On an Analogue synthesizer, changes which occur throughout the dura-
tion of a note are controlled by a section known as an Envelope
Generator. The KS Synth has two main Envelope Generators. The cir-
cuit of one of these is always connected to an Amplifier, which controls
the Volume of the sound when a note is played.
Note that there are no controls in a section on the front panel which
deal with the Amplifier directly. The only way to hear and control an
audio signal passing through the Amplifier is to modulate it by using
Amp Envelope controls.
Each envelope generator has four slider controls which are used to
adjust the shape of the envelope.
When controlling Volume, these controls adjust the following phases of
the Envelope as shown in the illustration.
Attack Time
Adjusts the time it takes when a key is pressed for the envelope to
climb from zero to full volume. It can be used to create a sound with a
slow fade in.
Decay Time
Adjusts the time it takes for the envelope to decay from full volume to
the level set by the Sustain control while a key is held down.
Sustain Level
This is unlike the other Envelope controls in that it sets a level rather
than a period of time. It sets the volume level that the envelope remains
at while the key is held down, after the Decay time has expired.
Release Time
Adjusts the time it takes when key is released from the Sustain level to
zero. It can be used to create sounds that slowly fade away in volume.
A typical synthesizer will have one or more envelopes. One envelope is
always applied to the amplifier to shape the volume of each note
played. Additional envelopes can be used to dynamically alter other
sections of the synthesizer during the lifetime of each note.
The KS Synth has a second main Envelope Generator called the Mod
Envelope which may be applied in various interesting ways. For exam-
ple, it may typically be used to modify the filter cut off frequency or
change an oscillators pitch during the lifetime of a note.
A third Envelope Generator called Envelope 3 is also used by the KS
Synth for specialised purposes (such as FM control). Unlike the other
two main Envelope Generators, this Envelope only has Attack and
Decay phases.
When Envelope 3 is selected by using the Envelope
SELECT button, the same front panel section is used
as for the Mod Envelope (as shown above), but only
the ATTACK and DECAY sliders can be used.
It is possible to make the Envelope settings vary according to how hard
a note is played on the X-Station keyboard. Notes struck with a good
deal of force (velocity) will produce more dramatic changes than notes
played lightly.
The VELOCITY slider in the Envelopes
section controls how the envelopes
respond to note velocity.
Note that there is only one slider which
shared by all three Envelopes. Use the
Envelopes SELECT button first to select
which envelope this slider will control.
SYNTHESIS TUTORIAL
Envelopes And Amplifier
• 34 •
To Next Page
Loading...
