Synth Glossary 2
ADDRESS : A location in the memory
where a particular piece of data is stored.
ADSR :Attack Decay Sustain Release - the four control elements
of an envelope.
AMPLITUDE MODULATION : (A.M.) The changing of the amplitude level
by a control signal.
ANALOGUE : A signal that is continually variable, e.g. an envelope
control voltage. (See Digital)
APERIODIC WAVEFORM : An unpitched non-repeating waveform.
AR : Attack Release - a basic envelope.
ATTACK : The first stage of a control envelope - the period from
when the note is triggered to when it reaches its maximum value.
BAND PASS FILTER : A filter that removes from a signal all
frequencies apart from those around a set frequency.
BAND REJECT FILTER : A filter that
removes from a signal all frequencies around a set frequency.
CENTRE DETENTE : A physical 'stop' in the middle of a control element's
(knob) travel that enables it to be easily returned to a central position.
CLOCK : Regular low frequency pulse or square wave used for driving
sequencers arpeggiators etc.
COMPUTER INTERFACE : A connection for communication between a
computer and external equipment.
CONTROL VOLTAGE : A voltage used to determine the effect of such
devices as VCOs, VCFs, and VCAs.
CUT-OFF FREQUENCY : The frequency at which a filter is set to
DATA : The information that is processed by a
computer/microprocessor. It is stored in an Address.
DECAY : An envelope parameter -the time taken for the contour
to fall from its maximum value to a sustain level.
DEFAULT : A start-up value for parameter, ie the value given
before any programme specifications have been made.
DIGITAL :The representation of a signal using
numbers. Generally this will be in binary format, whence every value will
consist of a series of '1's and '0's (Ons and Offs).
DYNAMIC RANGE : The amount of control a touch responsive keyboard,
or controller, gives the player.
EMPHASIS : see
ENVELOPE : A one-shot voltage that changes as a function of time,
and is used to shape the timbre and amplitude of a sound.
FEEDBACK : The routing of some of the output of a device back
to its input. In filter terms this results in an increased resonance.
FILTER : A device used to remove specific frequencies from a
FREQUENCY MODULATION : The use of one control device to vary
the frequency of another, e.g. Vibrato is the frequency modulation of a VCO
by an LFO.
GATE : A signal used to trigger envelope generators and other
time dependent devices. It indicates whether a note is being held or not.
GLIDE : The slewing of a pitch from a fixed point to the note
GLISSANDO : The movement of the pitch between two notes in discrete
HIGH PASS FILTER : A filter that removes from a signal frequencies
below a certain set frequency.
JOYSTICK : A performance control mechanism that enables the player
to bend a note (X-plane) and introduce modulation (Y-plane) simultaneously.
LAYERING : The use of more than one sound source per note to
build up a composite voicing.
LFO : The low frequency oscillator, a device that is used to
modulate other parameters at sub audio frequencies (i.e. around 30 cycles
per second or less).
LOW PASS FILTER : A filter that removes from a signal frequencies
above a certain set frequency.
MEMORY : A device for retaining information/data.
MERGE : A combination of sequences.
MODIFIER : A device that acts on a signal to shape its
MULTIPLE TRIGGER : A system whereby a new trigger pulse is generated
every time a new note is played, no matter if others are still being held.
NOISE : A source of random voltage fluctuations.
NOTCH FILTER : see Band Reject
ONESHOT : A single event that has to be triggered every time it is
PERFORMANCE CONTROLS : Specially designed control knobs, switches
etc, that the player uses to physically vary certain parameters of the sound
whilst the instrument is being played.
PERIODIC WAVEFORM : A regular repeating waveform, which, by its nature,
exhibits a pitch.
PORT : An access point, usually on the rear panel of an instrument,
that allows the user to tap into the signal chain, or to inject or retrieve
information or control signals from the instrument.
PORTAMENTO : The continuous slewing of the pitch between two notes.
PRESSURE (or FORCE) SENSITIVITY : A variety of touch sensitive keyboard
that enables the user to generate a control signal by applying differing
degrees of pressure to the key after the note has been played.
QUANTISATION : The rounding off of an analogue signal to the closest
RELEASE : An envelope parameter - the time taken when the note is
released, for the contour to fall from its Sustain level back to zero.
RESONANCE : Achieved by applying feedback
to a filter, the effect of resonance tends to boost the amplitude of those
frequencies around the cut-off point, and as the feedback is further increased
a 'ringing' effect is heard before the filter breaks into oscillation.
SINGLE TRIGGER : A trigger pulse is only generated when all other
keys have been released.
STATIC FILTER : A filter whose cut-off frequency is adjusted manually
using the front panel controls, i.e., it isn't voltage controlled.
SUSTAIN LEVEL : An envelope parameter - the level at which the envelope
settles for as long as the note is held.
SYNCHRONISATION : The locking in of one oscillator onto a harmonic
of another .
TOUCH SENSITIVE : A keyboard or controller that responds to the velocity
and/or pressure with which it is played.
TRIGGER : A pulse produced by the keyboard or controller used to 'fire'
the envelope generators.
VCA : Voltage Controlled Amplifier - a device that controls the amplitude
of a signal in proportion to the voltage applied to it.
VCF : Voltage Controlled Filter - a device that removes unwanted
frequencies from a signal, dependent on the voltage applied to it.
VCO : Voltage Controlled Oscillator - A device generating a periodic
waveform whose frequency is proportional to the voltage applied.
WAVEFORM MODULATION : The changing of the shape of a waveform
by the application of a control signal.
WHEEL : A performance control mechanism, consisting of a plastic disc,
the edge of which is protruding through the panel, and is used for pitch-bend
and modulation effects.