The Kyma Language for Sound Design, Version 4.5

will output 256 tracks on each frame. § We want to sample only one of those tracks and we want to do it
once per frame. So we sample one value and hold onto it for the next 255 samples until the corresponding
value on the next frame. The only remaining piece of the puzzle is which of the tracks to read and how to
offset the SampleAndHold to pick that track on each frame. The formula for this is
(256 - 3) samp
where you would substitute a different number for 256 if you were using a different LowestAnalyzed-
Freq.
Finally, double-click track voice to see the parameters of this Oscillator. Notice that the Frequency parameter
is set to
freq track R * SignalProcessor sampleRate * 0.5 hz
This is one of the few examples that uses an R to get the right channel of a pasted Sound rather than the
left channel. That’s because the frequency envelopes are on the right output channel of the LiveSpectralAnalysis,
and the amplitude envelopes are on the left channel.
The rest of the Sounds in this row and the next use the harmonic analysis method for tracking the frequency
of the input (but could just as well have used the FrequencyTracker module). Try playing some
(or all) of them and take a look at the ones that interest you in order to see how they were put together.
Decision Thresholds and Logical Comparisons
So far, we have been using parameters extracted from the audio signal as something like continuous controllers.
It’s also possible to use them in a way analogous to discrete switches or gates. The key to turning
the continuous envelopes into gates or switches is to use a Threshold or one of the comparison operators.
For an example of using the Threshold on an amplitude, look at trigger a sample on S. This Sound is the
same as the Highs to lows example, except that it feeds the ratio of high to low energy into a Threshold.
When the ratio of highs to lows gets above a selected value, the Threshold output is one. At all other
times, the output of a Threshold is zero. By pasting the Threshold into the trigger field of a Sample, you
can trigger the sample whenever the ratio of highs to lows exceeds the selected threshold. In this case the
threshold is set such that it triggers on the “S” sounds at the beginning of “so” and the ending of
“essence”, but does not trigger at any other time.
You can also make decisions based on the frequency of the input. For example, take a look at pch selects
eq. This is a StereoMix2 with two GraphicEQ inputs. The scale on the first input is
((22050 * freq L) gt: !Freq nn hz removeUnits) smoothed
and the scale on the second input is
((22050 * freq L) le: !Freq nn hz removeUnits) smoothed
First the FrequencyTracker is scaled to the full range of frequencies using
(22050 * freq L)
You probably noticed that it is missing the units of hz. Since this is not a frequency field, we don’t need to
include the units.
The second half of the expression
!Freq nn hz removeUnits
allows you to set a pitch in terms of note number using !Freq, converts the note number value to hertz,
and then removes the units from the number, since we want to compare this number to another number
that does not have units. (The MIDIMapper is scaling the range of !Freq to between 12 and 127 in this
example).
§ The number of tracks per frame associated with each LowestAnalyzedFreq value are:
1F: 512 2F: 256 3F: 128 4F: 64 5F: 32
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