Installation manual

UEX/650 Upgrade Kit Installation
9
About Dolby Digital Surround EX
Dolby Digital Surround EX adds a third surround channel to digital film sound, a
concept first envisioned by sound designers at Lucasfilm’s Skywalker Sound post-
production facility. Jointly developed by Dolby Laboratories and Lucasfilm THX
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Dolby Digital Surround EX gives sound mixers a new level of creative freedom.
Dolby Digital Surround EX is fully compatible with all current 5.1 digital sound
formats and theatre systems. Prints that use it play normally with current systems, and
provide the extra surround channel when played using a CP650 cinema processor
equipped with the Cat. No. 794 board, or earlier Dolby cinema processors equipped
with the Dolby model SA10 adapter.
It has long been known that a center screen channel is necessary to ensure the precise
localization of front sounds for all viewers, including those seated off to the sides.
Dolby Digital Surround EX brings similar benefits to the surround sound field. With
Surround EX, a back surround channel is reproduced by the speaker array at the back
of the theatre, while left and right surround is reproduced by the side arrays. This
means that sounds can now be positioned behind the audience, opening the door to
exciting new effects, such as true 360° pans.
The back surround channel also makes front-to-back and back-to-front transitions
more realistic. Flyovers really seem to pass overhead, rather than down the sides of
the theatre. Even ambient sound reproduction is improved, being less affected by the
width of the theatre. Equally important, the new back surround channel assures that
even viewers seated close to the left or right of the theatre experience the total
surround ambience intended by the filmmaker.
The UEX650 kit upgrades the CP650D 5.1-channel digital cinema sound processor to
three surround channels that can play digital prints prepared with the Dolby Digital
Surround EX process. The installation requires wiring the surround speakers into left,
back (split into two groups), and right. Two power amplifier channels are required
for powering the two groups of back surround channel speakers. The figures below
show the surround signal distribution for conventional 5.1-channel surround and for
Dolby Digital Surround EX format.