Draft of a Synthesizer FAQ (Part 2/5)

[Soundwave [Chad Gould]]

V. What do all the synthesizer components mean?

Knowing what type of synthesizer you are looking for is nice in itself. But
what do all of these terminologies mean? NOTE: See VI. Part E for effects
terminology. Effects I consider a feature of the synthesizer, not the
synthesizer itself.

The Glossary

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. Coincidentally, 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 concept 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.

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: 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.

Resolution: 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.

VI. Vocabulary: What all the terms in a synthesizer mean

Beyond what actually produces the sound (the signal generators) described
in section V, here is a list of what you can expect when you look at a
keyboard specification list. What does all those things mean? Here's where
you find out.

Voices / Polyphony / Multitimbral: Voice terms

First, some simple terminology:

Combination Mode: A mode where several "program mode" patches are spanned
through various sections of the keyboard, and combined through one FX unit.

Monophonic: A synthesizer that can only play one note at a time. This is
not necessarily a bad thing; these synthesizers often have very rich sounds
for their lack of voice abilities.

Multi Mode: A mode in some sample-based synthesizers that allow you to play
multiple programs at once (usually 16, the number of MIDI channels
available). Generally, all the multi mode programs use patches created or
called up in program mode, and are all routed through the same FX unit.

Polyphonic: A synthesizer that can play more than one note at a time. Not
necessarily multitimbral, though.

Polyphony: The maximum amount of notes a synthesizer can play at one time.
Of course, a note could contain more than one oscillator. Confusingly
interchanged with voices; it is advisable, before buying a synth, to find
out whether the polyphony listed describes the amount of notes played with
a typical patch, or whether the polyphony listed decreases with a typical
patch.

Program Mode: The mode where the basic building blocks of a synthesizer are
created. Each patch in "program mode" is usually very basic.

Unison Mode: A monophonic mode on some polyphonic analog synthesizers used
where all of the oscillators of the synthesizer are triggered on the same
note, creating a nice fat sound.

Voice: Two ways it is used: 1) An oscillator played in the synthesizer, and
2) The maximum amount of oscillators a synthesizer can play at one time (as
in 32 voices). Sometimes confusingly interchanged with polyphony.

A special note on voices, combo modes, and multi modes

Most modern sample-based synthesizers are patterned largely after the
hugely successful Korg M1 and 01/W. These sample-based synthesizers defined
how future sample-based synthesizers worked. But, as a result, they often
confuse people, fooling them because of the way they are set up.

Modern synthesizer are often set up into three modes: "Combination" modes,
"Program" modes, and "Multi" modes. The building block around all of this
is a program mode patch. These basic patches consist of the basics
(oscillators, filters, etc.), and are accessed via the "program mode".
"Multi mode" is a mode designed for sequencers. In this mode, you can play
multiple patches of "program mode" banks, each on a separate MIDI channel.
By using a sequencer to control each MIDI channel, you can create a
composition simply by using this method. However, most synthesizers only
come with one FX box (with one-four chained FX) that you have to route all
multi-mode patches through. "Combination modes" are more geared towards
playing the keyboard solo - they take several patches created in "program
mode", span them across various layers of the keyboard, route them through
1 FX box, and create a very lush patch (with less polyphony, and no ability
to do multimode-style sequencing unless the keyboard has a "combination
copy". They're good for demonstrations though.)

A warning: Any changes made to program mode patches will often affect the
combination mode patches! If you like your combination mode patches, be
careful. Because combination patches are harder to play in multi mode
(although many synthesizers contain a way to copy them over), I usually
ignore them myself. (: Also, the terminology on some synthesizers may be a
lot different (I'm using Korg 01/W / X3 / X5 terminology), but the basic
gist is the same.

RAM and ROM

Memory is a critical part of today's synthesizers. Memory is used to store
patches, both presets and user-defined patches. An important part of
today's synthesizers, therefore, can be how many ROM presets it has. The
more ROM space it has, the greater amount of space the synthesizer has to
store preset samples. Of course, the quality of samples is more important
than the quantity, but it may give an indication of how many ROM samples
are in the synthesizer.

RAM is critical for any samplers. RAM is where all of the samples are going
to be stored. Early samplers often used proprietary RAM chips to store the
samples in - a pain in today's market. Fortunately, most samplers nowadays
can handle SIMMs. SIMMs are exactly the kind of memory chips that you find
in your local computer store. Of course, SIMM requirements vary from
sampler to sampler, and you may not like the idea of opening up your
sampler to install the SIMMs to begin with... in which case you see your
local dealer for memory upgrades.

Of course, there's also patch memory, the place where synthesizers store
the settings of the synthesizer patches. This memory can either be RAM
(user-modifiable patches) or ROM (preset patches). And, of course, there is
memory for modifying the global settings of the synthesizer. Most
specification lists give the number of patches available, and how many of
them are preset ROM (unmodifiable) and user-modifiable RAM.

Most synthesizers have a memory protect mode, FYI, that must be turned off
before you begin modifying patches. Usually, when you turn the synthesizer
on, memory protect mode defaults to on so you don't accidentally overwrite
your favorite patch when playing around.

Packaging: Rack mount vs. Keyboards

When it comes to packaging, there are two basic models that today's
synthesizer comes with: Either it is sold with a keyboard, or the
synthesizer is mounted in a rack unit. Some music items are sold as a
"tabletop" unit (ie, most drum machines); these items come in a small,
compact box instead. There's not much to be said about that package (except
that, like the rack, it sometimes requires external input from a MIDI
source). However, the keyboard and the rack have some considerations in
mind.

For the keyboard, the following distinctions are important:

* Number of keys. A piano sized keyboard is 88 keys. Most synthesizers seem
to be 61 keys (5 octaves), in contrast.

* Size of keys. Almost all synthesizers nowadays are sold with "full-sized
keys", but portables often come with "half-sized keys", which are not as
large (and more compact).

* Action. These determine exactly how the keyboard feels to your touch. The
three categories in this field are weighted, synth-action, and
semi-weighted. The distinctions are as follows:

* Weighted keys make a great attempt to feel like a piano (which, since the
key is pulling on a lever to strike a hammer, feels weighted down). They
are often loaded with various mechanical devices to simulate the piano
action, and might be best for those used to playing on a piano. In my
opinion, they are more expressive, but difficult to do fast solos with.

* Synth action keys have no weighting at all. In other words, they feel
exactly like organ keys: Just there, with no weighting at all. They are not
as expressive to me (but I grew up as a piano player...), but they make it
very easy to play lightning fast solos. The cheapest keyboard option.

* Semi-weighted action is a compromise between the two. While the keys may
be weighted down somewhat to help on the expressiveness, the feel is a lot
different from a piano, and may be alright for fastness. It's also a lot
cheaper than fully weighted keys.

* Zones. Some synthesizers offer the option to be able to transmit various
portions of the MIDI keyboard on different MIDI channels. This makes it
convenient if you hook the keyboard up to an electronic instrument that
supports more than one patch at once (a multitimbral keyboard): You can
easily set it up so half of the keyboard is playing a piano, and another is
playing a saxaphone, or other combinations. Not all instruments support
zones.

For the rack-mounted unit (also known as a module), there are a few
considerations that you have to be aware of. First of all, a rack mounted
unit generally cannot be directly controlled (by a sequencer, etc.) - it
usually is able to be externally controlled by either a MIDI keyboard or a
sequencer. So rack-mounted units are not good for those who do not already
have a keyboard. However, they do take up a lot less space.

Almost all synthesizer units use the conventional rack definition. The rack
for these synthesizers are 19" wide, with at least 1/2" on each end
reserved for mounting on the rack rails. For height, each synthesizer uses
the U specification, where 1U is equal to an instrument that's 13/4" in
height. (And, consequently, 2U instruments are 31/2" in height, etc.) Some
instruments are considered to be 1/2U, where the instrument only takes up
half of the width (ie, 91/2" wide) while still being 13/4" in height. There
is no standard for depth.

Commercial rack-mount boxes are available from SKB and other companies; it
is cheaper to build your own, however, if you have the skills. Some
companies sell rack-rails that allow you to build the box yourself with
little effort; the commercial rack-mount boxes tend to be better, though,
for transport. Your mileage may vary, of course.

Controller terms including basic MIDI

Aftertouch: A control feature of the synthesizer that allows you to
generate additional effects by pressing on the synthesizer key after you
have released a note. Sometimes the effect is subtle (a little more
vibrato, for instance); other times, it's quite noticeable (if the
aftertouch is applied to the filter, for instance).

Breath Control: A device that allows you to blow air through it to produce
various effects when connected to a synthesizer. A way of producing more
realistic wind instruments.

Channel: Or MIDI Channel. Each MIDI cable has 16 channels which a
synthesizer can transmit and receive data on them. One must match the
channels in the external device to the channels in the synthesizer to get
the correct data.

Channel Aftertouch: Aftertouch that is applied to ALL notes on a given MIDI
channel, instead of each note having a separate aftertouch value.

Channel Pressure: Same as channel aftertouch.

Continuous Controller: Used to describe pedals that have a range to them
(such as pedals that control the volume of the synthesizer). The pedal
transmits data within a certain range (such as 0-127).

CV: Control Voltage, a way of controlling older analog synthesizers
externally. Usually used to determine the pitch of a synthesizer. Usually
set to a particular value. See Section VII Part E for a full explanation.

DIN / Sync: Early Roland instruments used this protocol to control their
synthesizers. See Section VII Part E for a full explanation.

Footswitch: A little pedal that can be pressed up or down, either being on
or off. Think of it as like a piano pedal. It is usually used for sustain,
although it can be used for many other features.

Gate: Another way of controlling older analog synths externally; it is
either on or off. Usually used in conjunction with control voltages (CV) to
determine when a note got turned on and off. See Section VII Part E for a
full explanation

Glide: See portamento.

Legato: Not a feature, but a vocabulary word. (: When you are holding down
a note before you hit the next note and release it, you are playing legato.

MIDI: A communications protocol that allows one instrument or device to
control another instrument or device. But it's more than that; this FAQ
devotes an entire section to it! See section VII.

MIDI Clock: A timing reference sent out by MIDI cables; can be used to
coordinate devices together.

MIDI In: These inputs get connected to a MIDI Out port of another device to
receive data from that MIDI Out port.

MIDI Out: These inputs get connected to a MIDI In port of another device so
that the keyboard can transmit data to it.

MIDI Thru: These ports mirror (somewhat exactly) what is received via the
MIDI In port, so the keyboards can be "daisy chained" to a certain extent.

MTC: MIDI Time Code, a way of transmitting SMPTE timing data over a MIDI
cable for synchronization.

Modulation Wheels: A wheel that you can control to produce a certain
effect. Unlike pitch wheels, which center in the middle, these wheels
usually center at 0 (for no effect). Most often used for vibrato, but can
be used for many other things as well!

Multisample: To use several samples, spanned across various portions of the
keyboard, in one patch. This creates a more realistic sound.

Omni: In this mode, the instrument is able to receive in all MIDI channels
simultaneously.

Pedal: Unlike pianos (whose pedals are described as "footswitches"), this
usually describes a pedal that transmits amounts in a certain range (0-127,
for instance), for purposes such as controlling volume (or other things).

Pitch Bender: A little wheel that exists on most synthesizers. By raising
and lowering the wheel, you can raise and lower the pitch. These pitch
bends can even be recorded and played back via MIDI. Neat, eh?

Polyphonic Aftertouch: Aftertouch which is applied to each individual note,
as opposed to channel aftertouch (aftertouch applied to only one channel).

Polyphonic Pressure: See polyphonic aftertouch.

Portamento: A function where the pitch will slide over smoothly from one
note to another instead of jumping over the pitches.

Pressure: Same as aftertouch.

Ribbon Controller: A special type of controller where placing your finger
on a specific portion of a thin "ribbon" (an electrically sensitive strip)
to send controller information to the synthesizer.

SDS: The MIDI Sample Dump standard format. A convenient way of transmitting
samples over MIDI to be exchanged with other samplers.

SMDI: SCSI Music Data Interchange. A specification for sending SDS samples
over SCSI.

SMPTE time code: Stands for Society of Motion Picture and Television
Engineers. A type of code used for synchronizing film and video tape to
audio tape. Often used nowadays to synchronize MIDI machines and tape deck
recorders as well.

Staccato: Another pure vocab word. (: Releasing all notes before hitting
the next note.

Sustain: As in a piano, a sustain pedal holds down (sustains) the notes as
if you were holding them on the keyboard, until the pedal is released.

Sweep Inputs: See continuous controller.

Trigger: Yet another way of controlling older analog synths externally;
similar to gate.

Velocity: How hard you hit the keys. Some keyboards are able to interpret
velocity sensitivity; some are not.

Vibrato Wheel: Sometimes used for Modulation Wheel.

Features (and stuff that wont fit elsewhere)

1/8" Plug / Jack: Same as the 1/4" plug/jack, only the diameter is 1/8"
instead. Used mostly for consumer applications (such as headphones).

1/4" Plug / Jack: The standard synthesizer connection. A large piece of
metal that has a nice bulb-shaped tip on the end, that (guess what!) is
1/4" in diameter! Can either be two-conductor (unbalanced, mono) or
three-conductor (balanced, mono or stereo).

AC Adapter: A little (hah!) cube that plugs into both your synthesizer and
your power plug. This cube converts AC power into the DC power that
synthesizers prefer. It also takes up valuable space on your outlet.

ADAT: An 8-track digital audio tape (DAT), popularized by Alesis.

Aliasing: A phenomenon that occurs with digital recording; above the
Nyquist frequency, frequencies will get distorted into frequencies that
aren't even there.

Arpeggiator: A type of audio device which cycles through the notes you are
holding down on the keyboard in a specified fashion. There are numerous
types of arpeggiators, each with several features that can be useful for
improvisation concerts.

Balanced: Audio engineering term. The two legs of the circuit (+ and -) are
isolated from the circuit ground by exactly the same impedance. Each leg
may carry the signal at exactly the same level but with opposite polarity.
They are usually used with either XLR or 1/4" connectors, and are good for
preventing noise over long distances.

Card: A plug-in memory device, usually used for storing patches. ROM cards
generally have no battery, and you can't write patches to it; RAM cards
generally have a battery, and you can write patches to it. There are other
card types available, though; one company offers a synthesizers, for
instance, that has plug-in filter cards!

Cassette Backup: Many older synthesizers have a way of backing up the
patches to tape, usually through some sort of DIN connector that came with
it that hooks up to the microphone input and the earphone output.

Chorus: A style of effects. Used to fatten sounds up by rotating a portion
of the sound on one channel out of phase.

Clipping: On a sampler, a sample whose volume is beyond the limits of the
sampler's ability to pick it up. The sample is simply recorded at the
maximum volume, or clipped.

Crossfade: This function in samplers blends a given amount at the beginning
of the loop into an equal amount at the end of the loop, thus making some
harsh loops sound nicer.

Cross-synthesis: An effect that allows you to analyze one sound, mix
another in, and produce a combination between the two.

DAT: Digital Audio Tape. A common way of recording things; its like an
audio tape, only the recording is digital.

Data Dump: Section VII Part B.3 explains this term fully. Basically, a way
of backing up patches over MIDI.

Decibel (dB): For reference, a unit of measuring the audio signal. The
greater the dB, the higher the signal. Its a logarithmic scale, so the
ratio between 120dB and 130dB is higher than the ratio between 110dB and
120dB.

Delay: In effects, an echo that occurs with a certain period (greater than
50ms, usually) between the original signal and the echo source. The canyon
effect ("HELLO? Hello? hello? h...")

DIN: A type of connector used heavily in synthesizers. It's a little round
connector that contains a certain amount of pins. MIDI connections, for
instance, are all made with 5-pin DIN connectors.

Digital Output: A special output allowing the synthesizer to communicate
with other digital machines with the same digital outputs in a digital
manner (ie, not first converted to an analog wave). The theory being that
going all digital will result in no noise developing.

Disk Drive: A device that allows you to insert magnetic disks in it to save
various information (such as patches, sequencer data, etc.)

Distortion: An effect that distorts the sound, giving it a grungy feel.
Think of a heavy metal guitar sound. (:

Dry: A signal without effects.

Echo: Another way to describe a delay.

Effects: Signal-processing devices that enhance the sound through a variety
of techniques. Usually contains such features as reverb, chorus, digital
delay, phasing, flanging, etc. In modern synthesizers, there is a certain
number of FX algorithms (effect types) in them, with up to a certain number
of simultaneous effects (effects that can be played at once). More is
better, in many ways (although FX quality widely varies).

Equalizer: A device that allows you to emphasize (boost) certain
frequencies while de-emphasizing (cut) others. Parametric Equalizer allows
control of both the frequencies being cut and boosted and the gain.

Fade: A function in samplers that allows you to reduce the volume of a
portion of the sample to 0 gradually.

Feedback: A condition where the device is modulating itself. When a
microphone feedbacks, it is picking up signals from a speaker and
modulating that to create that high pitched whine. Other synthesizers use
feedback to create different effects.

Flanger: A type of effect where a portion of the sound is rotated in and
out of phase with another portion of the sound by varying the delay time.
Originally done by creating a tape delay and holding one of the tape loops
against the tape player flanger, hence the name.

Flash ROM: ROM whose data can be recorded. Sometimes used in samplers (in
the form of Flash RAM or Flash ROM cards, etc.)

Gain: In samplers and mixers, often another word for volume.

Groove Quantize: A method of quantizing that is not as exact as
quantization is (but perhaps smarter); allows room for a "swing" beat.

Input: A jack specifically used for inputting sounds or controls into the
synthesizer, to be processed, sampled, etc.

Jack: Not the name, but the electronic device that receives the connector.
Also known as "female" for obvious reasons.

Leslie: A type of effect produced originally by rotating a speaker in a
cabinet. Popularized by Hammond B3s and other organs.

Line Input/Output: An input or output at line level.

Line Level: Technically, a signal whose level falls between -10dBu and
+30dBu. The common level that a synthesizer outputs at.

Multitimbral: A keyboard that can play more than one patch at once. Early
keyboards were NOT multitimbral, and could only play one sound at once,
regardless of the polyphony they had. Nowadays, through sequencers and
MIDI, a keyboard CAN play more than one instrument at once. These keyboards
are called multitimbral.

Normalize: On a sampler, a command that increase the intensity of the wave
to maximum without distortion (clipping).

Numeric Keypad: Just as one would expect, it's a little calculator-like
grid which has all 10 numbers available.

Nyquist Frequency: A theory about digital recording; the theory says that
in order to measure a particular frequency, the sampling rate must be
double of that particular frequency. In other words, it's the highest
frequency that you can record given a particular sampling rate.

Operating System: As if computers were enough, now you find out synths have
operating systems too. (: Really, it's nothing more than the software that
controls the interface and workings of the synthesizer. For today's digital
synths, OS is getting more and more important.

Output: A jack used to deliver the final signal to a mixer or other
keyboard for further processing. Many synthesizers have more than one
output (that can be assigned) for convenience (so you can assign different
instruments to different FX and EQ routings on the mixer, for instance).

Overdrive: A type of distortion that is produced by overdriving the signal
and reducing the resulting volume.

Parametric Equalizer: See the equalizer definition.

Phaser: A type of effect where the phase of an input signal is modulated.
Unlike a flanger, this signal does not rely on a delay, and thus has a
different characteristic.

Phone Plug / Jack: Another name for 1/4" plugs / jacks.

Phono Plug / Jack: See RCA Plug / Jack

Plug: The electronic connector itself. Also known as "male" for obvious
reasons.

Quantize: One of the sequencer options available; rounds the values of the
notes played to exact values (such as eight notes, sixteenth notes). Makes
things exact but sometimes computer-sounding.

Quantization Noise: A phenomenon that occurs in digital samples. If the
resolution is bad enough, with low notes you add partials that don't even
exist.

Quickdisks: An old, proprietary, now outdated format that some older
samplers and synthesizers used for storing data. Not recommended due to the
expense of new Quickdisks in today's market.

RCA Plug/Jack: A very low cost type of connector that is commonly used in
4-tracks and consumer stereo equipment. Not very durable or reliable, but
very cheap. The plugs are immediately recognizable: A small hole surrounded
by some insulating material, with a metal outer shell.

Resample: A function that allows you to change the sample rate of a sample
without changing its overall quality (pitch, etc.)

Reverb: A special FX device that is used to simulate the continuous echo of
a hall, arena, or other echoing type places. Very similar to a delay.

Reverse: A function in samplers that simply turns the wave inside out.

SCSI: Small Computers Interface. A high speed communications protocol that
allows electronic pieces of equipment to communicate to each other. Often
used in samplers for tasks such as storage.

Sequencer: A device or program that allows people to record information
(usually MIDI information) and played back, with possibilities for editing,
quantizing, etc. In the old days, the only sequencers available were
hardware sequencers that played back a limited amount of notes (ie, 16, 32,
etc.) in a repetitive sequence (hence the name). Today's sequencers are
much more powerful in some ways, as you can compose and score entire
symphonies with them. However, they aren't as real-time controllable...

Sostenuto Pedal: A pedal found on some synthesizers in which notes are
sustained only if they are held on the keyboard when the pedal is pressed.

S/PDIF: An interface used to directly connect two digital audio components
together so as to allow them to transmit direct digital audio data to each
other.

Splice: In tapes, a term used for cutting pieces of tape and putting the
two pieces together. Sometimes used in samplers for the same reason.

Split: A mode in which a keyboard is split up between two or more separate
patches.

Step Recording: A way of recording on sequencers that allows you to enter
in notes one at a time.

Swing: In quantization, a parameter that allows leeway for notes that don't
quite fall on the beat, keeping a certain "groove" that may be in a song.

SYSEX: A form of MIDI data used to transmit information exclusive to a
particular synthesizer. Often used for MIDI patch dumps.

Time Compression/expansion: Time compression / expansion is a function used
in samplers to change the speed of the sample without changing the pitch. A
very useful function often heard in a variety of music forms.

Tremolo: A type of effect that cyclically effects the volume.

Trim: In this sampler function, you select a range in the sample;
everything beyond this range gets deleted when activated.

Truncate: To cut off the end of a sample beyond a certain point.

Tuning Tables: A series of programmed tables that allow your keyboard to
achieve various tuning scales. For example, one table could be set for
Arabic tuning, while another could be set for the standard Equal Temperment
scale most Western songs use.

Velocity Curve: A way of setting how the velocity of a struck note on a
keyboard affects the volume of a synthesizer.

Vocoder: A real-time effect commonly used in the late 70s and early 80s.
You plug your synthesizer in one input, and a microphone in another; you
play some notes on the keyboard, and then you speak. Every time you speak,
your voice is combined with the keyboard to make it sound like the keyboard
is talking. A very robot-like effect.

Wah: An effect designed to simulate a "wah" pedal. Think of the
wocka-chicka-wocka effect found on 70s R&B songs. Think Jimi Hendrix.

Wet :A signal with effects.

XLR: A type of connector, commonly seen in microphones. A large,
three-pinned connector is used for a nice balanced connection. First
manufactured by Cannon.

XFade: An abbreviation for crossfade.

Standards (Sample and soundbank)

.AIFF: Audio Interchange File Format. A common standard for transmitting
and playing back sample data.

.AU: Sun's method of transmitting and playing back sample data.

.MID: Also known as the standard MIDI file format. A commonly accepted
format for interchanging sequenced data. Widely used in soundcards for
exchanging songs in the General MIDI (GM) format.

.VOC: Creative Labs popularized this standard for transmitting sound data.

.WAV: A common standard for transmitting and playing back sample data,
popularized by Microsoft.

GM (General MIDI): The original standard for common MIDI files, found on
many keyboards and most soundcards today. Most of the MIDI files
transmitted over the net are in the General MIDI format. It is also a
popular format for game composers, since almost all soundcards can be
worked to be GM. It defines what instruments go where and minimum
polyphony, among other things. Some feel it is too limiting, though.

GS: Roland's extension to General MIDI, a format found on modern Roland
instruments and soundcards. It is designed to be 100% compatible with GM
while at the same time containing extra features.

XG: Yamaha's extension to General MIDI, a format found on all modern Yamaha
instruments and soundcards. It too is designed to be 100% compatible with
GM while at the same time containing extra features.

Front panels (including controlling the synthesizer)

First of all, some definitions for the front panel controls and displays:

Attenuator: A pot that specifically turns down the volume of an input.
Often found on modulars.

Button: You press it and it does something. (:

Knob: Same as potentiometer / pot.

LCD: Liquid Crystal Display. Basically, a panel on the front of the
synthesizer that shows a grid of dots. This grid of dots is used to display
letters, pictures, etc. that show you what patch number you are on, program
information, etc.

LED: Light Emitting Diode. An electronic device that emits a little light
when electricity is passed through it; available in red, green, yellow, or
blue. Like little red light bulbs; usually used as indicators. Also
available in 8-segment number indicators (for that calculator look).

Pin Matrix: You won't see this except on a VCS 3, but I thought I'd throw
it in. (: The VCS 3 used a compact grid that you connect with a series of
pins to substitute for patch chords, creating a semi-modular synthesizer in
a compact unit.

Pot: Not the weed variety. (: Short for potentiometer. A knob that
functions as a variable resistor; but you don't need to know that. All you
need to know is that a pot is what you often are using to control your
synthesizer.

Slider: Another variable resistor, but instead of being a knob that you
turn to control features, you slide a little lever up and down.

With the advent of techno, many people are now concerned with the problem
associated with real-time control. Back in the late 80s, real time control
was not as desired of a feature (the desired feature was
press-patch-number-and-play), but real-time control has come back in vogue.

Older analog synthesizers often had knobs to control the sound instead of a
digital interface (a LCD that shows menus and a couple of buttons to page
through the menus); this is nice for those looking for real-time control.
There are, however, synthesizers that have are analog and have no knobs at
all (The Korg Poly 800, Ensoniq ESQ-1, and Oberheim Matrix 6R to name a
few). And there are a few digitals that have real-time control available
(especially with the advent of techno and its emphasis on real-time
control). So don't assume that, say, a Poly 800 will allow you to make that
nice acid bass-line. (: Today, many newer synthesizers have front-panel
knobs. Many of them are nicer than the old controllers in some respects
(for example, up until recently, the Juno 106 was the only analog
synthesizer that transmitted knob information through MIDI; now there are
many others).

And don't assume that just because it has a LCD and no knobs, it is crap.
Admittedly, real-time control is MUCH more difficult, but you can still get
some nice sounds. I think beginners find it easier to grasp onto something
physical, though - programming a synthesizer through sliders and knobs
instead of paging through menus and changing sounds.
--
Chad Gould aka Soundwave |-X5/D50/DX27S/Juno106/TX16W/BE5-|
internet: cgo...@gate.net |-M1000/Dr550mkII/SE70/MS1402VLZ-|
http://tilt.largo.fl.us/ |Make Happy the Harmonica Happy!!|
"It has to warm up... SO IT CAN KILL YOU!" - Raul Julia, TAF pinball