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Best spot for rear surrounds in my room

post #1 of 16
2/11/09 at 11:45am
Thread Starter 
I want to upgrade my home theater speakers. But before I decide what to buy, I need to know where is the best spot to mount the 2 rear surrounds, and what type to buy(bookshelf, bipole or dipole). My ears are about 2' from rear wall when seated. I know it's not ideal, but where would you mount the 2 rear surrounds? I do not want ceiling speakers. Because of this situation, I don't know whether to use bookshelf speakers on each side, dipoles or bipoles on sides or rear wall. Thanks.
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post #2 of 16
2/11/09 at 12:35pm
If you are talking about the left/right "surround" speakers in a 5.1 system, the Dolby recommendation is to the sides, directly to your left and right or up to 20-degrees back from that, slightly over your shoulders.



If you are talking about the left/right "back" speakers in a 7.1 system, the same Dolby recommendation is between 45 to 60-degrees behind you.

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post #3 of 16
2/11/09 at 1:13pm
Thread Starter 
Thanks cavu. It's a 5.1 setup. I know what the Dolby recommendations are, but is there a better way to do it in my room? The back of my couch is just a few inches from rear wall, and I can't move it forward because it's on a riser. The side surround would be virtually right up against rear wall. This is why I'm considering the omni-directional Mirage Nanosat speakers. Would a dipole or bipole surround work better(since my couch is so close to rear wall)? If so, what type, and should they be mounted on side wall or rear wall? When I'm seated on the couch, my ears are about 2' from rear wall. Thanks.
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post #4 of 16
2/11/09 at 9:51pm
Quote:
Originally Posted by Jim McC View Post

Thanks cavu. It's a 5.1 setup. I know what the Dolby recommendations are, but is there a better way to do it in my room? The back of my couch is just a few inches from rear wall, and I can't move it forward because it's on a riser. The side surround would be virtually right up against rear wall. This is why I'm considering the omni-directional Mirage Nanosat speakers. Would a dipole or bipole surround work better(since my couch is so close to rear wall)? If so, what type, and should they be mounted on side wall or rear wall? When I'm seated on the couch, my ears are about 2' from rear wall. Thanks.

My couch is right up against the back wall, so my surrounds were firing right at the listener. I would suggest in your situation dipoles would be worth considering. However, with that said, Chris at Audyssey gave me a slightly radical suggestion of placing the surrounds on their backs, firing up towards the ceiling. I must say it has greatly improved the surround field!
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post #5 of 16
2/11/09 at 11:26pm
Thread Starter 
Are you suggesting dipoles on the side walls? How are your surrounds mounted? Are they sitting on a shelf pointing up? Are they bookshelf speakers? Thanks.
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post #6 of 16
2/12/09 at 6:57am
Another suggestion would be directs, firing across the room at each other, right on the back wall but higher up, a few feet above ear level...
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post #7 of 16
2/12/09 at 11:25am
Thread Starter 
Quote:
Originally Posted by glaufman View Post

Another suggestion would be directs, firing across the room at each other, right on the back wall but higher up, a few feet above ear level...

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I'm aware of this option, but there's another problem I should have listed. On the right side, there's a boxed-in post that's would block the sound. One thought was to mount a dipole on the boxed-in post, and the other dipole on the opposite side wall. Another thought was to use bipoles on the rear wall. My third option would be to use normal bookshelf speakers near the rear corners pointing inward(mounting the right one on rear wall so post is not in the way). Any opinions? Thanks.
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post #8 of 16
2/12/09 at 11:39am
Quote:
Originally Posted by Was_There_Then View Post

Chris at Audyssey gave me a slightly radical suggestion of placing the surrounds on their backs, firing up towards the ceiling. I must say it has greatly improved the surround field!

Some people think some of my ideas are radical and even stupid. I'd have to say Chris's ideal certainly takes the cake for being radical and even stupid. Why even bother making a speaker cabinet and drivers out of good materials, making them phase coherent, and tuning their frequency response to be as flat as possible if you're just gonna F it all up by pointing it no where near your ears and listen to only the reflected sound off the walls and ceiling? Yeah, I bet it creates more of a sound "field" for sure. Heck why don't we just all point our main speakers at the back wall too so you can have a left and right field and a center field. I can come up with a whole bunch of great ideas like that one. I think I'm qualified to work at Audessey too.
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post #9 of 16
2/12/09 at 12:04pm
Quote:
Originally Posted by Jim McC View Post

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I'm aware of this option, but there's another problem I should have listed. On the right side, there's a boxed-in post that's would block the sound. One thought was to mount a dipole on the boxed-in post, and the other dipole on the opposite side wall. Another thought was to use bipoles on the rear wall. My third option would be to use normal bookshelf speakers near the rear corners pointing inward(mounting the right one on rear wall so post is not in the way). Any opinions? Thanks.

Can we get a drawing/sketch?
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post #10 of 16
2/12/09 at 1:53pm
Thread Starter 
Quote:
Originally Posted by glaufman View Post

Can we get a drawing/sketch?

I would if I knew how.
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post #11 of 16
2/12/09 at 2:09pm
I don't understand the problem? Why can you not simply place the speakers to the sides and slightly behind the couch, aimed toward the sweet spot, per the Dolby recommendation?
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post #12 of 16
2/12/09 at 2:53pm
Quote:
Originally Posted by Mr. Audio View Post

Some people think some of my ideas are radical and even stupid. I'd have to say Chris's ideal certainly takes the cake for being radical and even stupid. Why even bother making a speaker cabinet and drivers out of good materials, making them phase coherent, and tuning their frequency response to be as flat as possible if you're just gonna F it all up by pointing it no where near your ears and listen to only the reflected sound off the walls and ceiling? Yeah, I bet it creates more of a sound "field" for sure. Heck why don't we just all point our main speakers at the back wall too so you can have a left and right field and a center field. I can come up with a whole bunch of great ideas like that one. I think I'm qualified to work at Audessey too.


In response:
Quote:
Originally Posted by Audyssey View Post

This is certainly not a general recommendation. It was a very special case in which the speakers could only be placed very close to the couch and were thus overwhelming as point sources for surround content. Ideally, one would use dipoles to achieve the diffuse surround field for which movies are mixed. This was a simple way to get the speakers to point their main lobe in another direction.

Of course, there is HF attenuation as a result. For surround movie content, however, I think that diffuse field is more important so this is a good tradeoff.

It's a matter of choosing the lesser of two evils. The best solution for ambient enveloping surround for movie content is to use dipole speakers. If that's not possible, then I think envelopment is more important than frequency response for surround speakers. Hence my recommendation.
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post #13 of 16
2/12/09 at 3:24pm
Thread Starter 
Quote:
Originally Posted by sivadselim View Post

I don't understand the problem? Why can you not simply place the speakers to the sides and slightly behind the couch, aimed toward the sweet spot, per the Dolby recommendation?

Like I said in post #7, between the couch and right side wall there's a boxed-in post that would block the sound. That's why I can't mount a speaker on the right wall. The right speaker would have to be mounted on rear wall and angled in. Since we sometimes have people sitting in front of couch on portable chairs, I thought using dipole/bipoles would be the best way for everyone to hear the surrounds.
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post #14 of 16
2/12/09 at 9:27pm
Quote:
Of course, there is HF attenuation as a result. For surround movie content, however, I think that diffuse field is more important so this is a good tradeoff.

It's a matter of choosing the lesser of two evils. The best solution for ambient enveloping surround for movie content is to use dipole speakers. If that's not possible, then I think envelopment is more important than frequency response for surround speakers. Hence my recommendation.

Still the idea is a horrible one. One of the reasons why Audessey and others like it exists is to help match the speakers with each other to compensate for differences caused by room acoustics and perhaps mixed brand speakers and help make speaker transitions seamless. Pointing speakers directly at walls or ceilings will definitely spread the sound around the general area but it will sound totally different from the front and transition from front to back will be far from seamless. I have a better idea. One, move the surround speakers as far away from the listening position as possible. Two, use the distance controls on the receiver. Between those two, you will have natural seamless transition and definition in the surround channels. If you have a large area to cover, use dipoles or several direct speakers.
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post #15 of 16
2/13/09 at 7:27am
Despite the Dolby recomendations, dipoles are the recommended geometry from THX for the surrounds, so you're on the right track there... if you can put them so the null is pointing at your listening position(s), their tweeters are at least a foot above ear heigh, the top of the cabinet is at least a foot below the ceiling, and you're post isn't in the way of the radiated sound (don't forget any ports that may/not be there) then you'll be doing ok once calibrated...
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post #16 of 16
2/13/09 at 11:39am
Thread Starter 
On the right side of the room, there's the boxed-in post between me and the wall. If I put a bipole or dipole on the post, would that work? I know they're supposed to be on a wall. Between the right wall, rear wall, and the post there's about 2 feet. The post is lined up with my ears when seated, so the null would point right at me. My other option was to mount a bipole or dipole on the rear wall. Any ideas?
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