Modulation Processors
66
Mode
[Symmetric, Asymmetric]
Asymmetric
produces a single curve, extending from –100 to +100.
Symmetric
produces two matching curves extending outwards from 0 to –100 and +100, respectively.
Curve and Mode
Curve
[–100…+100]
This controls the amount of curvature, and whether the curves are concave or convex.
As you can see in the graphic examples, the curve will emphasize certain value ranges, and deemphasize others. For
example, let’s say that you are using a triangle LFO, through Curve, to modulate filter cutoff. If Curve emphasizes high
values, the filter will spend more time at higher frequencies. If it emphasizes low values, the filter will spend more time
at lower frequencies.
Bipolar and Unipolar modulation sources
To understand Curve, it helps to understand the difference between
bipolar
and
unipolar
modulation sources.
Bipolar
sources can swing all the way from –100 to +100, with 0 in the middle. Most LFOs are bipolar, for instance; so
is Pitch Bend. Generally, bipolar modulation sources will work better with the
Asymmetric
mode, but
Symmetric
may
also produce interesting results.
Unipolar
sources only go from 0 to 100, with 50 in the middle. Often, MIDI controllers are unipolar (though you can
also select bipolar versions). Envelopes are usually programmed to be unipolar, even though the Filter and Pitch
Envelopes allow negative levels.
With unipolar sources, it’s almost always better to use the
Symmetric
mode;
Asymmetric
can cause offsets and other
strange results.
Mode
Input
Curve
Result
Symmetric
Unipolar
Positive (+)
emphasizes upper value range
Negative (-)
emphasizes lower value range
Bipolar
Positive (+)
emphasizes both upper and lower value ranges,
and deemphasizes the center
Negative (–)
emphasizes center value range, around 0
Asymmetric
Unipolar
Positive (+)
emphasizes extreme upper range, with offset
Negative (–)
emphasizes extreme lower range, with offset
Bipolar
Positive (+)
emphasizes upper value range
Negative (–)
emphasizes lower value range
+100
0
–100
+100
0
–100
+100
0
–100
Bipolar Triangle Wave
Unipolar Triangle Wave
Asymmetric
(not recommended)
Symmetric
Asymmetric
Symmetric
Curve = 0 (original waveform)
Curve = +100
Curve = -100
