# Subs Facing Each Other



## RPercival (Sep 21, 2011)

I have the subs in my car facing each other in separate boxes right now. It's plenty damn loud and I don't think there is an issue but I've been wrong before. I've heard a lot about cancellation and whatnot but my system seems to be just fine. I've tried facing them both rearward and it actually seemed quieter. Any input on this? Am I crazy or can subs facing each other work?


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## ZAKOH (Nov 26, 2010)

I have no idea which is best, but here is a picture of Scott Buwalda's show car with four 6.5 inch subs facing each other:

Buwalda Hybrids International Bulletin Board • View topic - New Project Car to Introduce: Scott's G35


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## minbari (Mar 3, 2011)

as long as the front waves of the subs are in phase with referance to each other. it wont matter. the wave lengths we are talking about here, it makes little difference.


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## pionkej (Feb 29, 2008)

minbari said:


> as long as the front waves of the subs are in phase with referance to each other. it wont matter. the wave lengths we are talking about here, it makes little difference.


This is the correct answer.

EDIT: For a bit more detail though... 

You can put your subs facing into a corner and "load" them for more output. I'm not fond of it because it usually causes more problems than it solves. You usually end up with a single peaked frequency and everything sounds a bit "muddy". Look at home audio. I have a average HTIB (Home Theater in a Box) in my living room with a 10" ported sub. It sits in the coner "loaded" and at 50-60hz, it will match the output of my dual 15" JBL GTi subs on 1000w in my bonus room. The problem is that everything else sounds like crap! The bonus room setup is 1000000000x closer to what you hear at an actual theater compared to the HTIB.


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## minbari (Mar 3, 2011)

Ninebreaker said:


> So this means I'd have to have one sub at 0 degrees and the other at 180 degrees?
> 
> One sub has to be pushing out while the other pulling in during the same note at a given point?


no, both at 0°. this is no different that if they face the same direction, makes no difference. if you put one of them at 180°, then they will cancel like crazy.

technically you should put them 90° out of phase from each other, but unless you have a phase controller, you wont be able to do this. only time you have to put a sub 180° out of phase is if one sub is backwards. (1 sub inverted in the box or subs mounted at opposite side of the box, front to back.)


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## pionkej (Feb 29, 2008)

Ninebreaker said:


> So this means I'd have to have one sub at 0 degrees and the other at 180 degrees?
> 
> One sub has to be pushing out while the other pulling in during the same note at a given point?


EDIT: minbari has it right above. Information below is still useful IMHO so it stays. 

You also need to consider the actual length of the notes your sub is playing. At 80hz the length is over 14ft (13500/80/12) and over 50ft for 20hz! At those frequencies, the entire cabin is pressurized and therefore the cabin is contributing as much interference as another sub would. Again, just aim them where they sound best and rock it.

Formula: (Speed of sound/frequency/12)

You divide by 12 to convert inches to feet.


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## minbari (Mar 3, 2011)

another thing to consider is the phase response of a sub is all over the place. so a slight phase variance in where you place them is not going to make much difference in a car.


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## RPercival (Sep 21, 2011)

Great info. I'm not changing a thing. Thanks.


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