Lexicon LEXICON480LV4 Owner's Manual page 53

Lexicon 480L Owner's Manual
Page One
SPN
Spin
Page Two
MON MON
Input Blend Input Blend Feedback Level
Page Three
HPL
High Pass L
About the Effects Program
The effects in the 480L are based on randomly varying
time delays. Within this general class a great variety of
sounds are possible. Of greatest interest are the natu-
ral acoustical effects, such as the effect of a forest on
sound, a drum cage, or reflections from audiences,
walls, and rooms. Most of these natural effects are
quite complex, and are difficult or impossible to obtain
using a delay line with fixed taps. The effects of slightly
moving sources, or several musicians, cannot be ach–
ieved with fixed time delays and only one input. Simple
clusters of delays (which produce an interesting sound
when first heard) become annoying when the timbre
they create applies in exactly the same way to every
sound run through the box.
In the 480L, the delay pattern and the resulting timbre
is never constant long enough to become boring.
Making the taps randomly vary in time solves many of
these problems, and allows the creation of more inter-
esting sounds.
Perhaps the oldest time-varing effect is simple chor-
using, where a single input is delayed with a number of
taps, and the time delay of each tap randomly varies in
time. Such a program makes a chorus out of a single
voice. In the 480L, chorusing uses up to 40 voices, 20
on each input channel.
The unique way in which the 40-voice effects algorithm
processes these voices provides a chorus that does not
change pitch.This is extremely useful on material such
as grand piano, where detuning from standard chorus-
ing yields unacceptable results.
Delay times can be combined in phase, or out-of-
phase, to change the timbre of the overall effect.
4-2
SLP LNG
Slope Length
FBL FBD
Feedback Delay
SGN
HPR
Signs
High Pass R
NUM
WAN
Number
Wander
DIF
IND
Diffusion
Input Delay
For many effects 40 voices is not enough--we might
want much more than that to simulate the irregular
surfaces of a drum cage, many trees in a forest, or
many cars in a parking lot. To accomodate this, we
have added a diffusion control, so that each of the 40
voices may be expanded into a dense cluster of
reflections.
Some reflective surfaces, such as people or music
stands, reflect high frequencies primarily. To allow
emulation of these, we have added a high-pass filter
with 12dB/octave slopes.
Natural effects are not the only ones possible. The
time-varing taps may be adjusted so they lie on top of
each other, creating phasing and flanging which is
quite interesting and unique. This phasing can be
delayed with the PREDELAY, and then made into
echoes with FEEDBACK, creating ghostly sounds
which bounce and repeat.
In addition, by using the INPUT DELAY control, the
effect can be made to precede the sound which
created it; thus a high frequency brilliant edge can be
added to a cymbal crash before the crash is struck, and
the amount of the edge, and its tone quality, will be
different every strike.
All these sounds are made available through a few
simple controls.
PDL
Predelay
MIX
Wet/Dry Mix