SSD-15 Dual Opposed Vertical Sub Build

I wanted to update this thread because it's nearing completion. Here's how it all started:

Concept Sketch


Sketchup Model


And here's how they turned out, not including the top:


and


and


Finally complete with butterfly granite tops.







Performance in-room, EQ'd via a MiniDSP:


Will update again when the tops are done.

Total cost for all materials and shipping, not including labor (or food or beer) was $972.84. The tops cost $11 for the boneyard slabs (see last page), and $140 for the fabrication of them, which is in process. So, we went a little over budget, but still pretty damned close to my target of $1000 all-in.

And here's the original first post:

I've decided to go forward with a dual opposed build incorporating 4x of the SSD-15 and I need your help!

I already have the subs in my possession



(thanks bosso, love that quasi-carbon fiber look)



and, with the help of petew, was thinking of the following specs on the cabs:

24"x18"x18" constructed from birch
Double-baffled with recessed drivers
2" standoff from the floor
Existing EP4000 for power
miniDSP for EQ and L/T (perhaps a bossobassis)

My living room where these will reside is roughly 18'x14'x7.5' with an unsealable large doorway and half-wall opening to the dining room, kitchen, and a short hallway to two bedrooms and an office. So, we're looking at > 4000 cubes.

I have been unable to model the drivers in this enclosure. Does anyone have the T/S specs and time to model them? If I were to sell my Captivator, I might sell the EP4000 with it, in which case I'd need to grab a new amp. I'll cross that bridge when I come to it.

We plan to build the boxes out of birch (baltic if possible), with nothing more than a single square brace with a cutout at the midpoint between drivers. The finish I'm thinking of is just duratex, or perhaps a simple matte black. I have considered a dark stain, but I think black will match better. I eventually plan to build all new LCR and surrounds, too, and it might be nice to go with a stain instead of black.

For support, we've been thinking that putting 1/4" black powder coated right angle steel along all four corners of each sub, 28" long, with countersunk screw holes for attachment, then with tapped weldments on the bottom to house adjustable feet, and simple welded plates to hold a tempered glass or granite (to match my dining room table) accent cover 2" from the top.

I've gotten a lot of inspiration from bosso and others on this design, but unfortunately round materials were not easily accessible here in ABQ. The total weight of these is expected to be around 100lbs per cab, all inclusive.

I'd really appreciate your thoughts on the box size, modeling, wattage, staining options, and steel supports/legs idea.
Edited by nube - 4/7/13 at 1:17pm

Here's a mockup that Pete came up with:



It has everything but the drivers, feet, and weldments. And, I'm pretty sure it's to scale.

Thanks, bud. I know these will do well in my system.
Yep, as Pete said, they'll be sealed. I think the internal dims are right on, with driver displacement being about .17 cubes each, and bracing only taking up another .05 cubes. Including pillows for fill, I think we're reasonably looking at the drivers "seeing" roughly about 1.5cuft each, which is exactly where they want to be for acoustic suspension to prevent exceeding xmax. Looks like we found some 3/4 Birch Imperial for around $37 per 4x8 sheet. This build is gonna take 3 sheets, and that price fits the budget. Just hope it's good wood.
This was precisely the plan, although I can't claim to have modeled it.
A single sealed SSD-15 is going to have a lot less output across its bandwidth than a Sonotube built around the same driver, but then you also have space, looks, and other factors to consider. This build is a dual-opposed system, so two drivers, one on each end of each box.
The reasons I went this route are numerous, but include the bandpass feature of the plate and floor positioning, width and length limits, the fact of the top plates operating as a sort of end table and being beautiful if using marble matched to the dining room table, availability of drivers, and my total budget of ~$1000 for the subs, but not including amp & EQ.
Thanks for the support! I don't consider it a threadjack, as we share a common vision. I think the "easy button enclosure" is a good idea, and I'll try to provide detailed cutsheets and assembly plans at some point.
Your suggestions are as good as gold. Thanks!

The assumption I'm making with Marty's potential sono enclosure is much larger size resulting in greater efficiency if sealed. I wanted to go with a smaller sealed sonotube or similar design, but the mats were hard to track down locally.

As it turns out, Dave, I had thought about that. Pete owns a successful high-end windows company, and can get tempered or normal glass in any size/shape/color needed.

I have a somewhat uneven tile floor, so creating stability was key to this design. The plan is to have weldments made at the top and the bottom end in the corners of each support leg. 1.5" pieces of 3/8 or 1/2 CRS plate will be used, and we'll drill and tap it. The bottom weldments will serve as a means to place adjustable legs into the base. On the top, these weldments will serve as a platform on which to rest the glass/marble/whatever to make the table top.

But, these weldments will have a dual purpose. They will also serve as a means to stack the enclosures, should I want to in the future. In that case, I'll just get some long stainless bolts that are slightly underside for the tapped holes, cut the ends off and grind/chamfer them. With some metal pad to disperse the weight on the ends, I'll use them as guides with which to sit one enclosure on top of another. I don't necessarily foresee doing this, and I'm uncertain how stable they'd be, but it's an option.

My first inclination is to get glass cut & beveled (it's cheap), and set it on little felt pads on the top of each enclosure's corner weldments. Perhaps later I'll try to find 17.25"x17.25"pieces of marble that match my dinner table. Or maybe I'll just go with a gorgeous, dark granite.

I'm also considering making magnetic grills for the top to keep out the desert dust and hide the drivers from curious visitors. Would that impact the bandpass function of the top plate in any way?

Today I finally picked up the wood. Pete was kind enough to place the PO for the sheets of Baltic Imperial Ply (Chinese) and let me use his Ranger to grab the stuff. Priced at just under $37 a 4x8 sheet, it fits right in my budget.



Yeah, it has some bow in it, and the birch veneer is pretty terrible, but whatever. We'll make it work. The extra is for other upcoming projects...

Took the protective cardboard the lumber store wrapped the sheets with and gave it to one of his two Goldens, Tanner.



There's a good dog! If you think this guy is defective, you should see Pete's cat...

Getting to work, the first order of business was to get all the cuts mapped out. Luckily, Pete is a master of this stuff and had it all figured out and written down in about 5 minutes. Total, for both cabinets, we're looking at using 2 sheets with not too much dropped.



We ripped all the pieces roughly to size. That Chinese glue sure does stink...glad to have Pete's dust collector & big ventilation system working to minimize our exposure.



Lastly, we sorted and labeled all the pieces with Pete's madness method, stacked and clamped them to prevent more warping, and setup the place for the jig to do the driver and bracing cutouts this weekend.



And, as you can see, Pete's a real patriot, with his American flag, framed T&A hotrod pic, Sammy Adams bar light, and BOSE shop speakers. The guy doesn't even have Led Zepp's "How The West Was Won" on his Sonos system. (Which, I should add, is a slick f'ing system for whole-house music! And the BOSE speakers don't sound half bad...for shop speakers!)

To end the evening, we enjoyed a Super IPA from New Belgium & Alpine Beer Co.



Tasty stuff!

Not bad for about an hour and a half of work. More to come this weekend.

We had another couple of hours to work on the cabs today, but not until after we smoked a take-n-bake pizza on Pete's awesome automated smoker. It was so darn good and cheap, it's gonna become a regular gathering choice. I think my decades old Weber will accept the family sized one, too.

Lots of pics because I busted out the DSLR. No more camera phones for me!

First things first, we got pretty spot on with the baffle centering.



So then we had to square up all the baffles and trim them to size.



Turned out pretty good. Oddly enough, we hit a speed bump and had to trim an extra 1/8" off one side of everything. Not sure how that happened, but oh well - it was an easy fix.

After that tiny hiccup, we got back on track and squared everything perfectly to size. We even broke out the micrometer, and everything was within ~3-5mils.



The next step was cutting dados into everything. I'd never used a dado blade before, but Pete has two. He mentioned a wobbly one which is funky, but I'm not a big fan of Parliament, so we went with the precision one with multiple shim/spacer blades. First up was the bracing dado in our short sides.



Then the dados for the baffles on each end. First cut the inner dimension of the dado



then the outer. The Chi-ply is a little warped, so this took some pressure and multiple passes, but it turned out perfect.



Then it was time to figure out a clamping strategy. We started by laying down some paper to work on. It sucks to get glue on your table saw!



The next step is fitting the pieces together. This is the length.



And this is the width. We ended up changing the bracing strategy yesterday to accommodate a fudge up on one of the routered panels, so instead of a full interior brace mating with all sides and having hole cutouts, we opted for just overlapping pieces touching two sides each. Works for me.



The dadoed corners worked out great, just as Pete had said they would.



Then came the gluing and clamping. We're using Titebond II and Pete's Bessey clamps. (Those thing's rock!) In the Albuquerque dry climate, the Titebond II is pretty much set after a couple of hours.



Yeah, it's probably overclamped, but who says you shouldn't get OCD about this stuff?



Turns out the corners worked great, and the glue fills the little voids that are present in the Chi-ply.



Then we wiped all the squeeze out and called it a night. Total finished length ends up being 23-3/8 IIRC, with about 1/32 overhang on each end to use the flush trim bit on.

Tomorrow we'll glue up the other cab and think about the final sides.