Kurzweil K2661 Musician's Manual page 545

Two-parameter Shaper (2PARAM SHAPER)
This function is similar to the SHAPERs described above, but it has two control-input pages
instead of one. The F1 EVN control parameters enable you to add distortion to sine wave
partials that are even harmonics of the input signal, and the F2 ODD control parameters let you
add distortion to sine wave partials that are odd harmonics of the input signal.
In simpler terms, the control parameters behave like those of the regular SHAPER, but they can
shape the signal about six times more than SHAPER can. 2PARAM SHAPER works by
separately multiplying the input signal by the combined values of the two sets of control
parameters, adding the resulting signals, and multiplying that sum by a constant, then
wrapping the signal values that exceed positive or negative full scale (see the WRAP function
below).
Experimentation is the key here. Start with very low values for each of the Adjust parameters,
and increase them until you begin to hear an effect. Some values will create a DC offset (see
diagram below) in the signal—that is, the signal won't oscillate around the normal zero-point of
the scale, but will be shifted toward positive or negative full scale. This may cause a click or
thump in sounds with rapid attacks, decays, or releases. To reduce the click or thump, you can
edit the AMPENV to produce a more gradual envelope.
2PARAM SHAPER works best with the single-cycle waveform keymaps (IDs 112—166).
Figure 16-5
Waveform Wraparound (WRAP)
The next three graphs show the effect of various amounts of WRAP on a sine wave.
0 50 100 150 200 250 300 350
1
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1
Adjust = -30
+ full
scale
- full
scale
SAWTOOTH WAVE
DC Offset
400 450 500 0 50 100 150
1
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1
Adjust = -20
+ full
scale
- full
scale
SAME WAVEFORM WITH
NEGATIVE DC OFFSET
200 250 300 350 400 450 500
1
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1
DSP Functions
The DSP Functions
0 50 100 150 200 250 300 350
Adjust = 0
400 450 500
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