The Pitch Correct Algorithm - Lexicon PCM 81 - REV 2 User Manual

Algorithms and Parameters

THE PITCH CORRECT ALGORITHM

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
InLvl L
L In InPan L
InLvl R
R In InPan R
0 0.0 0.1 0.2
Controls Mix LvlAdjust *InLvl L/R
1 1.0 1.1 1.2
Rvb Time Low Rt Mid Rt Crossover
2 2.0 2.1 2.2
Rvb Design Size Diffusion Shape
3 3.0 3.1 3.2
Pitch Detect Correct GldResp
4 4.0 4.1
Shift
Cents Semitones
5 5.0 5.1 5.2
Modulation *Mod:LFO *Mod:AR Env Mod:Env L
Patches Patch 0 Patch 1 Patch 2
3-54
FX Mix
Rvb In
Pitch
Chamber
Correct
Reverb
Rvb In
FX Mix
0.3 0.4 0.5
FX Mix *FX Hi/LoCut FX Width
1.3 1.4 1.5
Rt HC Pre Delay *Ref Lvl/Dly
2.3 2.4 2.5
Spread Spin Link
3.3 3.4 3.5
Tracking Low Pitch High Pitch
5.3 5.4 5.5
Mod:Env R *Mod:Latch *Mod:Sw 1
Patch 3 Patch 4 Patch 5
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.
FX FX FX FX
Width HiCut LoCut Adjust
0.6
*Lo/Hi Limit
1.6
*Eko Fbk/Dly
2.6
*Rvb Out/In
3.6 3.7
Tuning Splice
5.6
*Mod:Sw 2
Patch 6 Patch 7 Patch 8 Patch 9
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 key-
board, the audio is forced to the key-
board'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.)
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