Kurzweil K2600 Musician's Manual page 534

DSP Functions
The DSP Functions
The following three graphs show the effect of WRAP on a sawtooth wave at the same frequency.
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Adjust = -30
With this function you can completely mutilate a sound, and with large amounts of wrap, turn
anything into white noise. At the input of the WRAP function, the signal is multiplied by the
combined values of the parameters on the WRAP control-input page, then multiplied by an
additional gain factor of 30. If the resulting value is greater than full scale (in other words, if itÕs
sufÞciently high to clip), then instead of clipping, the waveform ÒwrapsÓ back around to
negative full scale, and it continues to evolve from that point. Likewise, if the resulting value is
less than negative full scale, it wraps to positive full scale and proceeds from there. For any
waveform, several of these wraparounds can take place before the waveform Þts into the
allowable range.
YouÕll want to try different values of the Adjust parameter to get a feel for the results of different
amounts of wraparound. Look for the value that introduces a very slight amount (it will tend to
be well below 0). The sound will start to buzz here and there, as a few segments of the input
wrap around. As you increase the Adjust value, the buzz will increase, and the pitch of the
sound will begin to disappear. Keep adding to the Adjust value, and youÕll end up with white
noise, regardless of the starting timbre.
The bright buzzy nature of wrapped sounds is due to the discontinuities in the waveforms of the
partials as they wrap around from positive full scale to negative full scale and vice versa. If you
want, you can reduce or eliminate the buzz by sending the signal through SHAPER after it goes
through WRAP (assign SHAPER as the DSP function in the following algorithm block). Set the
SHAPERÕs Adjust parameter to .25. This will map both positive full scale and negative full scale
amplitudes to a level of zero, eliminating the wraparound discontinuities, but preserving the
alterations in the waveform produced by WRAP. SHAPER will add its own effects as well.
The control-input page for WRAP uses the same set of parameters and ranges of values as DIST.
Lowpass Filter with Clipping (LPCLIP)
This is a one-pole Þlter, which is programmed just like LOPASS. The difference with LPCLIP is
that the amplitude of the input signal is multiplied by 4 before the Þlter. This can cause the
signal to clip, which can produce interesting results. Naturally, youÕd use this function only
when you want to induce clipping intentionally as a component of your sound.
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