Accommodating stereo playback – Apple Compressor 2 User Manual
Page 107
Chapter 7
Creating Dolby Digital Professional Output Files
107
Because LFE is separate from other channels, its ability to blend with higher
frequencies can be affected by filters used to generate the LFE signal. To ensure a
cohesive audio signal, keep the entire signal together in the main channel or channels.
Avoid creating an LFE channel for material originally produced without one. Dolby
Digital Professional’s five main channels are all full-range, and the LFE channel does not
increase the frequency response. Dolby Digital Professional decoders offer bass
management, directing low frequencies to a subwoofer or other suitable speakers. An
LFE track may interfere with bass management.
Accommodating Stereo Playback
Even with the popularity of 5.1 systems, you should always address stereo reproduction.
There are three basic ways to do this:
 Prepare a new stereo mix from the original multitrack elements (using conventional
stereo-mixing sessions).
 Prepare a studio-adjusted downmix from the multichannel mix. This method takes
advantage of the work that has gone into mixing the 5.1 version. It retains flexibility
in the exact proportions of each channel represented in the final stereo mix.
 Let the decoder derive a stereo downmix, based on preset formulas in the decoder.
Downmix options and dynamic range control effects can be previewed and adjusted
in the production studio, and a range of adjustments are possible.
Always check the mix on an inexpensive surround system to evaluate how well it
sounds on modest playback systems.
Note: For more information about Dolby Digital Professional, see “Frequently Asked
Questions about Dolby Digital Professional,” available at the Dolby Laboratories Inc.
website: