Primer
Crestron
Surround Sound
the appropriate channel while canceling other channels. The amount of
enhancement applied is relative to the level of dominance.
Dolby Pro Logic II
Pro Logic II includes bass management, allowing bass to be reproduced
from the main speakers, or an LFE (Low frequency effects) output.
Pro Logic II uses directional enhancement, and a feedback loop allows
the anti-phase signals to more closely match unwanted crosstalk
signals. Control of the spatial dimensionality and front sound field are
also provided.
Dolby Digital
Storage and playback of audio signals in a digital format has a lot of
advantages over analog. Low-cost digital signal processing (DSP) has
revolutionized the audio/video industry. The availability of complex
processing coupled with increases in storage density has opened up
new possibilities in audio/video coding and playback. As its name
implies, Dolby Digital, introduced in 1997, takes advantage of DSP. It
uses a digital processing method, which exploits the limits of human
hearing.
Playback of Dolby Digital is similar to that of Dolby Surround, but the
technologies are very different. Dolby Surround is primarily on analog
storage media, but Dolby Digital is a digital-only coding system.
Dolby Digital Surround EX
Dolby Digital Surround EX provides a third surround channel on Dolby
Digital movie soundtracks. The third surround channel can be decoded
at the cinema or home viewer for playback over surround speakers
located behind the seating area. Surround speakers to the sides
reproduce the left and right surround channels. The back surround
channel is matrix-encoded onto the left and right surround channels of a
conventional 5.1 mix, permitting conventional 5.1 playback.
A/V receivers are available with either Dolby Digital EX or THX
Surround EX decoding which derives the extra surround channel for
playback in 6.1 (three surround speakers) or 7.1 (four surround
speakers) configurations. The additional rear speakers are matrixed and
not discrete in nature.
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Surround Sound
Primer – DOC. 6122
