The Kyma Language for Sound Design, Version 4.5

Generating MIDI
If you want to turn MIDI key number into a signal, you have to divide it by 127 in the Value field of the
Constant (because the Constant takes values between -1 and 1), and then multiply by 127 nn in the parameter
field where you actually use the result. For example, look at the way MIDI pitch is turned into a
signal and then mapped to a pentatonic scale using a Waveshaper in the Sound called double pentatonic.
Try playing the Sound called output random MIDI events and adjust the faders in the virtual control
surface. Double-click on it to edit and look at the parameters of events. The Gate parameter is:
1 bpm: (!Rate * 1000)
which generates a trigger at a rate of (!Rate * 1000) beats per minute. The Frequency parameter
!Pitch + ((((1 bpm: (!Rate * 1000)) nextRandom * !Jitter * 7)) of: #(0 1 2 3 5 8 13)) nn
is a bit more complicated, so let’s break it down into sub-parts. We can paraphrase it as
!Pitch + nn
and then break down as
of: #(0 1 2 3 5 8 13)
In other words, we compute an index, and then use it to look up the value stored at that position in the
array: #(0 1 2 3 5 8 13).
The result is that we will add 0, 1, 2, … or 13 half steps to whatever pitch is being played on the keyboard.
Now, how do we come up with ? We can look at as
nextRandom * !Jitter * 7
In other words, at some number of beats per minute, generate random numbers between -1 and 1 and
multiply them by !Jitter * 7. We multiply by 7 because there are seven entries in the array. Multiplying
by !Jitter allows us to control how much variation there is in the random index generator.
Finally, is
1 bpm: (!Rate * 1000)
The first number is the trigger or gate for turning on and off the metronome. Since it is a constant 1, the
metronome will stay on all the time. The rate of the metronome is going to be between 0 and 1000 beats
per minute, depending upon how you have set !Rate in the virtual control surface.
Extracting Parameters from Audio Signals
Once you have started down the path of pasting Sounds into the parameter fields of the MIDIOutput-
Event, another idea immediately suggests itself: what about taking some of the “analysis” Sounds, the
ones that track various parameters of audio input, and converting those to MIDI output events?
Tracking Amplitude Envelope
For example, play the Sound called track the pulse, and listen to the effect of different settings for
!Thresh in the virtual control surface. (This works best with a staccato or percussive patch setting on
your external synthesizer).
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