ART Pro Audio DMV-Pro - Dual True-Stereo Effects Processor - Manual (Page 54)

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LFO SHAPES (two cycles each)
EXPONENTIAL
The Exponential waveform is not available
on Tremolo and Panner effects.
SINE
TRIANGLE
RECTIFIED SINE
These graphs are of the available LFO shapes for Chorus, Fanger,
Phaser, Tremolo, and Panner effects. The large choice of waveforms
will allow you to select the best possible shape for most applications.
Some may sound bizarre while others sound natural.
If the LFOs are used for time modulation effects (Chorus, Flanger, and
Phaser), the vertical scale shows short to long delay time moving from
bottom to top. When used for amplitude modulation effects (Tremolo
and Panner), the vertical scale shows low to high audio level while
moving in the same direction.
When you compare the each waveform's effect on sound, listen to the
transitions in the top and bottom areas. This is where the differences
are most audible. Some of the waveforms will seem to slow as the
limits are reached, others will seem to rip right through the transition.
Unfortunately, the visual representations of the waveforms don't
always correspond to the expected sound. For example, when the
Exponential waveform is used with a flanger, the effect sounds smooth
and equal, even though its shape looks lopsided (it moves slowly
towards the bottom and quickly towards the top). This phenomenon
occurs because frequency changes at a logarithmic rate (the number
of frequencies double for each higher octave). The Exponential
waveform moves quicker at the high part of its shape and therefore
can sweep through the distantly spaced high frequencies at what is
perceived as a steady rate. The Exponential waveform, by the way,
would look linear (straight) if it were plotted on a logarithmic
(frequency) scale.
If the preceding paragraph sounded confusing, don’t worry–it just had
to be mentioned. The best way to understand the effects of the
different LFO shapes is to try each one with each effect and note the
difference in sound. You will probably find some interesting (and
unexpected) results.