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Discussion Starter #1 (Edited)
Hello, I'm looking for some input on redoing a CSS Quartet 12 kit: http://www.creativesound.ca/pdf/Quartet12B_Subwoofer_Kit.pdf.

Back story. A couple years ago I got the kit from CSS. It includes a Trio 12 driver and 2 APR 12 passive resonators. The kit is meant to go into a 20" cube. It was my first build and it went alright, but due to time/money constraints I never got around to finishing it the way I wanted. It sounds fine, but it ain't pretty. Now that I have the time and money (and a little more skill) I would like to make a new box from scratch rather than trying to make a silk purse out of a sow's ear, as they say.

Here is a diagram of the home theater area which recently underwent a bit of a transformation. Re-arranged the layout, new seating, new AVR, new Axiom speakers, wall mounted the TV. The last piece of the puzzle is redoing the sub.






You can see the existing sub build in all it's glory. It currently lives in front of the door on the right.

One of the possible designs I've thought of to help the wife acceptance factor is to make a taller, but more slender tower rather than a big cube. Front facing driver with PR above and below it on the front face. I emailed Bob at CSS to ask his opinion and he said it has been done, but some people don't care for it and to check these forums for more feed back. So here I am. I haven't been able to find anything one way or another.

Couple questions...

Will the PRs still work properly in this configuration since they are no longer opposed?
Will there be any stability issues with it being taller?
Will it sound worse?

I'd appreciate any and all insights into this. Thank you in advance.

If it's not feasible I still plan on redoing the box, but this time flush mounting the speakers and doing something slightly more artistic/aesthetic.
 

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Why not. Don't think you have to worry about the PR's being 180 degrees out of phase because the cabinet has a time delay. Just make them very heavy and consider a plinth or base at the bottom. Like concrete or concrete board or something like that.
 

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Discussion Starter #4
Thanks for the replies thus far.

Alright, that kind of eliminates the first obstacle. The next is actually designing the thing.

I plan on using Baltic birch plywood rather than MDF. I used Baltic birch for the current cube and was happy with it, though it did chip a bit when routing. I blame the bit for that though.

I plan on using 3/4" for the box and then 5/8" for the flush mount cladding on the front. I'm sure I can come up with something to use for the plinth.

For the speaker grills I might try to ape the design of the axioms and use magnets to affix just to keep the look consistent with the other
speakers.

For the finish I plan on using a walnut veneer and a dark stain.
 

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Discussion Starter #6
What if the internal volume is a bit larger? Say 110ish instead of the 92 of the recommended cube?

Playing around with some drawings and the enclosure calculator I was thinking 48" tall, 16" wide, and 14" depth I get 110ish.

If I cut it down to the minimums to allow the drivers and amp to just fit (44" tall, 15" wide, 14" deep) I can hit 92.
 

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Discussion Starter #9
I suppose I could eat up more of the interior space with bracing and bottom weight.

I can also probably reduce the depth since I think the PRs are a lot shallower than the driver itself. The amp box could line up with one of the PRs rather than directly behind the driver.

I'll keep playing with it and see if I can get it nailed down at 92 liters net.

By the way, is there any decent software that will let me play around with box shape graphically?

I'm still really new at this. I've researched a lot, but still pretty clueless.

Thanks again for all the help. Really appreciate it.
 

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Discussion Starter #13
So I'm using the enclosure calculator and sketch up to nail down the design and I'm pretty close.

However, I have one unknown variable, and that's the volume of driver parameter. The difference between 0.1 and 0.2 cubic feet has a pretty substantial impact on the total internal volume.

I've looked, but have been unable to find the volume of the TRIO12 or the APR12. So I'm guesstimating 0.1 x 3.

There is also the question of the built in SPA500 amp, which I would guess takes up more volume than the driver itself. I can't recall if it is completely sealed or not, so I can't just assume that it's taking up the full 12"x12"x6" of space. Would it be fair to include it as an additional driver?





I'll put up a sketch up image shortly.
 

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Discussion Starter #14


As you can see it's a little tight in there for bracing. I was originally using a single brace going down the center with 6 cut outs in a 2x3 grid. This likely wouldn't work at the bottom due to the closeness of the bottom PR to the amp box. Therefore, I'm thinking of doing a T style brace that would occupy the top 2/3rds. The actual design of the brace will depend on how much volume I have left to fill up once I know what the driver, PRs, and amp will take up.

Either way it will be very close to 92 liters.

Here is the sketchup file in case anyone wants to look at it. subwoofer.skp
 

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Discussion Starter #17
Thanks. Fired off an email to Bob. I'll start thinking about the plinth and ways to bottom load it for weight.

How does Axiom keep their towers weighted low and stable without a base?



That Bracing looks pretty good. I was thinking something far more basic. I don't suppose you recorded any sizing data so I could see what the volume is? Otherwise I'll get out the digital measuring tape.



I'll sketch up what I was thinking of. See what you think.
 

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Refined it a bit. Designed the braces 3/4" thick and 2" wide (mostly). You can reduce that to 1/2" thick and 1.5" wide. And, yes, that will take some craftmanship and tools. Maybe some rounding.
 

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