Lexicon PCM 81 - REV, User Manual

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3-63
The Algorithms and Their Parameters
The Vocal Fix Pitch Correct algorithm is designed to work with monophonic (one
note at a time) vocal sources. The algorithm contains an intelligent pitch shifter
combined with a PCM 81 Chamber reverb. The intelligent pitch shifter detects
the pitch of incoming audio and produces effects based on the detected pitch.
The reverb follows the pitch shifter in series. The FX Mix parameter is set to 0%
reverb as most applications require only pitch processing.
The algorithm provides a simple, yet powerful, set of tools for correction of
previously recorded melody tracks which are off pitch. The Pitch Detect display
shows the pitch of the input source in real time, displayed as a chromatic note
and ±cents so that you can see exactly where and how much correction is
needed. For most applications correction will only be needed for notes that are
audibly sour.
There are two basic approaches to this type of pitch correction. The first is to
patch the Correct parameter to a switch or to the ADJUST knob, the second is
to use a MIDI keyboard to control correction. The patch method is preferable for
fine tuning a performance, whereas using a MIDI keyboard provides more
flexibility when handling more serious pitch errors, or when it is necessary to
completely rework the melody.
MIDI control is straightforward. Just connect a MIDI keyboard to the PCM 81
MIDI IN jack, set the keyboard and the PCM 81 to the same MIDI channel, and
you're ready to start. Don't try to play the melody note-for-note — just press the
keys needed to correct bad notes. When you press a key on the MIDI keyboard,
the audio is forced to the keyboard's pitch. When you release the key, the audio
is processed according to the settings you have made to Correct and Tracking.
Typically, Correct will be set to 0% and Tracking set to Fastest. This results in
the MIDI note determining the correct pitch and triggering correction on and off.
(By the way, you don’t need a score to know which note, just watch the Pitch
Detect display.)
The Pitch Correct
Algorithm and Its
Parameters