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Thread: 5.1 to 7.1

  1. #1
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    5.1 to 7.1

    Your inputs,
    I'm very happy with my 5.1 home theater set up but since my receiver has 7.1. I'm thinking adding 2 more rear speakers to experience the 7.1
    What's the advantage of 7.1 over 5.1? Which format will play 7.1?
    Perhalps, 6.1 is my other option. It's cheaper.

  2. #2
    Da Dragonball Kid L.J.'s Avatar
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    Quote Originally Posted by gjpham
    Your inputs,
    I'm very happy with my 5.1 home theater set up but since my receiver has 7.1. I'm thinking adding 2 more rear speakers to experience the 7.1
    What's the advantage of 7.1 over 5.1? Which format will play 7.1?
    Perhalps, 6.1 is my other option. It's cheaper.
    There are not any discrete 7.1 formats to play, but your AVR will matrix the surround back chann. There is a handfull of discrete 6.1 though. I've had both setups and 5.1 is just as enjoyable as 7.1. I'd make sure my 5.1 was setup properly and optimized before throwing money on SB's. You also need to make sure you have enough room for that type of setup.

    Here's and article on proper placement of a 5.1/7.1 system and a guide on current surround formats.

    7.1 placement
    Surround formats

  3. #3
    ride a jet ski Tarheel_'s Avatar
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    to echo L.J....check your setup and room first.

    I moved up to 7.1 and enjoy the additional speakers when using the non-digital surrounds like Neo and Logic 7 for watching hockey and all TV shows. DVDs..well, i can't really say there is much difference...every once in a while i hear something from them, but mainly they just blend in with the sides.

  4. #4
    Forum Regular N. Abstentia's Avatar
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    Personally...I couldn't find any reasons to go to a 7.1 setup. To me the biggest disadvantage to 7.1 (other than the room size and speaker placement requirements) was the fact that when you play 5.1 through a 7.1 system then the side surrounds (NOT the rears) are your only surrounds. Useless.

  5. #5
    Loving This kexodusc's Avatar
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    Quote Originally Posted by N. Abstentia
    Personally...I couldn't find any reasons to go to a 7.1 setup. To me the biggest disadvantage to 7.1 (other than the room size and speaker placement requirements) was the fact that when you play 5.1 through a 7.1 system then the side surrounds (NOT the rears) are your only surrounds. Useless.
    Huh?
    That's not true at all. Bad info. Who told you that?

    7.1 expands on 5.1 even with 5.1 discrete inputs. In 5.1, there's plenty of info that's fed to the side surrounds to create a rear center image...similar to a front center image during stereo playback. It's often lost in 5.1 mode, or at least not as pronounced as it should be. 7.1 uses those same sound cues, but just uses them much, much better so the sound is anchored and much more dimensional.

    The side surrounds don't lose anything as far as I know...

    On my setup I find the improvement quite noticeable. Previous placement requirements of my side surrounds forced me to set them several feet behind and angled towards my listening position to get best results. Just having them on the sides sucked for multi-channel music, and sometimes left a hole in the surround field behind. Adding a couple rears solved this. Now that I have it, I find 5.1 insufficient. Just engaging the processor for instant a/b comparisons really establishes the increased 360 degrees of depth, and improved the side performance as well.

    I still thing a good 5.1 system is better than a rushed 7.1 system, but a properly setup 7.1 system is killer.

    I'd avoid 6.1. I tried this briefly for about 2 months. One speaker does not do an adequate job at creating a diffuse rear surround field. Instead it tends to pin-point rear sound cues, and I found the total sound field collapsed backwards a bit, as opposed to just expanding outward.

    As was mentioned, if you don't have at least 3 or 4 feet behind your listening position (and preferably more) 7.1 really isn't an option...get 5.1 down pat first.

  6. #6
    Forum Regular paul_pci's Avatar
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    Well, two of the four surround speakers have to be matrixed from the native 5.1 encoding to fill out the 7.1 set up. So, which is it? Which speakers get the matrixed sound to cover the soundfield? the back 2 surround speakers or the side surround speakers?

  7. #7
    ride a jet ski Tarheel_'s Avatar
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    it's my understanding the side surrounds receive the discrete signal and the surround rears receive the matrixed stream.

    I gotta go with Kex on this one...the added 2 speakers do create a more seamless surround, but you must have the room. my side surrounds are slightly behind my listening position and also angled slighly down (they are not bi or dipole) and the rear surrounds are still about 6 feet from my position at the same height.
    I've also done the a/b compairson and always prefer the 7.1, especially for sports. DVD movies, i don't get the same improvement, but still leave it in 7.1 mode. Only format i don't have is PL IIx, but do play with the others.

  8. #8
    Loving This kexodusc's Avatar
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    Quote Originally Posted by paul_pci
    Well, two of the four surround speakers have to be matrixed from the native 5.1 encoding to fill out the 7.1 set up. So, which is it? Which speakers get the matrixed sound to cover the soundfield? the back 2 surround speakers or the side surround speakers?
    The side surrounds continue to receive their respective discrete signals..shared info receives the matrixed processing and is moved to the back some, but doesn't get completely removed from the sides. The word "matrix" comes from the complex algorithm involved in the process. I don't expect it's perfect, but the processing was designed to better represent what we should be hearing. It's not a best guess, but rather the result of years of testing of how best to deliver the information.

    With PLIIx, it's much more complex. I don't know how it's further expanded on, but I do know it is far superior to ProLogic. The biggest improvement is the additional ambience provided. You are totally engulfed in a surround field.

    I remember when I was selling my Studio 20's, I went back to 5.1 for a few months, what a letdown. In my opinion the additional benefit from 7.1 over 5.1 is almost as big as what one would experience adding a two surrounds to a L/C/R combo to get 5.1. Not quite, as much. It's not the most cost effective performance upgrade, still well worth it if your room provides for it.

    On the negative side, there are a few cases where I've found the surround field has been pulled backward at the expense of the left and right surround fields. I notice this mostly on concert DVD's. Best I can describe the effect is that you move from being in the middle of the crowd the crowd along the front/back axis in 5.1 to moving forward a bit, like up a few rows so there's more crowd behind you...the place sounds deeper overall, but more of the crowd sounds behind you than from side to side. I still prefer engaging the 7.1 processing here, but it doesn't seem to be as effective as with most movies. I suspect the fact that so much "crowd noise" is being fed the two surround channels in the 5.1 mix that processing just shares it across all 4 surround channels evenly.

  9. #9
    Silence of the spam Site Moderator Geoffcin's Avatar
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    The first thing to ask yourself is;

    Quote Originally Posted by gjpham
    Your inputs,
    I'm very happy with my 5.1 home theater set up but since my receiver has 7.1. I'm thinking adding 2 more rear speakers to experience the 7.1
    What's the advantage of 7.1 over 5.1? Which format will play 7.1?
    Perhalps, 6.1 is my other option. It's cheaper.
    Do I have the room to do a 7.1 system?

    My HT room is 22' X 16' and it was/is about a minimum size that I would consider needed for a 7.1 system. The reason is that you want the rear surrounds at least 4ft from your head, or you will have localization problems. I would say, that if you DO have a room of this size then a 7.1 system makes a lot of sense.

    The rear surround speakers, although not a discrete signal (except for DTS-ES encoded disks), do add a lot of subtle audio cues that you would find in a cinema that are not fully realized in a 5.1 system. I find it adds debth to the surrpund soundfield on most movies, especially ones with a rich soundtrack. I DO agree that on concert DVDs it's a bit annoying to have people clapping behind your head, but that's the price you pay for added realism!
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  10. #10
    Forum Regular N. Abstentia's Avatar
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    Quote Originally Posted by kexodusc
    Huh?
    That's not true at all. Bad info. Who told you that?
    I forget where I read it, (possibly even in the manual for my 7.1 receiver) but when I was wiring my new system I did seek out the info.

    The info I got was that when you play something in 5.1 (like SACD) through a 7.1 system, the side speakers are your surrounds and not the rears.

  11. #11
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    Quote Originally Posted by N. Abstentia
    I forget where I read it, (possibly even in the manual for my 7.1 receiver) but when I was wiring my new system I did seek out the info.

    The info I got was that when you play something in 5.1 (like SACD) through a 7.1 system, the side speakers are your surrounds and not the rears.
    Any modern receiver worth its salt will allow the user to engage processing for 5.1 discrete signals (exluding analog inputs from SACD/DVD-A of course), so they're in use almost always. As far as I know all EX/ES processors do this. I've never seen one that couldn't.

    As I said, it's much more than just adding rears, in most setups I've heard, it allows re-positioning of the side surrounds to an even better place to improve on the sides and back.

    What I decided on doing after about 3 months of experimenting was position the rears back, but far enough apart to be used for SACD/DVD-A in the ITU 5.1 setup...then the sides are almost perfectly in line with my head.
    All takes is wiring the analog outs from my SACD/DVD-A player to the 6th and 7th channels instead of the 4th and 5th...works great. When I sold the first pair of Studio 20's, I had to lose the ones beside me so I could still listen to multi-channel audio. They were sort of in the rear corners opposite the front mains, toed-in quite a bit. The surround effects for movies really took a beating compared to the 7.1 setup.. In my 5.1 systems that's where I always preferred them. It was either have the side surround field a bit weak, or a more gaping hole in the back. Placing them further back was the best compromise. It never sounded right with the surrounds beside my head like Dolby recommends. But it sure made a difference adding the extra 2 channels...it's cool having things really wizz past your head from front to back in a more seamless progression.

    It's a tough call for a lot of people. Another set of Studio 20's cost me $600 to get the extra speakers. It was worth it to me, but probably not to everyone. For people starting out, I think they're further ahead to do 5.1 better than a 2nd rate 7.1.
    Last edited by kexodusc; 04-09-2006 at 07:35 AM.

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