2 subs up front, 2 behind the couch?

[derekwwww]

Ok heres the situation.... I currently have a 1000W parts express plate amp wired at 8 ohms running 2 12" subs, each in their own enclosure. I will be adding two subs of the same kind to my system and will then be running the amp at 4 ohms giving me hopefully the extra bass i'm looking for. My question is on the placement of these two subs I will be adding. The two I am using now are up at the front of the room, one at each side. I was thinking of putting these two subs I am adding in a box right behind the couch. Will this sound good, or will there be cancelation in the bass since the rear subs are so close as compared to the ones up front? I would make the two new subs with the same internal volume as the fronts. I plan to someday make large new ported boxes to put two subs in a tower type design on each side up front, but until I get the time to do that I would build small sealed boxes. Any other ideas of placement or other things is appreciated! Thanks

 

[Buckeyefan 1]

I need more cowbell, I mean-more power

Ok heres the situation.... I currently have a 1000W parts express plate amp wired at 8 ohms running 2 12" subs, each in their own enclosure. I will be adding two subs of the same kind to my system and will then be running the amp at 4 ohms giving me hopefully the extra bass i'm looking for. My question is on the placement of these two subs I will be adding. The two I am using now are up at the front of the room, one at each side. I was thinking of putting these two subs I am adding in a box right behind the couch. Will this sound good, or will there be cancelation in the bass since the rear subs are so close as compared to the ones up front? I would make the two new subs with the same internal volume as the fronts. I plan to someday make large new ported boxes to put two subs in a tower type design on each side up front, but until I get the time to do that I would build small sealed boxes. Any other ideas of placement or other things is appreciated! Thanks

That's a lot of subs from one plate amp. Is this plate amp class A/B or D? If your enclosures are sealed, I don't think your issue is lack of drivers, but lack of power and cancellation. Two 12" drivers in sealed enclosures should each have their own 1000 watt plate amps. You need close to triple the power in a sealed box to equal the output of a vented enclosure. Sealed enclosures usually sound better, and eliminate a lot of muddy bass, but they are not near as efficient for producing home theater bass (you know, that U571 depth charge bass).

To answer your other question, you most definitely face cancellation issues with so many subs. You would need to eq each of them to produce a different frequency range to avoid cancellation, or at minimum, phase out two of them. I would limit the room to two subs, and stack them each with their own plate amps. I would also experiment with venting those subs. It sounds like you know just enough to be dangerous about HT bass. Post some pictures if you get a chance!

 

[derekwwww]

The plate amp is Class G. As it is currently, the subs will be used about 90% music 10% movies. Once I have time to figure out all the bracing and the time to build the boxes I will build some ported boxes, but for now I think I will just make small sealed boxes. Or is there anywhere on the net the will give you specs on bracing a certain volume box? I would just use WinISD to figure out the volume to use.

 

[mtrycrafts]

You need close to triple the power in a sealed box to equal the output of a vented enclosure. !

Are you saying that seald box designs defacto 5 dB less sensitive than other designs?