Lexicon PCM 80 User Manual page 10

PCM 80 Vocal Fix User Guide
The PitchCorrect
Algorithm
2-2
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 80 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 following pages contain diagrams of the reverb and the pitch shifting
portions of the Pitch Correct algorithm, along with a complete parameter matrix
and descriptions of the Pitch Correct parameters. Refer to the PCM 80 User
Guide for detailed descriptions of all other effect parameters.
The Pitch Correct 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 80
MIDI IN jack, set the keyboard and the PCM 80 to the same MIDI channel, and
you're ready to start. Don't try to play the melody note-for-note — just [ress 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.)
Lexicon