Lexicon 300L - REV Owner's Manual page 88

Stereo Pitch Shift Page One
MOD selects stereo or mono mode. In stereo the two channels are linked, pitch
shifting by the same amount and splicing at the same time.
SNC is only active in Stereo mode. This control forces an exact sync of the two
channels when the control is turned from Off to On. When SNC is On, there is
an automatic re-syncing any time the two channels differ in phase by about 10
samples. This can occur if PCH, LDL, or RDL is changed. Re-syncing can cause
a small click in the output. If the pitch shifter is being used to manually pitch-
correct classical music, it may be better to set SNC to Off. There is an automatic
sync tracking feature which will keep the two channels locked to within 2
samples. If precise synchronization is desired, the LDL and RDL controls should
be set to the same value, SNC should be set from On, and then the pitch should
not be changed. The two channels will remain precisely synchronized, even
though both are continually changing the splice length in response to the
incoming pitches.
The leftmost PCH control adjusts the pitch interval of both channels in stereo
mode, and the left channel in mono mode. The second PCH control is only active
in mono mode, where it adjusts the right channel. The exact tuning can be altered
by the fine pitch control, and the exact pitch shift in intervals and cents is
displayed. The fine control must be set to the exact middle of its range if perfect
pitch intervals are to be obtained.
In the long display, Fine Pitch is shown by the number of cents added to, or
subtracted from, the semitone intervals. Remember that Pitch Interval will
produce exact intervals only if Fine Pitch is centered.
The leftmost FIN control acts on both channels together in stereo mode, and the
left channel in mono mode. It adjusts pitch continuously over a range of a few
hundred cents, and is additive to the PCH controls. If PCH is set to the middle
of its range the leftmost FIN control can be used to set very small values of pitch
shift, producing a chorusing effect.
The second FIN control is only active in mono mode, where it adjusts the right
channel.
Stereo Pitch Shift Page Two
LDL adjusts the length of a delay line in series with the left input. The range is
zero to 510ms in 2ms steps.It also affects the delay of any feedback which is
applied. In stereo mode the two delays must be set to the same value, or the
signals will not be in phase. Optimal pitch shift occurs when LDL is about 40ms.
RDL is the same as LDL, except that it affects the right channel.
The Algorithms and their Parameters
MOD (Mode)
SNC (Synchronization)
PCH (Pitch Interval)
FIN (Fine Pitch)
LDL, RDL (Left and Right
Delays)
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