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Some Information on Pitch Shifting and Other Stuff…
As we mentioned earlier, it is a bit hard to describe how this thing really works but a
little more detail might be helpful as there are "oddities" involved in pitch shifting
and reverse shifting that are worth noting. Nothing bad, just inherent aspects of the
process that are worth a few words of explanation.
As we stated earlier, a pitch shifter grabs a slice of audio and plays it back at a dif-
ferent speed to create the alteration in pitch. The important thing to know is that in
reality the pitched signal is really being "pushed up" or "pushed down" and modulat-
ed with a kind of saw tooth wave and the farther you move from the original frequen-
cy the faster this modulation occurs. This is sometimes referred to as "glitching" and
is an artifact and byproduct of all pitch shifting algorithms.
It is not just how
far you deviate from the original pitch (shifting up as opposed to
down usually introduces more artifacts) but how
big a slice of the audio you set the
unit to sample that also has some affect on both the speed and depth of the modula-
tion. In addition, the larger the slice the more inherent delay is introduced between
the time the original signal is played and the slice of audio that is played back.
As the
size of the slice increases so does the amount of delay between the original
signal and the playback of the effected signal. But this delay time does not remain
constant due to the modulation that is used in creating the pitch shift. So if you use
a long slice and play a riff, the time between your playing the original riff and the
playback for the effected riff can vary due to the modulation of the effected signal.
Most pitch shifters automatically adjust the size of the slice to keep it constant so
that the effected signal is played back with just a little bit of delay. Crystallizer, on
the other hand, offers you the ability to take
much larger slices of audio, shift the
signal up or down (4) octaves (that’s a lot of shifting!), play the pitch shifted signal
back either in forward or reverse and allows you to feed the output of the shifted sig-
nal back into the input so as the signal repeats it is re-shifted with each successive
repeat. It also provides the ability to tempo lock the playback so that the repeating
signal always starts playing back on the selected beat.
So the important things to keep in mind are the fact that the pitched signal is con-
stantly being modulated, and the larger the slice of audio the longer the inherent
delay between the original sounds and the effected signal, and finally, that this delay
is not always constant.
Содержание Crystallizer
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