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Technical Requirements for Dolby Surround
in Recording Studios
Using the Dolby SEU4 Encoder and SDU4 Decoder
Introduction
Dolby Surround is a format that enables the production and delivery of multi-dimensional
soundtracks for television, cable, consumer video, multimedia and other stereo media. Once
created, Dolby Surround soundtracks can be recorded, broadcast and reproduced the same as
any conventional stereo program, including compatible monaural playback. Consumers
equipped with Dolby Surround systems will experience the full measure of spatial dimension-
ality built into these programs, just as they do from thousands of Dolby encoded movies
currently available on home video media. This paper outlines the basic equipment necessary
for studios to produce soundtracks in Dolby Surround.
Surround Starts with Stereo
Many aspects of producing in Dolby Surround are the same as producing in stereo. The main
difference is that the mixing console must ideally have at least four buss outputs to feed a Dolby
Surround encoder, and some additional speakers and amplifiers are needed to monitor the
center and surround channels via a Dolby Surround decoder.
In most cases, the finished two-channel encoded soundtrack is all that will be recorded.
However, it is sometimes desirable to record the four-channel “stems” (encoder input signals)
onto separate tracks when further elements are to be added later, such as with music pre-mixes
for movie soundtracks.
Necessary Equipment
1.
Dolby Model SEU4 Surround Encoding Unit.
The SEU4 encodes four input signals (Left, Center, Right, Surround) into two output signals
(Lt, Rt).
2.
Dolby Model SDU4 Surround Decoding Unit.
The SDU4 decodes two input signals (Lt, Rt) into four output signals (L, C, R, S) using Dolby
Pro Logic Surround decoding technology. The unit also provides switchable stereo and
monaural monitoring modes for evaluating compatibility. A ganged master fader allows all
output channels to be varied together.
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