Sanjay, great explanation of the reversal effect. It's something I hadn't really considered but once you described it I know exactly what you are talking about.

Anyway, I'm one of those poor souls who has to have the listening seats up against the back wall so I have eschewed rear surrounds for now. What I'm wondering is have any of you outlaws tried putting the rear surround speakers on/in the ceiling and maybe aiming them at the back wall (or not)? It might be difficult to set up something to experiment with but my intuition tells me it might be somewhat effective. Granted it would be less than ideal, but I'm just wondering if anyone has some first hand experience with anything like that.

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Tekdredger

I'm currently running dipoles on the rear and direct radiators on the sides because I can't mount my dipoles on the sides - room limitations. I do prefer dipoles on the sides. As for the rears, I really like the effect I get from dipoles back there. Direct radiators would probably work equally well, but I wouldn't rule out dipoles in the rear.

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gonk -- 950 Review | LFM-1 Review | Pre/Pro Comparison Chart | Saloon Links

my bad, i edited that post above...

7.1 IS primarily for larger listening areas (typically meaning larger rooms), and is not significantly different than 6.1. to clarify what i agreed with and what i did not... however, if one is thinking more than 5.1, 7.1 is the way to go.

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rears in the ceiling is a bad idea.

ear level is always best, and until they come out with a channel that is supposed to be in the ceiling or floor, the effects do not sound right coming from above (below either) or reflecting off of another wall.

many reasons why, so little time to explain them all! :-)

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What does room size have to do with 7.1 set-ups? Roughly how big does a room have to be before you can start considering 7.1? The difference is significant, as I explained above. I guess you don't think there's a significant difference between "sucks" and "preferred", which is how you yourself described 6.1 and 7.1 respectively.

BTW, companies that historically have been on the cutting edge of surround sound (Meridian, Lexicon, Fosgate) have built their surround processing technologies around a 7.1 set-up, not 6.1. They all wouldn't have done that if the difference wasn't significant.

Anyway, I guess it doesn't leave much in my original post for you to agree with.

Best,
Sanjay

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Tekdredger

Originally posted by sdurani:
What does room size have to do with 7.1 set-ups? Roughly how big does a room have to be before you can start considering 7.1?

That is a silly set of questions. To benefit at all from surround sound, there needs to be separation between each channel. If you were sitting on a stool with each speaker right beside you, you would not hear surround sound, you would just hear a lot of sound. Surround sound is meant to provide localized sounds. I suppose you are nit-picking, but that is what room size has to do with surround sound in general and specifically 7.1 vs 5.1 vs 2.1, etc.

Likewise if you were at a movie theater, and it only had 5.1, or 7.1 for that matter, there would be huge areas with less than optimal surround sound effects. Why, because depending on where you sat, you could behind the last set of speakers or if the speakers were placed in the corners, then the distance would be too great to reveal the surround effect.

Obviously, most people dont have an enormous area, such as a movie theater, but it is an example of size and why it is relevant.

Room acoustics play a large part in sound reproduction, besides merely size...

As for a specific size, I doubt there is one. Speakers/other gear dictate the specifics.

There is a bunch of technical info, on correct speaker placement, etc. which is all relative to room size and listening area. Each situation requiring a different setup.

I am not going to specify a room size because, a total sf is not all that is relevant. Length and width in relation to listening position are key.

Give me a break.

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This post has been brought to you by curegeorg, thanks for reading.

Like Tekdredger, I had been considering mounting the rear surrounds on the ceiling with them firing at the back wall, since my seating is also against the back wall. It seemed like it might work, but I was unsure if my ears would pick up the sound from the speakers before the reflected sound, really screwing up the directional aspects of the surround sound. Another option was using in-walls for the rear surrounds. Again, not perfect but maybe effective. Has anyone tried this or have any comments?

The first room I had available for surround sound was small and the couch was against the rear wall. The only place for rear speakers was in the upper horizontal corner between rear wall and ceiling. I used small steel cable and small eyelets (eyelets into wood, not drywall) to support the speakers at almost 45° in the 90° corner. The surround effects blended quite well, even in this position relative to the listeners.

Separation between channels doesn't have to be done with distance alone. It can also be done with angles.

I've listened to a system made of 7 nearfield monitors, all of which were little more than arm's length away. There was no problem with localization; especially in the surround field, where I heard solid rear vs side separation.

Despite the close proximity of the speakers, most listeners could localize sounds at their sides vs sounds behind them. The difference in direction is easy to spot. Even moreso when they are listening to speakers physically at those locations rather than relying on phantom imaging. I still respectfully disagree with you, and it's not for nitpicking sake. I've seen too many people discouraged from doing fine 7.1 set-ups because they were led to believe that their room falls below some size threshold.

As I said earlier, if you're in a large room but your couch is against the back wall, your situation is not conducive to a 7.1 set-up. But you could be in a small room and be sitting near the middle and have an excellent 7.1 system. Size is not the deciding factor, seating location and how much room you have behind you is what matters most.

Lateral sounds should come from your sides, surround-back content should come from behind you. There's no reason why this should hold true for large rooms but not small ones. Please understand, I'm not saying this to be nitpicky or give you a hard time. I've just never seen a size threshold applied to 5.1 vs 7.1. OK, you can take 15 minutes. But then it's back to posting.

Best,
Sanjay