Subwoofer Project Dual 15" Eminator

To continue the speakers I've been building for our TV room (Home Theater, see other threads I've started) I recently built a dual 15" subwoofer cabinet, it's very large and will sit in the corner of the room which is currently empty and behind an end table. Got the wife's approval after some convincing =)

The enclosure

I built the enclosure to be 9.5 cubic feet minus ports, subs and bracing it's closer to 9.0. I also made the baffle removable so I can easily repurpose the enclosure for virtually whatever I want, even the ports and terminals are attached to the baffle so once it comes off any of many different configurations of speakers and ports can be used. It is built out of 3/4" maple plywood and heavily braced with 1/2" pine plywood internally. I think at some point I'll put a long excursion 18" in this as 9 cubit feel works very well.

Outside dims are 48" tall, 24" wide and 18" deep.

Once the front baffle is bolted on it is essentially 1.5" thick. I didn't have to use any sealing mechanism between the baffle and the enclosure, everything was flat and tight and once bolted up is completely air tight. Front baffle is secured with M8x1.25 t-nuts and m8 flat head cap screws.

The vertical corners feature a 1" roundover, visually it is the same as the PS2 speakers and center channel I already built. Stain is black Varathane with Minwax rattle can semigloss polyeurethane. The feet are large 1.5" rubber from Amazon. The ports are really nice 3" flare ports from Parts Express on clearance for only $4 each.

I need to DATS the enclosure to be sure my port tuning is where I want it to be, but I calculated it to be 25hz, but these flare ports are tricky to get right as the length is arbitrary once you include the flared section.

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Subwoofers

I recently came across Eminence's website where they are clearing out their "Eminator" subwoofer line, I picked up 4 15" for $34 each..shipped! Can't beat that price, they have inventory of 10 and 12" too, for the money they are really nice subs, used to sell for $100 each, stamped steel frame but reasonably sized motor, voice coil and decent xmax too. They are also very efficient at 94db each.

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Overall Cost

This subwoofer cost me well under $200 to build, $68 for the subwoofers and $75 for the plywood.

Amplification

I'll be running this subwoofer off an Adcom GFA-555 (about 350w/channel) and out of the LFE output on my Denon AVR-X4200W reciever which also has Audyssey XT32 in room equalization

As you can see in room response is flat to 20hz, it modeled well to 30. And that is with no EQ.

I think it is easily hitting 110-115db in room but I don't have a mic that reads that high, it easily hits 100db with a few watts and gets MUCH louder than that still.

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Finished product

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And compared to my 4 year old son =)

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Hope you enjoy the project!


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