# Speaker placement issue



## Upstairs Cinema (May 18, 2010)

Hey all,

I am stuck in figuring out the placement for my LR speakers. I was looking at placing them all behind the screen, but that puts them a mere 2'5" out from the Center channel (35.8 degree spread to the center seat). That also has them on the very edge of the screen frame, and im not sure how bad that affects the dispersion. Seems like not enough space for pans across the front channels. My other option would be to put them outside the screen, and that would put them WAY out (58 degrees) and near the side walls. Which is better?

Heres my setup. Highlight is the 126" screen itself. Blocks to either side are the width of the Masquerade masking.


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## tonyvdb (Sep 5, 2007)

You've got lots of room on either side of the screen to either build them into the walls or simply place them in the room (the better choice) just do not push them into the corners. Looking at your drawing your side surrounds are too far back. They should be beside the front row of seats not behind them.


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## Upstairs Cinema (May 18, 2010)

tonyvdb said:


> You've got lots of room on either side of the screen to either build them into the walls or simply place them in the room (the better choice) just do not push them into the corners. Looking at your drawing your side surrounds are too far back. They should be beside the front row of seats not behind them.


Hrmm perhaps i can build them into the screenwall. that would put them close to the side walls though. 

The side surrounds are within THX spec. With multiple rows of seats its better to have them between the rows.


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## tonyvdb (Sep 5, 2007)

Upstairs Cinema said:


> Hrmm perhaps i can build them into the screenwall. that would put them close to the side walls though.


As long as they are at least 16" away from the side walls you will be fine.



> The side surrounds are within THX spec. With multiple rows of seats its better to have them between the rows.


That is only true if you are running a 5.1 system. It sounds better if they are even with the listeners ears in the front row in a 7.1 setup.


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## bpape (Sep 14, 2006)

The starting rule of thumb is an equilateral triangle which has the L, R, and head included angle at 60 degrees (30 to the left and 30 to the right.

I hope the wall you're building is acoustically transparent as putting speakers in a hard wall is not a good idea unless they're specifically designed to be in-walls. It will completely change the upper bass and lower mids by effectively making the entire wall the new speaker baffle.

Bryan


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## Upstairs Cinema (May 18, 2010)

bpape said:


> The starting rule of thumb is an equilateral triangle which has the L, R, and head included angle at 60 degrees (30 to the left and 30 to the right.
> 
> I hope the wall you're building is acoustically transparent as putting speakers in a hard wall is not a good idea unless they're specifically designed to be in-walls. It will completely change the upper bass and lower mids by effectively making the entire wall the new speaker baffle.
> 
> Bryan


I hear ya on the triangle. I'm able to get all speakers in ideal positions except for the fronts. Just cant figure out the best compromise. 

The picture is a little misleading. the outer line of the room is where the wall is now. the inner represents DD+GG, clips, and 4" of acoustic treatement. The speakers arent actually in the wall, they are sunk 2 1/4" into the 4" of deadening. Im not even sure 4" is necessary, but im using that as the rule all the way around the room to ensure proper clearances after all soundproofing/acoustic paneling is in. That is why the columns look sunk in as well. They are merely attached to the wall with 4" of paneling on either side.

If the speakers are on the outside of the screen, they would be within a foot of the sidewalls.


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## SierraMikeBravo (Jul 1, 2007)

Upstairs Cinema said:


> Hrmm perhaps i can build them into the screenwall. that would put them close to the side walls though.
> 
> The side surrounds are within THX spec. With multiple rows of seats its better to have them between the rows.


Do you have a reference for this?


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## Upstairs Cinema (May 18, 2010)

SierraMikeBravo said:


> Do you have a reference for this?


For the side surrounds? The THX site says that the sides should be between 90-110 degrees of the listening location. Mine are 103. I could be wrong, but placement is tricky due to a door.


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## bpape (Sep 14, 2006)

Surrounds are VERY dependent on whether you're doing 5.1 or 7.1

Bryan


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## Upstairs Cinema (May 18, 2010)

bpape said:


> Surrounds are VERY dependent on whether you're doing 5.1 or 7.1
> 
> Bryan


Absolutely. This was the listing for 7.1. You know more than I. If it is terrible, Ill see what can move around. This is my rough starting point and the best I could make it.


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## bpape (Sep 14, 2006)

Those positions look good to me. The biggest thing is to get the seating in the right places before you figure the speakers. Usually, the best place for the front row seated ear positions is between 62 and 66% of the room length. 

Surrounds between the rows is a good compromise. If it were me, I'd spread the rear surrounds a bit farther apart.

Bryan


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