Should subwoofers face each other? - AVS Forum
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post #1 of 9 Old 04-21-2013, 09:08 AM - Thread Starter
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I recently read someplace, that if you have them facing one another, this will allow the bass
from the subs to resonate off each other, creating a richer sound.

Any truth to that statement?

I've always had mine positioned, so that they're facing the audience.

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post #2 of 9 Old 04-21-2013, 02:47 PM
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Originally Posted by coolcat4843 View Post

I recently read someplace, that if you have them facing one another, this will allow the bass
from the subs to resonate off each other, creating a richer sound.
Any truth to that statement?
No.
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I've always had mine positioned, so that they're facing the audience.
Moot, and for the same reason why the first statement isn't true: radiation from a subwoofer is omni-directional within the subwoofer passband. What is directional is above bandwidth harmonics, and to filter them out subs work better facing the wall or downfiring. They also work better placed far apart, pretty much as far as the room allows, and I get the feeling you're probably not doing that.

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post #3 of 9 Old 04-22-2013, 03:03 AM - Thread Starter
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Quote:
Originally Posted by Bill Fitzmaurice View Post

They also work better placed far apart, pretty much as far as the room allows, and I get the feeling you're probably not doing that.

I have a subwoofer located in each corner of the room, about a foot away from the walls.
Subwoofers have a tendency to sound boomy, if they're located to close to walls.

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post #4 of 9 Old 04-22-2013, 03:24 AM
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Quote:
Originally Posted by coolcat4843 View Post

I have a subwoofer located in each corner of the room, about a foot away from the walls.
Subwoofers have a tendency to sound boomy, if they're located to close to walls.
They tend to sound boomy if the exhaust port is too close to the wall. Not the driver.

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post #5 of 9 Old 04-22-2013, 05:06 AM
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What is 'too close'?

Is it the 1/4 or 1/8 wavelength mentioned in another thread by Bill / Mark Seaton??
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post #6 of 9 Old 04-22-2013, 06:09 AM
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Quote:
Subwoofers have a tendency to sound boomy, if they're located to close to walls
Myth.
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They tend to sound boomy if the exhaust port is too close to the wall.
Also myth. Speaker placement and port placement relative to boundaries can on occasion lead to response humps, but not always by any means.
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I have a subwoofer located in each corner of the room, about a foot away from the walls
If those are the two front room corners having them there does nothing to smooth the room modes sourced by the distance to the rear wall or from ceiling bounce. One sub at the front of the room and one at the rear will help smooth both of those modes. More precise placement requires measuring the in-room response.

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post #7 of 9 Old 04-23-2013, 08:57 PM
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Quote:
Originally Posted by Bill Fitzmaurice View Post


(subs facing each other makes them work better) Also myth. Speaker placement and port placement relative to boundaries can on occasion lead to response humps, but not always by any means.
If those are the two front room corners having them there does nothing to smooth the room modes sourced by the distance to the rear wall or from ceiling bounce. One sub at the front of the room and one at the rear will help smooth both of those modes. More precise placement requires measuring the in-room response.

A theoretical question for you, Bill (or others who are smarter than me, which is most everybody).

I would think having subs directly opposing each other would cause the sound waves to cancel each other down, knocking down the sound as it were. I think of it the same way two boats would pass each other in opposite directions, when the the waves behind each boat reach each other, both waves are dissipated (I live by a river rolleyes.gif)

My question is, what if one of the subs were 180 degrees out of phase and facing each other? It seems to me the sounds now would be working WITH each other, each driver pushing and pulling in sync with one another. That's all between my ears, I have no practical knowledge or experience to validate my guess on that.

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post #8 of 9 Old 04-24-2013, 05:37 AM
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Originally Posted by wvu80 View Post

I would think having subs directly opposing each other would cause the sound waves to cancel each other down, knocking down the sound as it were.
Look up the definition of 'omni-directional'. It doesn't matter which way the subs are facing, the result is the same because their output is not directional. As for cancellation, that will occur where the distance differential from the subs to the listening position is 1/2 wavelength and there are no boundary reflections. Since there are so many boundary reflections in an average room and the distances to the boundaries are relatively short compared to those of subwoofer pass band wavelengths cancellation issues in HT tend to be minor, and are far overshadowed by room modes.
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My question is, what if one of the subs were 180 degrees out of phase... It seems to me the sounds now would be working WITH each other, each driver pushing and pulling in sync with one another.
That scenario is what would cause cancellation. You can't pressurize a room if you have one source putting air into it while another sucks it out.

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post #9 of 9 Old 04-25-2013, 04:29 PM
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Also see using subwoofers in room mode canceling arrangements


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