Lexicon CP-1 PLUS V2.0 Owner's Manual page 52

CP-1 Digital Audio Environment Processor
with true binaural recordings, which have very little out-of-phase low
frequency energy. A few compatible binaural recordings are becoming
available, in which the low frequency width has been increased to match the
requirements of loudspeaker playback. These recordings may sound best
when played with the Normal setting.
Panorama is capable of simulating side loudspeakers effectively, but cannot
mimic sound sources to the rear of the listener. So we have added a simple
delayed Left minus Right signal which can be sent to rear loudspeakers.
The delay is adjustable, as is the treble rolloff.
For a listener in the ideal position, Panorama, with one or two rear speakers,
gives a nearly ideal re-creation of the original recording area.
Panorama is also used as an element in the Concert Hall mode, where it can
synthesize side loudspeakers which are not present in the installation. In
this mode the stereo inputs to the CP-1 are fed directly to the front
loudspeakers, with the digital outputs of the CP-1 mixed in according to the
setting of the Effect Level control. The Concert Hall side outputs are sent
through Panorama before being mixed into the front loudspeakers, so the
added sound spreads beyond them and does not interfere with the original
material. When side speakers are present, the Panorama Effect parameter is
automatically turned down and no mixing occurs into the front speakers.
While the Panorama effect recreates the space that already exists in the
recording, the Ambience effect actually generates the side and rear reflec-
tion patterns of a number of ideal concert halls. The reflections were
determined by computer ray-tracing using architectural data, augmented
by Lexicon's 15 years of experience with digital concert-hall simulation.
The Ambience simulation is done in stereo. Instead of feeding combined left
and right channels to the processor, the CP-1 has two input points corre-
sponding to instruments placed on the left or right side of the stage. From
these the computer calculates the loudness and delay of the reflections for
the side and rear loudspeakers.
Ambience generates primarily the strong reflections which appear early in
the reverberation process (in the first few hundred milliseconds). Although
some reverberant decay can be added with the Liveness parameter, the
early reflections constitute the primary audible effect, giving you the
impression of the hall surrounding you while the music is playing. As in
actual concert halls, the most important contribution to spatial realism will
be the sound that comes from the sides.
Theory
Design
Speaker alignment is important. A
6" difference in the distance to the
rear wall can greatly change the ef-
fective area, unless compensated for
by the LISTENER POS parameter.
The Ambience
Effect
(Small Club
and Concert
Hall Presets)
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