The Kyma Language for Sound Design, Version 4.5

Envelopes
In general usage, the word “envelope” is used to mean some kind of wrapper or enclosing cover around
something else. In some sense, you can think of an amplitude envelope as enclosing or defining a sonic
“event” or discrete “object”.
First, in the interest of preserving your speakers for a little while longer, turn the gain on your amplifier
down. Once your speakers are protected, play the Sound called endless sine. This is the kind of sound
that is quickly relegated to the background. It sounds as if it could be the hum of a machine or a distant
motor; it isn’t changing, so it seems safe to ignore it, and it almost disappears after a while. Putting an
amplitude envelope on the endless sine will give it “closure”, and make it seem like a single “event” or
“object”.
FunctionGenerator
AR and ADSR
To apply an amplitude envelope to any Sound, the method is the same: multiply the Sound by the envelope.
To see an example of this, double-click on apply shape of env to oscil amp. Select Function-
Generator17, and choose Full waveform from the Info menu. A FunctionGenerator reads through its
wavetable exactly once each time it is triggered, so what you see in the full waveform display is a picture
of the Gaussian wavetable.
Leave that full waveform window open, and return to apply shape of env to oscil amp; this is a Product
module. Select it, and choose Full waveform from the Info menu. What you see is the shape of the Gaussian
wavetable applied to the amplitude of the sine wave oscillator. (Actually, it looks more like the
Gaussian shape mirrored across the zero axis, because the sine wave is both positive and negative, and
when you multiply the positive value from the Gaussian curve by a negative value from the sine wave,
you end up with a negative number).
Double-click on a different shape. As you can see, this is the same configuration: a Product with two inputs:
sine wave and ADSR env. Select ADSR env , and choose Full waveform from the Info menu. Then
double-click ADSR env to see its parameters.
An ADSR envelope is based on the idea of an envelope that will be controlled by a trigger. You specify
how long it should take to reach the maximum amplitude when the trigger is first “attacked”, how far it
should “decay” after that initial attack and how long it should take to decay that far, what its amplitude
should be while the trigger is “sustained”, and what the envelope behavior should be when the trigger is
finally “released”. You can see the different parts of the envelope clearly in the full waveform display: the
attack of 0.2 seconds, an initial decay down to 0.75 of the full amplitude over the course of 0.1 seconds, a
flat sustain portion, and finally a release that takes 0.5 seconds.
In this example, the envelope is triggered once and has a finite duration, so the sustain is computed by
Kyma as the total duration minus the sum of the attack, decay, and release durations.
GraphicalEnvelope
Play the Sound called graphic env chopper, and use the MIDI keyboard to select different pitches and get
a feel for how it behaves. Double-click on it to see how it is put together. Notice that there is a configuration
that looks a lot like the last Sound we looked at; it’s a Product with 3 detuned GA saws and
GraphicalEnvelope14 as its Inputs.
Double-click GraphicEnvelope14 to see how it got its name. This Sound has a rubber-band style editor for
drawing the desired envelope shape. When you click in the Envelope field, you should see two little red
arrows. These mark the beginning and ending of a loop. Count the number of spikes or ridges between
the red arrows. Make sure the original Sound is still playing, and hold down a key on the MIDI keyboard.
When you press a key, it goes through the entire envelope up to the left arrow once, then loops between
the arrows as long as you hold the key down, and finally when you release the key, it will go through the
segment after the end-loop arrow. What it stores is not the absolute amplitudes, but the slope of each
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