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5.1 -> 7.1

1696 Views 9 Replies 7 Participants Last post by  chavel
Can somebody explain to us the various ways there are to convert 5.1 recordings to 7.1 for playback on a 7.1 system. That is, what formats can and what formats cannot be transformed into 7.1 using a modern HTR.

For instance, I can get DD 5.1 SPDIF to convert to 7.1 with PLIIx with the Yamaha HTR 6090 but I have had zero luck in getting 5.1 MPCM 176 kHz SACDs over HDMI from a PS3 to convert using PLIIx or any of the canned sound field programs.

The manual makes it sound like there shouldn't be a problem in getting the surround backs to fire with any and all 5.1 input.
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Prologic IIx is pretty much the only way to get 7.1 sound out of a 5.1 signal on most receivers. Some receivers will do DTS Neo:6 as well, but that only gives 6.1 sound (both back speakers would have the same signal in a 7.1 situation). [What about Logic7?]

Depending on your receiver, you may or may not be able to apply PLIIx to all 5.1 sources. For example, I cannot use (on my Pioneer VSX-816) PLIIx for multi-channel analog sources, DTS 96/24 or PCM 96 sources. More expensive (with more powerful CPUs) may have better luck in these situations.
I just got off the phone with Yamaha who said that that the 6090 should be able to playback any 5.1 source in 7.1. He placed the blame on the PS3's handshake with the reciever since DD 5.1 SPDIF was being processed with PLIIx to 7.1 without any problems.
Some may not 'approve' of the following method, but there is another possible option. If you are running analog out from a DVD player into a receiver that has 7.1 inputs, then you can run the surround left and right into Y-splitters and basically duplicate the signal to both surround left and surround BACK left and ditto for the right. Granted this may skew your soundfield a bit and isn't a good solution is every room, but if your room is large, or at least long, I have found that it can provide a larger soundstage. Just my .02, so take it or leave it.


Edit: Ok, so I just re-read your post and realized you're trying to run through the PS3, so basically...nevermind!
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Is it such a good idea to apply processing to convert 5.0/5.1 to 7.1 in music? It rather goes against the original intention of the recording.

Originally Posted by Kilian.ca /forum/post/0

Is it such a good idea to apply processing to convert 5.0/5.1 to 7.1 in music? It rather goes against the original intention of the recording.

Depends on what you see the "original intention" as being. Was their goal specifically to have you hear all the surround information played back through only 2 speakers? Or did they want the surround field to wrap around you in a seamless arc? If it's the former, then you shouldn't play back 5.1-channel material on anything but a 5.1-speaker set-up. If it's the latter, then 2 surround speakers are going to have difficulty providing envelopment at your sides and behind you simultaneously.

On a properly set up a 5.1-speaker system, sounds that are the same in both surround channels should appear inbetween the 2 surround speakers; usually phantom imaging behind you. But to hear this rear directionality, you have to be sitting right between your surround speakers. If you stretch out on the couch or for whatever reason end up off-centre, that phantom rear image will collapse to the nearest surround speaker.

If you extract those sounds and send them to another pair of surrounds placed behind you, then they will always come from the intended direction, no matter where you're sitting/relaxing when listening to music. Is the fact that those sounds are now being reproduced from a hard source instead of being heard as a phantom image going against the original intention of the recording? If they specifically wanted you to hear those sounds as phantom images, then it is going against their intent. But if they simply wanted you to hear those sounds behind you, then it's not. Who do you ask for confirmation?

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I have actually gone one step further to 8.1!

The Meridian 861 processor I use has a number of surround algorithms that will 'create' side channel signals from 5.1. I then use an older ADA 6.1 matrixer to extract a rear center channel from the 2 rear channels. REALLY WORKS WELL!

Now if I could only figure out how to generate an overhead channel!

Originally Posted by chavel /forum/post/0

I just got off the phone with Yamaha who said that that the 6090 should be able to playback any 5.1 source in 7.1.

Of course, yamaha's are magic. Phantom speakers rule...sorry had to it makes me giggle.
It's still no dice on getting anything 5.1 out of the PS3 that will allow DPLIIx to stick with the Yamaha 6090. I've checked and unchecked every box in the hdmi sound menu on the PS3 and the only way I can get DPLIIx processing is by unchecking all of the 5.1 an d 7.1 boxes and sending only 2 channels to the 6090. This includes bit stream DD from DVD's over HDMI. The Oppo 971H allows for DPLIIx with 5.1 over SPDIF.

I've asked if anyone is gettting DPLIIx processing on hdmi 5.1 from a PS3 with any brand HTR on a couple of other threads without an answer. Maybe I'll get one here?
Might as well close this thread out with the reason why I couldn't get PLIIx to work on the 176.4 kHz MPCM signal from SACD on the PS3. It turns out that the Yamaha 6090 and I'm sure a lot of other AVRs max out at 96 kHz for signal processing. In order to get PLIIx to work all you have to do is go into the PS3 HDMI sound menu and uncheck the 176.4 kHz box leaving the 44.1 and 88.2 boxes checked. This way the reciever gets 88.2 kHz and and you're firing on all 8.

I guess I didn't quite uncheck and check every box in the sound menu and thanks to joealtus in the BluRay player forum for telling me what the problem was.
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