Lexicon CP-1 PLUS V2.0 Owner's Manual page 57

Theory
and
Design
Page 52
In Music Logic (as in the Concert Halls mode), the front left and right
outputs are attenuated by the volume and balance controls, but are other-
wise unaltered by the processor. This absence of main front steering is ideal
for playing stereo music, where the original stereo signals are reproduced
from the front speakers with absolutely no alterations. Music Logic really
shines on this material — the side and rear speakers contribute a tremen-
dous amount of spatial impression.
For film use the lack of steering of the main speakers is noticeable on dialog,
and any of the normal film surround modes may give better results. If the
system has no center loudspeaker main steering is not needed, and Music
Logic may well be preferred over the other modes.
Stereo Logic
The Stereo Logic program is primarily designed for the playback of music
through film-sound systems. Its basic structure is similar to Pro Logic but
it contains more variable parameters. In the Preset version of Stereo Logic
these parameters are set for music but they can be changed to produce a
versatile program for film sound as well.
The range of the Rear Delay parameter is 0-32 ms, as opposed to 16-32 ms
in Pro Logic, for use with music programs in which you may want to hear
the front and rear outputs of the program simultaneously.
Music does not necessarily contain a crucial, centrally located element
analogous to the dialog in films. So the Preset version of Stereo Logic has
no automatic adjustment for interchannel time delay and balance (that is,
the Auto Azimuth/Balance parameter is off). The Front Effect parameter,
which controls the steering among the front three channels, is preset half
way up, meaning that centrally located sounds are diminished by 6 dB in the
side speakers and vice-versa. The setting for Dolby Stereo films is 16 (up all
the way).
The Rear Effect parameter controls the steering of effects, music and
ambient sounds to the rear speakers. Its preset value is determined by the
speaker configuration specified by the user. (See page 15.) The preset value
is zero if there are no rear speakers in your system and 8 (of a possible 16)
when there are rear speakers. When the Rear Effect is set to zero all rear
sounds appear in the front left and right speakers (and the side left and right
speakers, if present).
The Rear Noise Chip parameter is preset to OFF, meaning that the high-
frequency sound in the rear channels is set solely by the Rear Rolloff
parameter. (The Rear Noise Chip should be ON for Dolby Surround
programs.) Rear Rolloff is preset to 14.1 kHz, its highest constant value. An
Automatic mode expands to accommodate signals steered to the rear, then
shuts down to 7 kHz for lower percussion leakage when there are no signals
there. This is a useful feature for films.
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