First DIY Sub Array Help

[Ronscott]

I've been lurking too long, and admiring the expertise of the members here.

I'm thinking of building a sub array with four 12" or 15" down firing drivers hidden in a "bench" below a 100" wide front projection screen. I would like the bench to be about 8' long, 18" high (including legs) and about 20" deep (dimensions are flexible). Since this is my first speaker-building attempt I'm thinking of a sealed enclosure. I haven't seen any plans on the web for subs with four drivers.

My home theatre is a front projection setup in a 12' x 17' area but open on one side and part of the back to the rest of the room (total room size about 20' x 24'). The five speakers are all modest in-wall units. The room is very live, with tile floors (except for an area rug in home theatre area). My 10" sub provides little bass and no low frequency sound effects. The room acoustics are obviously pretty lousy, but the in-wall speakers sound better than they should except for the absence of bass. (I know what good sound is like-I still have a classic old pair of active Meridian M20s in another area of the house).


I would really appreciate any feedback on whether this approach is likely to work pretty well. For example, would I gain anything with 15" drivers over 12 " given the small size of my main speakers?

I have two other initial questions.

Can I simply put four drivers in one box with four times the volume required for an individual driver? Or is is more complex, like making individual chambers for each driver.

The wiring diagrams at Crutchfield show ways of combining parallel and series wiring to achieve a wide variety of desired impedience, so I'm considering driving this with a single plate amp. Is this a good choice?

I would really appreciate any suggestions. Thanks.

[ThomasW]

A couple people have made subs like this. No you don't need separate chambers, it's better to have one big box.

The legs should be 4" high.

You don't need any plans that are specific to the subwoofer, if you build it sealed. Simply make a box as large as physically possible (larger than your stated dimensions is a must). Use adequate bracing so the walls don't flex..

Unless you're planning on buying the big Adire ada plate amp, you should consider other amp options.

[Ronscott]

Thomas- My starting size is about 14 cubic feet I think-do I need more volume that this even for 10" drivers? Any recommendations on the other amp options?

[Jose_L]

Look at the DIY Sub showcase thread, lots of different designs.

From my limited experience and reading alot of diff. threads, I'd look at 4 - SoundSpliter RL-p15's ~$269ea.

http://www.soundsplinter.com/rlp15_premium_series_15_inch_DIY_subwoofer_information.html

and power them w/ 2 - EP2500 amps ~$300 ea. 750w/ch @ 4ohms.

http://www.8thstreet.com/product.asp?ProductCode=21112&Category=Power_Amplifiers&p=true

This is just a start, but also look for about a 4.5 cubic ft enclosure for each driver.

Again this is just a start, good luck.

Regards,
Jose

[ThomasW]

It's not the size of the drivers that dictates the size of the box. The Vas and other considerations dictate box size. IMO, 10"s are a bit small for real HT use....