Calamity Jane - twin, dual 12" sealed HT subs

I bought all the components from Parts Express and I cant say enough good things about their business: excellent customer service, great prices; lightning fast shipping. Here's the parts I used:

Dayton Audio RSS315HF-4 12" Reference HF Subwoofer 4 Ohm
Part # 295-464

Neutrik NL4FX Speakon SPX Series 4-Pole Cable Connector
Part # 092-190

Neutrik NL4MPR Speakon Connector 4 Pole Round Chassis Mount
Part # 092-054

Parts Express Speaker Gasketing Tape 1/8" x 1/2" x 50 ft. Roll
Part # 260-542

Behringer NU6000DSP iNUKE 6000W Lightweight Power Amplifier with DSP
Part # 248-6710

Plus miscellaneous box building stuff like glue, screws etc.

I started with two of the Dayton 12" HF drivers already. They were in a couple of downfiring cabinet subs that were Calamity and Jane's predecessors and the plate amplifiers died. I wasnt too sad because it gave me a chance to build some more subs Which, I really enjoy. My HT isnt too big and the other subs were downfiring and discrete. I wanted these to be the opposite - front firing and big. This meant they had to look appealing. And be able to back that up with some serious SPL. Obviously nothing but the Behringher Inuke6000 would suffice for a power amp. This meant running new speaker wire up to the front of my HT where before I just had signal wire to get the signal to the plate amp in my previous sub's. This meant more work but it had a dual benefit; It would locate the amp back by the AVR where I could make adjustments easier and, it would put all the audio components on the same power circuit. The latter would eliminate hum in the subwoofers which was minor but always there.

Jman - They sound pretty good. I just took my first REW measurement yesterday. I've got a lot to learn about fine tuning the processors and acoustic's etc, but with just some initial tweaking I'm pretty happy and I'm confident I can get a lot more from them. But they easily overpower my HT now so I'm shifting gears to add bass trapping. I knew they would but I refuse to turn them down

This is where I started - Home depot. I took my cut list to them, selected 1 sheet of 4x8 oak plywood and 1 sheet of 3/4" particle board. They cut them to my rough dimensions for free. Nice service.

In hindsight - I should have not got the particle board and just went with a second sheet of oak plywood.
And, I forgot about the grain direction. That realization came upon me after the first cut. Oh well. It turned out ok in the end.

Next part was easy. Fire up the CNC router :R

Here its cutting the bottom and top out of the oak plywood. And the internal braces out of the particle board

The back's have about 3 dozen, 1/8" holes and a pocket for the speakon connector. They screws are outside the gasket and hold a good seal. On the prototype I just threw the back cover on without much thought. When I put some test tones through it I couldnt believe how much air pressure they generated and leaked out the seal on the back! I knew the final version would need to have a strong seal.

The front baffle is an inch and a half thick. I made it from 2 pieces. The front piece is oak plywood, the backer is the particle board (hindsight - I should have used plywood instead of the particle board). Using two pieces made it easy to recess the drivers and to assemble it without any fasteners visible on the face. I used the CNC router to cut grooves in the particle board that the internal braces fit in to. The sides were also grooved to accept the internal braces. I was very happy I did this when it came time for assembly.

After a few hours on the CNC I had most of my parts and a big pile of scraps :laugh2:

This is a pic of the prototype with the bevel around its face. I liked the looks of it and wanted the final version to have the bevel. I moved all my parts over to my friends wood shop and started assembling the box. The back corners were beveled to. I used a brad nailer and wood glue for 75% of the fastening. The dado and groove system makes a strong joint. Everything went together very well. Barely any variation between the two boxes. Heres a bunch of pics of the assembly:

To cut the bevel on the baffle I temporarily put the front and back pieces together using the fence on the table saw to get them aligned perfectly. I clamped them together and drilled pilot holes and screwed them together. My plan was to separate the two pieces after cutting the bevel, mount the particle board face to the face of the box, then use the screw holes and glue to reassemble the two pieces exactly the same way they were when I cut the bevel. It worked. Here's the pics:

With the bevels cut, I separated the face and backer of the baffles. I did a couple test fits and then got out the Gorilla Glue. I laid the cabinet/box down on its back and glued all the edges that would attach the baffle backer. I used regular PL wood glue on the outside edges but I used Gorilla Glue on the edge of the internal braces. A little clamping bradnailing and the judicious use of screws and I had half the baffle in place. I still had to install the face of the baffle but they had to go back on the CNC router for some engraving first. I packed up my mostly completed boxes and left the woodshop and went home. I gave the inside of each box at least 2 coats of fast drying spray polyurethane. This was done to help the seal. I thought it would counteract the porosity of the wood. I don't know if it did but it was cheap, easy and with all the work goin in to this, it couldn't hurt.

Back home I started to work on the finish. If I was going to screw up, this was probably where it would happen. I didnt have a plan to finish the bevel. It was half particle board and half oak plywood. In hindsight if I would have used oak plywood instead of the particle board it would have been less difficult I think. I considered veneer but since my grain direction was, ahem, non-traditional, :whistling: it wouldnt have been easy. I considered painting just the bevel but I didnt decide on the solution for a week or two. I'm glad I didnt paint or veneer.

But with the boxes all together except for the baffle faces, I started finishing. I used MinWax polyurethane walnut satin finish. Its not the professionals choice but I'm no professional. :R

The baffle faces went back on the CNC to get their names engraved. My 18yo son helped me decide on the names. Aside from the cantankerous frontier woman of the early 1900's, Calamity and Jane are the names of two pack-a-punched guns in Call of Duty- Black Ops. It was somehow a fitting name for two prominent subwoofers :R Oh, and he told me the font had to be different to. Something to do with the X-Box game... kids :coocoo:

I glued on the baffle faces and screwed them from the inside. My method worked pretty well but a couple of more 24" clamps would have been nice. But the bevels lined up perfect. I sealed all the seams with caulk and any place there was going to be a gasket I put on at least one coat of polyurethane. In fact, every square inch of surface area of both boxes had at least 3 coats of spray on or, brushed on polyurethane. I did not want any leaks.

The seal on the back door worked great. I skipped the gasket tape on my previous subwoofers and I wasnt making that mistake again. I started putting in some acoustic denim stuffing too.

I mounted the drivers and lined the sides with more denim acoustic fill. I wired the drivers in series for an 8ohm load. If I didnt already have 2, of Dayton Audio HF drivers, I would have rather used a 12"driver with 8ohms impedance. That way I could have wired them in parallel and driven a 4 ohm load. But, with the 6000 watts RMS of the Inuke it didnt matter. I can still blow these drivers if I get carried away even wired at 8 ohms.
I lined the back door with denim and stapled it in place. I made sure to leave some room for the speak-on connector. I also later added about 15lbs of silica sand to the bottom. THis made it a little more stable. And heavy. The insides were done. I intend to measure them at some point in the future and if there is a significant difference in tone or output I'll try to adjust the amount of fill. But for now it seems fine.

I went and got some cabinet screws from Lowes. 72 screws later I had both backs on and sealed. Highly recommend cabinet screws. And the SpeakOn connector system worked great to. I didnt know this when I started but Monoprice sells custom SpeakOn cables. Its not hard at all to make them but if anyone would rather buy than make, Monoprice is there.

So, functionally they were done. I hooked them up, listened to them for awhile and they needed some EQ but they worked well and promised to work very well. But now there was no longer any way to avoid finishing that blasted bevel. By this time I had kicked myself a dozen times for using particle board instead of plywood. :foottap: I was going to have to branch out and do something I had no experience doing; vinyl. I ordered some faux carbon fiber in black I watched a few Youtube videos, read a bunch and gave it a shot. I had lots of extra in case I screwed up. I ordered a knife, squeege and some trim tape as well. Took a deep breath and got started. It wasnt too hard. The more I did it the easier it got. Pretty happy with how it turned out. I was almost done.

I had an idea I had never tried before but thought it couldnt be too hard. I wanted to highlight the name engravings somehow. A real wood worker would do an in-lay. I was under no illusion that that was beyond my skill's. I could paint? Wasnt good at that either. No, I was going to use dyed epoxy resin and just let gravity do the hard work. :R I had the resin. I ordered the dye.

I laid each subwoofer on their back and leveled them up and masked off the area. I mixed up about 60mL (way too much) and added the dye until it was shiny black. Used a syringe and carefully filled in each letter of the engraving. It flowed in nice and easy. 18hrs later - Done

Thanks for all the good info on this forum. Hope somebody can find this useful.