Lexicon DC-1 Supplementary Manual page 5

DC-1Theory
and Design
2
The DC-1 surround effects include a novel matrix technology which is
capable of extracting 5 or 7 channels from a two channel encoded original
in such a way that the left and right channels maintain full separation during
music. Although matrix decoders have been previously made with more
than 4 channels, they all reduce the separation in the rear channels when
decorrelated material such as music is being decoded. The matrix effects in
the DC-1 maintain full separation and envelopment during the music
sections of films, and for music CD recordings.
The Ambience (Nightclub and Concert Hall) and Reverberation (Church
and Cathedral) algorithms transform the listening room into a new acoustic
space, letting you choose an environment which matches your music or
your mood. Unlike most ambience processors, the DC-1 provides full stereo
processing, preserving the critical SI information in the recording and
expanding upon it. The Ambience algorithm generates the side and rear
reflection patterns of idealized rooms and concert halls. The larger spaces
add the true depth and realism of a concert hall to classical and popular
music, while the smaller spaces are ideal for jazz and rock. The Reverbera-
tion algorithm is similar, but places more emphasis on rich, dense reverber-
ant decay than on early reflections. It is especially good for simulating large,
highly reverberant spaces such as churches, stadiums, and cathedrals.
When a listener is in the correct spot the Panorama effect provides an almost
ideal re-creation of the original recording space. It works by using digital
signal processing to cancel the crosstalk between the listener's ears, effec-
tively spreading the sound from the two front loudspeakers in a wide arc in
front of the listener. With the optional addition of rear speakers, Panorama
can be startling in its realism.
The requirements for processing sound for home theater are somewhat
different than those for music and the DC-1 programs available using the
new Surround algorithm meet all of these requirements. Lexicon invented
the technology that permits the most accurate reproduction of film sound
in the same system that is used for music listening, and the software-based
DC-1 is optimized for each of these unique tasks. The Music Surround effect
is specifically designed to optimally play conventional stereo music
through any system which includes side or side-located rear speakers.
Additionally, the DC-1 is able to perform automatic analysis and error
correction to compensate for problems in the source material.
The new 5 channel and 7 channel surround decoding allows the stereo
music in soundtracks to be reproduced with a full stereo spread, unencum-
bered by the relatively narrow separation of the front speakers. Left-to-
surround and right-to-surround pans are also enhanced. Instead of sound
jumping from a front channel to both surrounds, the left and right side
speakers can function independently to facilitate smooth and fluid pans.
Sounds directed to hard left and hard right (the main left and right speakers)
will not appear in the side surrounds.
Lexicon