Lexicon CP-1 Theory Of Operation page 21

Multi-Channel Music & Cinema Systems
Theory and Design
TV Viewing
18
Our own LOGIC 7 effect takes decoding further with the introduction of
true seven channel decoding using a stereo surround process. Steered
signals are panned to the front, side and rear speakers so that surround
information follows the visual movement on-screen. Ambient surround
information, such as stereo music in the soundtrack, is reproduced at full
bandwidth and in stereo in the rear channels. Sound effects which pan to the
left or right of the listener are reproduced with full realism.
DOLBY DIGITAL and DTS effects decode six discrete channels of digital
information from encoded soundtracks. Improvements to film sound re-
production include improved dynamic range, superior channel separation,
a dedicated subwoofer channel, and discrete sound effects. For each format
we include THX enhancements as well as our own music enhancements.
The 5.1 2-CHANNEL effects mix 5.1 information down for two-channel
playback. Soundtracks can be recorded onto two-channel formats for later
playback through a surround effect such as Logic 7, or they can be played
back through left and right front speakers.
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 effect 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.
Lexicon