Variable Delay; Pitch Shifting - Lexicon Prime Time 93 Owner's Manual

The vocal doubling from the previous section relies upon a constant time
difference to create an illusion that there are really two voices. But in
reality, two voices will have varying time differences between them. By
varying the time delay on M.93, which can be done automatically with the
VCO, vocal doubling seems more realistic.
A variety of other special effects can be generated by varying the time
delay either manually or automatically. Changes in pitch can be accomplish-
ed by rapidly changing the delay, so called "doppler" pitch shifting. If
this is done at the appropriate speed and degree, then a vibrato can be
simulated. Flanging is created by varying the time difference between the
source and the delayed signal or between two delayed signals which are mixed
at equal levels. The VCO is also applicable to other effects which will
be discussed in coming sections.
VARIABLE DELAY
Using a delay set-up from the previous section, turn the DELAY ADJUST control
away from the "(cal)" position (make sure DEPTH is CCW). The UNCAL indica-
tor will light indicating that the delay is now determined by the VCO and
not by a crystal frequency standard. Varying DELAY ADJUST will change both
delays A and B by a factor corresponding to the position of the control from
lX to .5X of the indicated delay times. Thus, delay times which are not av-
ailable from the DELAY SELECT controls can be gotten using DELAY ADJUST.
PITCH SHIFTING
DELAY ADJUST can also be used to create some of the special effects referred
to earlier. Listening to the MASTER OUTPUT with OUTPUT MIX controls IN and
B down (so. that only a single delay output is heard), vary the DELAY ADJUST
control to create "doppler"pitch changes in the output. Turning the con-
trol clockwise increases the pitch; turning the control counterclockwise
decreases the pitch. Greater pitch changes up to a maximum of one octave
can be achieved by turning DELAY ADJUST more rapidly or by selecting a
longer delay time. Create a vibrato by rapidly turning DELAY ADJUST back
and forth, selecting a delay time for an optimum effect.
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