Antares Auto-Tune 5, Owner'S Manual

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How Auto-Tune 5 detects pitch
In order for Auto-Tune 5 to automatically
correct pitch, it must first detect the pitch
of the input sound. Calculating the pitch of
a periodic waveform is a straightforward
process. Simply measure the time between
repetitions of the waveform. Divide this time
into one, and you have the frequency in Hertz.
Auto-Tune 5 does exactly this: It looks for a
periodically repeating waveform and calculates
the time interval between repetitions.
The pitch detection algorithm in Auto-Tune
5 is virtually instantaneous. It can recognize
the repetition in a periodic sound within a few
cycles. This usually occurs before the sound
has sufficient amplitude to be heard. Used
in combination with a slight processing delay
(typically about 1 to 10 milliseconds), the
output pitch can be detected and corrected
without artifacts in a seamless and continuous
fashion. (Although it must be kept in mind that
some plug-in protocols introduce a certain
amount of inherent and unpredictable delay.)
Auto-Tune 5 was designed to detect and
correct pitches up to the pitch C6. (If the
input pitch is higher than C6, Auto-Tune 5
will occasionally interpret the pitch an octave
lower. This is because it interprets a two cycle
repetition as a one cycle repetition.) On the
low end, Auto-Tune 5 will detect pitches as
low as 25Hz (when the Bass Instrument Input
Type is selected). This range of pitches allows
intonation correction to be performed on
virtually all vocals and instruments.
Of course, Auto-Tune 5 will not detect pitch
when the input waveform is not periodic.
As demonstrated above, Auto-Tune 5 will
fail to tune up even a unison violin section.
But this can also occasionally be a problem
with solo voice and solo instruments as well.
Consider, for example, an exceptionally breathy
voice, or a voice recorded in an unavoidably
noisy environment. The added signal is non-
periodic, and Auto-Tune 5 will have difficulty
determining the pitch of the composite (voice
+ noise) sound. Luckily, there is a control (the
Tracking control, discussed in Chapter 3) that
will let Auto-Tune 5 be a bit more casual about
what it considers “periodic.” Experimenting
with this setting will often allow Auto-Tune 5 to
track even noisy signals.
How Auto-Tune 5 corrects pitch
Auto-Tune 5 provides two separate and
distinct ways to approach pitch correction:
Automatic Mode and Graphical Mode. The
basic functionality of each is described on the
following pages.