Long room sub suggestions/questions

[asiquis]

My basement room is 50 ft X 12 ft X 7'6" with short pile carpet on the floor and painted drywall on the walls and ceiling.The widescreen is a one end and the main seating area about 10 feet from the TV.
I have room in one corner for about 5 cu ft or maybe a larger unit disguised along one wall...

Looking for DIY sub suggestions with a budget of about 400-500. I did try an SVS PB12-NSD in the room before it went to the owner's home and it sounded very good. I listen to music (wide variety including pipe organ) and for home theatre. Mains are an older pair of Paradigm 9SE, Centre Paradigm CC 270, rears Paradigm Atoms, receiver Yamaha HTR- 5590. Hoping to start with a sub build and then progress to replacing the rest.

I have some questions as well:
IF I put drivers at opposite ends of a sub and wire them out of phase is that called isobarik or is it called push-pull or compound or are all these the same? Will installing drivers this way lower the efficiency by 3db?

How does one adjust the high pass filter on a plate amp such as a BASH 300 from Parts Express?

Long post, but I am new to the site,
Thanks,
Ray

[Mike P.]

Since you are located in Canada and your budget is 400 - 500 dollar range, I'd suggest the SDX15 for $259 shipped

http://www.funkywaves.net/catalog.cfm?item=sdx_15

or the Mach 5 Audio IXL-15 for $230 shipped.

http://www.mach5audio.com/product_in...bcfaf02d824f42

Both subs work well in 5 cubic feet tuned to 20hz.

Isobaric loading is when two woofers are coupled together by a short enclosure which is only long enough to prevent the two woofers from striking one another. The woofers can be mounted face to face, back to back or front to back. It is important however to have the woofers firing in phase with one another. Vas is halved and there is a 3db loss in efficiency. Isobaric is also known as push-pull, push-push, compound, and clamshell.

Changing the high pass filter on a Bash 300 is done by changing 2 resistors. A chart is provided with the various combinations.

http://www.partsexpress.com/pdf/300-750.pdf

[thxgoon]

Push pull is an arrangment where one woofer is mounted to the box with its magnet on the outside. The two are wired out of phase so that they fired into the room in phase. The idea is that it evens out distortions due to the proximity of the voice coil to the magnet.

[Owen Bartley]

Hey Ray, you're in Collingwood! How are the hills... have you lost all the snow yet?

If this is your first project, I'd probably stick with a basic sealed or ported design, unless you really want something fancy (not to say you can't build a fancy sealed or ported sub). You might want to consider that in a long, narrow room you may have to experiment with placement a bit, to find the sweet spot. Either of those drivers should do nicely in a ported enclosure to get you down nice and low, although the SDX15 has a little more excursion capability, which may get you more headroom with the right design and the right power.

[asiquis]

The lights are all on at the hills! There is much green on the ground down here on the "flats" though.
I beleive it is cold enough to make snow-- the last 24 hours or so....
I had Tom from SVS suggest a 4.5 cu ft box with a 13.5" long 4" tube using the Parts Express 12" DVC 310-88, 250 watts @ 2 metres but when I try to put it WINISD beta, it does not look at all like the graph he sent me... his graph shows usable to 16Hz (for the pipe organ low stop). I could post the graph if I knew how (tech challenged!)
Ray