The Kyma Language for Sound Design, Version 4.5

so that when a MIDI key is down, the duration jumps from 5 seconds to 105 seconds. Play this Sound and
try to hit a MIDI key just at the start of one of the notes.
Play and then take a look at warped time index. Instead of using a FunctionGenerator to generate a full
ramp from -1 to 1, this example uses a WarpedTimeIndex to control the rate of the envelopes. The WarpedTimeIndex
takes two arrays, each containing the same number of time points: the ideal time points
and the actual time points. It creates a multi-segment envelope with different slopes corresponding to
different rates of time: steeper slopes go through the envelopes faster, and shallower slopes go through
the envelopes more slowly. The WarpedTimeIndex slows down or speeds up the resynthesis such that the
actual times occur at the specified ideal times.
Along these same lines, multiseg env on time index uses a MultiSegmentEnvelope generator to generate
the time index. The total duration is broken down into ten segments, and the duration of each segment is
hot, so you can control how long each segment should last using the faders in the virtual control surface
or a MIDI fader box.
Take a look at live freeze frame on key down(4). Look at the parameters of the Sound called capture frame
and loop left. This is a DelayWithFeedback with the Feedback set to !KeyDown and the Scale set to 1
- !KeyDown. Scale is an attenuator on the Input, so this means that when no key is being held down,
the Input amplitude will be at the maximum of 1, and when a key is held down, the Input amplitude
will be cut to zero. Notice, however, that whenever the Input amplitude is set to zero, the Feedback
amplitude will be at its maximum (and vice versa); they are the opposites of one another. So when a key is
held down, there is no new input, and the delay line is recirculating with no loss of amplitude on each
feedback loop. In a way, the DelayWithFeedback is acting as an oscillator whose wavetable is whatever
was captured in the delay line, and whose period is 256 samples — the size of one frame when the analysis
frequency is 2 F (see the parameter settings in nonharmonic analysis). The length of the delay can be
any multiple of the frame length (for example 4096 samp would also work). The left and right have to be
delayed separately, because DelayWithFeedback does a mono mix if it gets a stereo input.
Vocoder & RE Time Scaling
Try the Sound called vocoder time-stretch, and then double-click on it to see how it is put together. First,
look at the GenericSource. Its Frequency is set to
60 nn hz * !Rate
60 nn or middle C is the default frequency given to samples that do not have a single, identifiable pitch.
60 nn (a pitch) is being converted to a frequency (by giving it units of hz). Scaling the frequency of a
sample is the same as scaling its duration: a lower frequency means that you read through the sample at a
slower rate, so the duration is longer.
As you know, however, slowing down a sample also lowers the frequencies of its formants. So this Sound
uses a Vocoder to compensate for that. Double-click on the Vocoder to see its parameters. Notice that
SideFreq is set to !Rate. So whenever !Rate is made smaller (making the sample frequency and formant
lower in frequency), the analysis filter bank is also shifted lower in frequency. However, the
resynthesis filter bank stays at its original frequency (because InFreq is set to 1). Thus, when the sound
is “resynthesized” by passing noise through the Input filters, the formants are at the normal frequencies,
even though the sample is being played back more slowly.
Note also, that the TimeConstant is also scaled by !Rate, because when the sample is slowed down,
any changes in it happen more slowly, so the time constant controlling the amplitude follower can also be
longer.
Try playing 22-vocoder rate & freq scale, and experiment with the fader settings in the virtual control
surface. This is similar to the previous example except that, instead of using Noise as the Input, this example
uses an Oscillator on a buzz waveform with 64 equal-amplitude harmonics.
electric shaver mouth also uses a buzz-waveform Oscillator, but this time as the Input to an RE filter. In
this example !Rate controls the OnDuration of the TimeIndex controlling the rate at which the RE filter
coefficients are updated.
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