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7.1 system... no sound from back speakers. Please help!

post #1 of 11
Thread Starter 
Hi all. First post here. I finally took the jump to Blu-ray and a 7.1 sound system. I've recently purchased the Onkyo HT-S6200 HTIB and the Sony BDP-N460 blu ray player. I have it all connected to a Samsung LN52B750 TV. I ran through the automatic (Audyssey) setup and all the speakers work great.

However... whenever I play a blu-ray disc, no sound comes out of the back speakers. The center, front left\
ight and side left\
ight speakers work great. Am I correct in thinking that I MUST have a 7.1 blu-ray disc that has 7.1 sound on it to hear anything from the rear speakers? Most of the newer blu-rays I've seen on netflix only say 5.1 Dolby TrueHD and 5.1 DTS-HD.

The HT-S6200 receiver has a "Dolby PLIIx Movie" and "Dolby Digital EX" settings that put sound out of the back speakers but from what I understand, it's just putting the sound from the side speakers out the back. Should I even concern myself with these settings?

I'm kind of at the end of my rope with all this. It's been tough getting everything up since I'm not up to speed on all this stuff. I'm starting to ask myself why I bought a 7.1 system if it is only going to output 5.1 sound! Any help would be appreciated!!!!
post #2 of 11
most blu rays are 5.1. you can on some avr's and prepros apply post processing to get 7 channels as you adroitley alluded to but if there is only 5.1 on the disk that's all you should expect to come out without utilizing post processing such as pIIx/thx...etc--some of these involve using matrixed versions (wikipedia dolby pro logic for a good explanation) to send to the back 2 speakers so the signal is usually not exactly the same. hope that helps!
post #3 of 11
As the previous poster said, there are very few blu-ray movies with 7.1 sound. I put in a 7.1 system because I thought it would be more economical that adding it latter. Hopefully there will be more movies with 7.1 sound in the future. If you like westerns or just want to prove your system get the movie 3:10 to Yuma which has 7.1

Ray
post #4 of 11
Thread Starter 
I see. Thanks for the confirmation. I did a search on 7.1 movies and I saw 3:10 to Yuma... only bad thing about that is that we just watched it about a week ago (before the new system was hooked up!). Haha...

Another question... so do some people here use the post processing effects to put sound out of the back speakers? Or is it frowned upon?
Thanks again!
post #5 of 11
Quote:
Originally Posted by bwhited View Post

The HT-S6200 receiver has a "Dolby PLIIx Movie" and "Dolby Digital EX" settings that put sound out of the back speakers but from what I understand, it's just putting the sound from the side speakers out the back.

The sound from the side speakers is not duplicated to the rear speakers. Instead, sounds that normally would have phantom imaged behind you are cancelled from the sides and sent to the rear speakers.

EX is older technology and sends the same surround-back info to both rear speakers, running them as dual-mono. PLIIx extracts stereo information for the rear speakers, so each gets independent signals.

So if there is a sound that travels from the left surround channel to the right surround channel, it will pass through each of the surround speakers (one by one) for a smooth pan from your left side all the way to your right side. Couldn't do that if the rears just duplicated the sides.
post #6 of 11
Quote:
Originally Posted by bwhited View Post

I see. Thanks for the confirmation. I did a search on 7.1 movies and I saw 3:10 to Yuma... only bad thing about that is that we just watched it about a week ago (before the new system was hooked up!). Haha...

According to the blu-ray stats site, they list 132 titles with 7.1 sound. I would recommend cross referencing to IMDB & AVSForum for confirmation though.

Mike
post #7 of 11
Quote:
Originally Posted by raylock View Post

I put in a 7.1 system because I thought it would be more economical that adding it latter.

Quote:
Originally Posted by sdurani View Post

The sound from the side speakers is not duplicated to the rear speakers. Instead, sounds that normally would have phantom imaged behind you are cancelled from the sides and sent to the rear speakers.

EX is older technology and sends the same surround-back info to both rear speakers, running them as dual-mono. PLIIx extracts stereo information for the rear speakers, so each gets independent signals.

So if there is a sound that travels from the left surround channel to the right surround channel, it will pass through each of the surround speakers (one by one) for a smooth pan from your left side all the way to your right side. Couldn't do that if the rears just duplicated the sides.

As sanjay points out, though, there is no reason at all that you can't already be getting plenty of worthwhile enjoyment from a 7.1-ready setup even without truly discrete 7.1 material.
post #8 of 11
Thread Starter 
Ok, I think I am understanding a little more... one more question though:

I tried watching a blu-ray last night and something strange happened. I have everything hooked up via hdmi 1.3a. When I played the movie, the Onkyo ht-s6200 said "PCM Multichannel HDMI" on the display instead of Dolby Digital 5.1 or DTS 5.1 (I made sure the blu-ray was set to Dolby Digital 1.5 on the onscreen menu).

What is PCM Multichannel? Is it better than DTS or Dolby? It was a lot quieter than DTS or Dolby. I had to turn my receiver up to 60 (max is 79) to get to the desired level. I tried a standard DVD and it said Dolby Digital 5.1 on the receiver. I only had to turn the standard DVD up to about 48 or so to get to the desired level. Why is this? No matter what settings I played with (on the receiver or the Sony BD player) I couldn't take it off of PCM Multichannel and make it say DTS/Dolby Digital for the blu-ray movies.

Thank you so much for the answers.... I have a lot to learn I guess...
post #9 of 11
Quote:
Originally Posted by bwhited View Post

What is PCM Multichannel?

Without going into a lot of detail, MPCM is what your player will pass to your receiver when you decode at the player as opposed to decoding at the receiver. You can do some reading up here and elsewhere regarding decoding at the player vs. decoding at your receiver.
post #10 of 11
Do yourself a favor and turn and keep on your Dolby Pro Logic IIx Cinema listening mode for all your 5.1 tracks. It's really fantastic and faithful to the soundtrack, matrixing it to 7.1.
post #11 of 11
Quote:
Originally Posted by sivadselim View Post

Without going into a lot of detail, MPCM is what your player will pass to your receiver when you decode at the player as opposed to decoding at the receiver. You can do some reading up here and elsewhere regarding decoding at the player vs. decoding at your receiver.

Can you recommend where we would read up on this? I'm interested in this, as I bought an older model receiver that does not extract the high definition, 7.1 channels, so therefore I might buy a Bluray player that does and run the outputs into the receiver.
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