Specifications

5.1-Channel Production Guidelines Production Techniques
5-9
version while retaining flexibility in the exact proportions of each channel
represented in the final stereo mix.
Created by Decoder
This option does not create a separate mix. In this case, the decoder derives a stereo
downmix based on preset formulas. When applicable, consumer decoders will apply
dynamic range reduction during the downmix process to prevent overload. All
downmix and dynamic range control options can be previewed in the production
studio. A range of adjustments is possible and the resultant effect can be checked in
advance. For additional information on the downmix process in the decoder, please
refer to the Dolby Digital Professional Encoding Manual.
5.3.6 Upmixing
Upmixing describes the process where additional new channels of audio information
are created from an original soundtrack, for example making a 5.1-channel version
from a stereo master.
The term “5.1” has strong appeal to many people. Consumers and professionals alike
can sometimes be drawn by the idea that a soundtrack available in 5.1 is somehow
better than a stereo or mono soundtrack. However, there are many instances where
this may not be true. For example, an old black-and-white movie may sound
incongruous with a 5.1 soundtrack, and mono may be the better format in this case.
Conversely, there are instances where there is a legitimate need for a multichannel