for control signals. Imagine the
range of a controller as a line from minimum to maximum:

^      ^      ^      ^      ^
(sorry for the rough ASCII graphics) 

Anyway, imagine this line as being a broken rubber band stretched between two thumbtacks, one at each end. (I indicate where they go with tilde marks '~' in the above picture.) Now insert three more tacks into the band, one at the center and two more halfway between the center and the ends. So you have a line of five tacks describing the straight line of the controller range, with zero effect at one end and maximum effect at the other, right? (The caret marks '^' show the horizontal positions of the five markers.) Well, the tracking generator lets you grab any of those tacks and move it up or down from zero to maximum, stretching the band out of shape and turning it into a zigzag, a quasi-envelope structure, or whatever. Each point on the curve has a value from 0 to 63, and values are set independently for each point. The default, the ordinary unaltered line, has these values:

^      ^      ^      ^      ^
0     15     31     47     63
We could also draw a curve like this:
      ~             ~
      / \           / \     
     /   \         /   \
    /     \       /     \   
   /       \     /       \  
  /         \   /         \ 
 /           \ /           \
~             ~             ~
^      ^      ^      ^      ^
0     63      0     63      0
Or like this:
^      ^      ^      ^      ^
0     15     31     31     31
Or even like this:
^      ^      ^      ^      ^
0      0      0      0     63
Well, what are these curves good for? Remember, they control what happens to a control signal that's normally linear. So you can take a linear signal and use it in different ways by routing it through the tracking generator first. The two-bump example can be applied to a stage of an envelope to create double-tonguing effects. The flattened line can be applied to a mod wheel output to give it a quasi-logarithmic throw. And the last example can be applied to a voltage pedal to produce a footswitch-like 'step' when the pedal is pressed all the way down (ideal for simulating a hihat). And there are lots of others as well. Experiment!

Transpose: A function that allows you to shift the entire keyboard up and down a key. Usually, the transposition is done in semitones (or one note in a key; ie, +1 transposition would make a C a C#, a C# a D, etc.).

Track: On tape, a band of tape used for recording audio. Normal stereo cassettes, for instance, have 4 tracks (2 tracks for each side, one track for each stereo channel). In a sequencer, this refers to a similar concept: A selection of music that can be recorded, sequenced, and played back separate from the other tracks.

Tremelo: A periodic change in amplitude (unlike vibrato, which is a periodic change in frequency).

Tune: A way to adjust the sound of the synthesizer. Early analogs required you to tune through an analog knob, sometimes tuning each individual VCO; most of today's modern digitals, in contrast, allow you to tune with a menu, and usually express the tuning in terms of +/- cents off of the standard tuning.

VCA: Also known as Voltage Controlled Amplifier, this is an amplifer whose magnitude can be controlled by voltages. IE: Attaching the voltage of an envelope will produce a patch whose volume corresponds to the envelope shape; attaching the gate voltage, on the other hand, will produce a patch whose volume goes on when the note is struck and off when the note is released.

VCF: Also known as Voltage Controlled Filter, this is a filter whose cutoff frequency can be controlled by voltages. This means that attaching the voltage of an LFO to it will produce wowing sweeps; attaching an envelope voltage will give the filter a particular shape; etc.

VCO: Also known as Voltage Controlled Oscillator, this simply means an oscillator whose pitch is controlled by a certain control voltage. IE: Attaching an LFO voltage will produce a pitch that goes up an down.

Velocity Sensitivity: A measurement of how fast each key is descending.

Vibrato: A periodic change in frequency. Sometimes used as a term for an LFO, specifically a fixed LFO set at a certain speed designed to perform vibrato-like effects.

Wave: A basic sound coming from an oscillator, or another name for a sample.

Waveform: The generated signal produced by an oscillator or a looped sample.

Waveshape: The shape of the wave being produced, usually referring to oscillators. Common oscillator waveshapes are square waves, pulse waves (square waves whose width is controlled somehow), sawtooth (ramp) waves, triangle waves, sine waves, and random / noise waves. The shapes look like (in rough ASCII form):

	      	    	Square		Pulse		Sawtooth (Ramp)
		     ----  --        --     -         /|
                     |  |  |         ||     |        / | /
                    --  ----       --  -----        /  |/
			Triangle       Sine           Noise (random)
                       /\           /-\          \  /. : .
                      /  \  /      |   |   |      :\./ /: \
                     /    \/    \_/     \_/      /. -0_/ : :  


White Noise Unfiltered noise.