# Using a 2nd center channel



## harleyhualer-sc02 (May 25, 2008)

I know many people have asked this question about putting a center channel above and below the screen, or either side left and right and everyone advises against it . But what about a 2nd center channel facing to the rear? Using it as a bi-pole or dipole. Would this work or sound bad ?


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## lsiberian (Mar 24, 2009)

harleyhualer-sc02 said:


> I know many people have asked this question about putting a center channel above and below the screen, or either side left and right and everyone advises against it . But what about a 2nd center channel facing to the rear? Using it as a bi-pole or dipole. Would this work or sound bad ?


The only place for a 2nd center is in a stadium seating theater.


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## harleyhualer-sc02 (May 25, 2008)

So in other words your saying there shouldn't be a 2nd center channel in an average home theater no matter how you place it.


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## tonyvdb (Sep 5, 2007)

Thats correct, adding another duplicate speaker to any channel will cause more issues than fix due to cancellation or strange combing affects. If your not getting enough out of your current center channel you either need to turn it up or get a larger one.


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## harleyhualer-sc02 (May 25, 2008)

getting a bigger center means getting bigger main channels to keep everything balanced.

What about buying a cheap 8" or 10" powered sub and run the center crossed over higher like 150-200 hz to run more power to it? Let the sub take care of like 40hz to 150-200 hz


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## tonyvdb (Sep 5, 2007)

harleyhualer-sc02 said:


> What about buying a cheap 8" or 10" powered sub and run the center crossed over higher like 150-200 hz to run more power to it? Let the sub take care of like 40hz to 150-200 hz


Are you saying you dont have a sub already?
How large a room is this system in?
and finally what are you using for speakers?


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## Matteo (Jul 12, 2006)

harleyhualer-sc02 said:


> getting a bigger center means getting bigger main channels to keep everything balanced.



Not necessarily. A lot of people who buy a "package" set of speakers upgrade the center channel. I agree with Tony though, we need some more information.

Matteo


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## harleyhualer-sc02 (May 25, 2008)

Reciever- Onkyo tx-nr1007 9.2/11.2
Speakers- AV123 ELT525's 8-towers 3 center(2 centers used for front height)
Subs- 4 18" Mal-X's and 8-PR's powered by 4- EP2500's

I currently don't have the subs hooked up yet. A local cabinet builder just started building the enclosures. Even without the subs I can tell the center is lacking. All in a 20'L x 20'W x 9.5'H converted garage.


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## tonyvdb (Sep 5, 2007)

harleyhualer-sc02 said:


> I currently don't have the subs hooked up yet. A local cabinet builder just started building the enclosures. Even without the subs I can tell the center is lacking. All in a 20'L x 20'W x 9.5'H converted garage.


You will notice once you have your subs in place it will help allot, My biggest issue is the dimensions of the space, a 20'x 20' square is very bad for acoustics. That actually could be some of your problem right now. due to the reflection points being all the same in a square room you will get a fair bit of cancellation particularly if your seating is near the center of the room.


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## harleyhualer-sc02 (May 25, 2008)

I was thinking it would get even worse once I added the subs from the added low end. My seating for right now is about 7' away from the rear wall.


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## tonyvdb (Sep 5, 2007)

Your going to need to do some very serious acoustic dampening with panels and traps around that room. Your seating is very close to center and that in its self will also cause issues. Its a tough room to work with.


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## lsiberian (Mar 24, 2009)

Let's not get carried away with treatments here. 

Certainly treat the backwall with diffusers in the corners and dampening on the rear wall. Avoid treatment in other areas as much as you can. 

The safest channel to duplicate are the surrounds, but in a room that small it's a waste. 

For your sub put one on the front mid and one on the back midwall for the most even response.


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## harleyhualer-sc02 (May 25, 2008)

My front wall will have the tv in a 14' wide entertainment center and 2 subs were going to be placed on either side. Its actualy going to be 4 subs one in each corner of the room. Is this placement for the subs I have planned unwise as far as the shape of my room is concerned? Also the back wall is 16' wide of glass patio doors, that I plan to put heavy drapes on. This will block out sunlight and hopefully help out with the acoustics.
_Posted via Mobile Device_


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## lsiberian (Mar 24, 2009)

harleyhualer-sc02 said:


> My front wall will have the tv in a 14' wide entertainment center and 2 subs were going to be placed on either side. Its actualy going to be 4 subs one in each corner of the room. Is this placement for the subs I have planned unwise as far as the shape of my room is concerned? Also the back wall is 16' wide of glass patio doors, that I plan to put heavy drapes on. This will block out sunlight and hopefully help out with the acoustics.
> _Posted via Mobile Device_


Drapes are what they use in the theater. So you it should work fine. Just make sure you get some shelves in corner area because it helps with the surround field. 

Dual subs are best place on opposing room sides to cancel the room modes. Is it possible to put the subs on the side walls? 

Having them beside either side of the TV will help with some modes, but excite others more.


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## Kal Rubinson (Aug 3, 2006)

lsiberian said:


> Drapes are what they use in the theater. So you it should work fine.


Drapes are what they use in the theater to cover the screen when the show is over. Heavy drapes will help with high frequencies but unless they are purpose-designed (e.g., lead-lined) they will do nothing for low frequencies.


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## harleyhualer-sc02 (May 25, 2008)

lsiberian said:


> Drapes are what they use in the theater. So you it should work fine. Just make sure you get some shelves in corner area because it helps with the surround field.
> 
> Dual subs are best place on opposing room sides to cancel the room modes. Is it possible to put the subs on the side walls?
> 
> Having them beside either side of the TV will help with some modes, but excite others more.


Are you suggesting to put all 4 subs on the side walls?


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## recruit (May 9, 2009)

In studios they often stack monitors for recording soundtracks, if you have a dedicated Home Theatre with an acoustically transparent screen then it is a good idea but you also need the extra power to drive them, I remember M&K giving demo's with stacked S150's and they sounded pretty amazing !


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## harleyhualer-sc02 (May 25, 2008)

my plan was to buy a seprate 2 channel amp ran off the center channel preout. I'm sure they're a number of speakers out there that can be stack without ill effects. but those speakers where probably designed to be stack without ill effects. jbl makes a ton of pro audio speaker that are designed to be stack line arrays.
_Posted via Mobile Device_


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