Lexicon CP-1 PLUS V2.0 Owner's Manual page 59

Theory
and
Design
Page 54
The Mono Logic program electronically identifies certain properties of film
speech and removes it from the stereo synthesis. This allows music and
effects in the dialog to be spread out while leaving the dialog centered. The
remaining music and effects are directed to the input of a room simulation
program that creates a space the size of a large room or small theater. The
room simulator has outputs for left, right, side and rear surround speakers.
The monaural input sound from the film is unchanged in the center speaker,
so that all the dialog and music that the director expected to come from the
screen still does, with no modification or reverb. Partly because of the
acoustical character of the room synthesizer, the result is often so successful
that switching from a monaural input with Mono Logic to a stereo input
with Pro Logic may make a surprisingly small difference.
The most critical adjustment in Mono Logic is the Effect Level. Ideally the
film's music and effects should appear to come from the front but with the
added sense of a large space surrounding you. The side and rear speakers
should not be individually audible.
TV Matrix
Television sound playback presents a challenge simply because of the wide
variety of recording and processing techniques used in program produc-
tion and transmission. Programs and commercials are recorded in mono,
stereo, and surround sound, then subjected to compressors, erratic stereo
synthesizers, sleepy production interns, and other electronic tortures. Often
all of this can be experienced on one channel within five minutes.
The TV Matrix mode makes use of directional steering to enhance dialog in
the center channel and remove it from the left and right channels, while
maintaining as much stereo separation as possible. In addition, it contains
several interesting variable parameters. In the Preset version of TV Matrix
these parameters are set for pleasing results with a wide variety of program-
ming, but they can be changed to produce a versatile mode for film sound
— and some music as well.
The Front Effect parameter, which controls the steering among the front
three channels, is preset at 12dB, causing centrally located sounds to be
diminished by 3dB in the side speakers and vice-versa.
The rear noise reduction parameter (Rear Dolby B) is preset to ON, meaning
that the high-frequency sound in the rear channels is being decoded by the
Dolby B circuit. This control may be turned off for non-surround-encoded
material.
The Side Speaker parameter can be used to connect the side speakers in
parallel with the front speakers. The resulting wide frontal image is very
effective on a wide variety of films and music.
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