# 5.1 vs 7.1 surround Newbie question



## Guest (Jul 9, 2007)

My apologies, this is probably pretty basic, but I'm new to all of this. I'm looking at buying the Onkyo HT-S990THX 7.1 Home Theater System, from the reviews I've read and for the money it seems to suit my needs. That's neither here, nor there. I was looking at the pdf I downloaded of the manual for the receiver to prepare my shopping list for cabling that I might need to buy and I see that it has inputs for the audio for 7.1 (stereo front, center, sides, rears). It said "If your DVD player has a 5.1-channel analog audio output, don’t connect anything to the AV receiver’s SURR BACK L/R jacks." As my DVD player is extremely old, I thought I might purchase a newer one in the interim until the current Blu-Ray vs. whatever format war is decided. Remember the betamax?! So I looked on the net searching for a DVD player with 7.1 audio outs on it. I didn't find any. Not on the most expensive one I found did I see any. 
My question is are there any? (and I don't want to pay a whole lot for a DVD player that will be old news in another year or two!)
And if not, why is there 7.1 receivers and nothing to utilize them with? 
If the only option available (at this time) is 5.1 then will any sound be output to the other two speakers at all? 
Is it a waste of time mounting them? 
Would I be better served to make them speakers for another room? 
Is there some sort of decoder unit that goes in between the DVD player and the receiver that gives another split for the other pair of speakers?

OK, I realize that's several questions in one post, but I do appreciate any advice/help that anyone can give me.

Sincerely,

Mike W.


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## Otto (May 18, 2006)

Hi Mike, and welcome to the Shack!

There really isn't material recorded/mastered in 7.1 (actually, there might be a thing for 6.1 in DTS, but that doesn't matter). The extra two channels are generally "derived" from the 5.1 signal when processed by the receiver. Most of us use a digital connection from DVD player to receiver. In that case, everything will be taken care of for you, as the receiver is doing all the processing. 

I have never used the analog 5.1 outputs on my DVD player. The only way I would do that is if I were using a BluRay/HD-DVD player with a receiver/pre/pro that did not process the audio via HDMI. 

I'm not sure why the receiver would be engineered that way necessarily, though. Actually, I'm not sure if it means ABSOLUTELY, DO NOT connect anything to the Surr Back L/R jacks (these are speaker outputs, I'm presuming), or if it meant to say that "you will not get anything out of the Surr Back L/R channels because the input you are providing is only a 5.1 set." If you were using a DVD player with 5.1 outs to the receiver and another DVD player with a digital connection (just for example) and you had 7.1 speakers, you could indeed get signals from the digitally connected DVD player, but not the 5.1 connected DVD player. In that case, I would guess that your Surr Back L/R speakers would simply be silent during 5.1 operation, and no damage would occur. If they are saying that damage would occur, then I would keep shopping, as I would not consider that a well-developed receiver.

Anyway, the bottom line is that you will end up connecting the DVD player to the receiver with a digital connection (either optical or coax) and all this talk about using the 5.1 analog outs is moot.


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## Guest (Jul 9, 2007)

Thanks Otto, that helps with the questions. I didn't think I'd seen any DVD's with a 7.1 option.


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## Otto (May 18, 2006)

Nope, all that information is "created" by your receiver. Many (most?) of us haven't moved up to 7.1. For me, 5.1 really does what I need.

Good luck, and again, welcome!


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## bobgpsr (Apr 20, 2006)

Many AVRs in the mid to high end range will allow a digital S/PDIF (coax or optical Toslink) 5.1 chan DD or dts bitstream input or a HDMI 5.1 multichannel Linear PCM input to be converted to drive a 7.1 speaker set by allowing Dolby Pro Logic IIx to be applied. It recovers the back surround signals from the side surrounds by using matrix decoding. The lower end Onkyo (6xx series) and Panasonic AVRs don't allow PLIIx to be used this way but higher end Onkyo models (805, etc) do, as do most Yamaha and Denon AVRs.


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## mechman (Feb 8, 2007)

Welcome to the Shack Mike!


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## Guest (Jul 10, 2007)

Thank you, I'm reading through old threads, learning a lot. I really like the courteous "atmosphere" here at the shack, everyone is really helpful without making you feel like a moron!!!


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## John Simpson (May 10, 2007)

Heheh, yeah, the way electronics moves forward, I think all of us are perpetual morons. I'm now trying to come to grips with 9.1 and room equalisation... if they build it, we will come!

(Ummm... maybe I should rephrase that?)


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## nova (Apr 30, 2006)

Hi ya Mike, Welcome to the Shack, the friendliest HT forum on the Net. There are a lot of knowledgeable folks here and we go the extra mile to ensure a family friendly atmosphere. Glad to have you aboard.


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## jvc (Jul 15, 2007)

Hello and welcome from NC.


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## Sonnie (Apr 11, 2006)

Hello Mike and welcome to the Shack... :T

I'm gonna move this over to the General Discussion forum.


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## alan monro (May 9, 2006)

Gooday Mike , and welcome. Kind regards , Alan.:jump:


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## SierraMikeBravo (Jul 1, 2007)

Hi all,

Actually, I believe DTS ES is encoded with a 6.1 PCM signal. Yes, the receiver does add Dolby PLx II to Dobly digital and DTS signals when there is only a 5.1 stream if ou have speakers for 7.1. However, I hooked up my 7.1 system after having 5.1 for years, and I was amazed at the additional envelopment. 7.1 does make a difference!! It ws cool to A/B the two to see, and it did make a dramtic difference. It really added additional depth and wrap around effect.


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