2009-11-13, 01:24 PM
A friend noticed that while watching some HD channels it will not be coming through on his receiver in 5.1 even though it says 5.1 in the guide. He has shown me where a program will be coming through on right front and rear only and no other channels have anything coming through then the next program comes through with all 5 channels working. This has caused him to be forced to watch some of his programs using the TV speaker. Anyone else notice unusual 5.1 sound issues lately?
I've been told most amps will compensate automatically and mix the feeds faking a surround sound effect but this does not work on his amp (a little older model)
This is improperly encoded DD5.1 audio and is discussed as items 1 & 2 in the following FAQ. Workarounds and other information on similar issues are also discussed there:
CBC and sometimes PBS do this a fair bit because they don't wish to switch back and forth between DD5.1 and DD2.0 because that causes issues with their (older) equipment, therefore rather than sending out DD2.0 for DD2.0 programming, they send out DD5.1 all the time but only two-channels for those programmes that are not true DD5.1.
The right-front/rear issue has happened very occasionally, but he should also check his speaker connections with the test tones on his AVR to ensure they're connected properly. There is really not much that can be done with improperly encoded DD5.1, although sometimes you can use the analogue audio connection to the amp and process it using Dolby Pro Logic.
The analogue audio connection will work for improperly encoded audio, but will not bring back missing dialogue - for that I recommend using closed captioning.
Guides are notoriously incorrect for information such as HD or DD5.1.