ABC says DD 5.1, but it's not! (1 Viewer)

[Frank_S]

Watching ABC primetime movies over the weekend I noticed that I got NO center channel information. All dialogue came from my main speakers. My pre/pro said it was receving a 5.1 DD signal but it did'nt output what it should have. I know CBS transmits DD 2.0 which also has no center channel info but I can change that to DD pro-logic mode which gives me center channel audio. BTW, I'm using the optical connection on my Mits HD-400 STB. Did anyone else notice this over the weekend or for that matter anytime during their past HD programming?

 

[Dinesh]

the 5.1 channel you are receiving contains the stereo mix, apparently (i.e. the other 5 channels are deliberately encoded to not output any sound).
my guess is that the broadcast has always been received by you in stereo. You switched your mode to Pro Logic, which compares the left and right signals to generate a center channel and surround channel. Possibly the show was intentionally encoded in dolby surround, but it's just as likely that you were artificially creating a surround channel which was not necessarily intended.
In any event, when receiving a dolby digital signal, you no longer have the option to force the signal into a pro logic mode. or, more accurately, you can (I believe) tell your receiver to use the PCM signal, not the dolby digital signal, to decode the audio, then you can force it into surround as you are used to.
dinesh

 

[Frank_S]

Dinesh, you could be right. Last night I switched DD off on my Mits HD-400 HD receiver and listened for a few minutes in PCM pro-logic mode. The funny thing was that when I switched DD back on, I was receiving audio in all speakers, however, I really did'nt hear much difference in quality other than the fact that the 5.1 signal was louder. I'd like to find out if indeed they are transmitting a discrete 5.1 signal during some movies and NYPD Blue. I spoke with my local ABC affiliate today and he suggested I may have multi-path problems since I was also getting popping sounds intermittently as well.
After NYPD Blue was over my local news came on and the audio changes from 5.1DD to pro-logic. I heard no popping at all. I'll be installing a permanent antenna soon so we'll see what happens then.