The Kyma Language for Sound Design, Version 4.5

Next is a module named waveform. This is a OscilloscopeDisplay, and it is another type of Sound that
does not have any affect on what you hear — just on what you see in the virtual control surface. It shows
the waveform of its Input as if you were feeding the Input into an oscilloscope, and uses the name of
the Sound (in this example waveform) as the name of the oscilloscope display in the virtual control surface.
Imagine a kind of virtual oscilloscope screen inside the Capybara. The OscilloscopeDisplay writes
its Input on this virtual screen from left to right, until it receives a trigger. Each time it receives a trigger
it starts over again at the left and continues writing the waveform that it gets from its input. As quickly as
it can (but still on trigger boundaries), the host computer reads the virtual display and plots the entire
thing on the computer screen all at once. ‡
So the Trigger input to the OscilloscopeDisplay should be something periodic, something that puts out
a one at the beginning of each cycle in the Input waveform; that way you will always get a picture of
complete cycles of the input waveform and the waveform will not appear to “drift” across the screen to
the right or left because it is out of synchronization with the trigger. The best Sound to do this job is the
PulseTrain, because it puts out a one once per period and is zero at all other times.
Double-click the Sound called trigger to see its parameters. The period of repetition is set to 256 samp.
You can optionally vary the “duty-cycle”, or the amount time during each cycle when the waveform
value is above zero. Try this out right now by checking the VariableDutyCycle box, typing !Duty
into the DutyCycle field, selecting the trigger Sound and choosing Oscilloscope from the Info menu. As
you slowly move !Duty from 0 up to 1, you can see that the width of the “pulse” gets wider and wider.
At the two extremes of 0 and 1, you don’t hear anything, because the value isn’t changing, and sound
does not exist without change. Remove the check from the VariableDutyCycle box before proceeding.
Double-click OscillatorBank74. § This generates a bank of 16 sine wave oscillators. The frequencies and
amplitudes of those sine wave oscillators are supplied from SyntheticSpectrumFromArray18. Doubleclick
on that Sound to see how the amplitudes and frequencies are specified.
A SyntheticSpectrumFromArray takes an array of frequencies and an array of associated amplitudes and
puts them together to create a spectrum for controlling an OscillatorBank or a FormantBankOscillator.
You can optionally associate an array of bandwidths with the spectrum for Sounds like FormantBank-
Oscillator which make use of bandwidth; in this case, though, we have left SendBandwidths
unchecked because an OscillatorBank does not use bandwidth information.
Envelope puts an overall amplitude envelope on all partials; in this case, the overall amplitude is controlled
by !Volume. The value of NbrPartials is arbitrary, but you should generally use a number at
least as large as the value of NbrOscillators in the OscillatorBank; in this example, we are generating
amplitude and frequency values for 16 sine wave oscillators.
Amplitudes, Frequencies, Bandwidths, and Envelope are all hot parameters (indicated by the light
cyan background color in the parameter fields), meaning that you can use Event Values and Sounds as
elements of the array. For example, the value of Amplitudes is:
!F01 !F02 !F03 !F04 !F05 !F06 !F07 !F08 !F09 !F10 !F11 !F12 !F13 !F14 !F15 !F16
an array of amplitudes, each controlled by a fader in the virtual control surface.
‡ Note that although both the right and the left channels of the input are written to the virtual oscilloscope display on
the Capybara, only the left channel is read and displayed on the host computer. You will be able to display both
channels in a future update of the software.
§ By the way, if you are wondering how it got a name like that, here’s the explanation: whenever you drag a Sound
from the prototypes into a Sound editor or Sound file window, Kyma makes a copy of the prototype. When Kyma
makes a copy of the prototype, it appends a number onto the end of the prototype’s name; for example, the third
time you drag an OscillatorBank from the prototype strip, it will be named OscillatorBank3. The current
number for each prototype is stored in the preferences, so it will continue giving you consecutive numbers for as
long as you keep the same preferences file. So, in this particular case, this was the 74th OscillatorBank used by the
person who created this Sound. Kyma tacks the number onto the end of the name to help you distinguish between
this Sound and others of the same class without having to immediately rename it as you are constructing the
Sound. However, you should select the Sound and hit Enter to give it a more mnemonic name as soon as possible.
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