Using the groove machine – Apple Logic Pro 8 User Manual
Page 509
Chapter 21
Editing Audio in the Sample Editor
509
Harmonic
If Harmonic Correction is turned on, you can also use the Harmonic (Shift) parameter to
independently alter timbre. The units are shown in cents—100 cents per semitone.
 If you select the same value in both the Harmonic and Transposition fields, no
correction occurs, and the result is as if Harmonic Correction is switched Off.
 If you set Harmonic to zero, the formants don’t change. This avoids the unwanted
side effects of traditional pitch shift algorithms.
∏
Tip: If you need to find the exact transpose value by trial and error, switch off Harmonic
Correction. As soon as you’ve found the right transposition value, do an independent
Harmonic Correction, with the same value, in a second step.
Shifting Formants Without Transposition
You can also use Harmonic Correction to shift the formants without transposition. This
means you can alter the physical size of the sound source’s resonance body—to give
female voices a male character and vice versa, for example—while keeping the pitch in
tune.
This remarkable effect (sometimes known as gender-bending) allows you to change
sounds so that they appear to have been made by unusually small or large instruments.
It is useful for beefing-up thin or brittle sounding parts, such as guitars, or instruments
and vocals that were recorded through a microphone with a limited frequency
response.
As a usage example on a vocal part: If you set Harmonic Shift to –300, and the
Transposition value to zero, the sonic character of the singer will be changed as though
transposed three semitones down—but without an actual transposition in pitch. This
means that a musical C remains a C, but the timbre of the vocal becomes darker.
Using the Groove Machine
You can use the Groove Machine to alter the feel, swing, or groove of digital audio
material, in percentage steps. Put another way, the Groove Machine can quantize
straight audio!
You can also strictly quantize audio that “grooves a little too much” with the Quantize
Engine (see “
Important:
Before you open the Groove Machine, make sure that the tempo of
Logic Pro exactly matches that of the selected audio material, or the Groove Machine
won’t work accurately. You can, however, set the tempo and length directly in the
Groove Machine, using the Corresponds with Tempo and To Bar Length parameters.
To open the Groove Machine, do one of the following:
m
Choose Factory > Groove Machine in the Sample Editor (or use the corresponding key
command).