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Discussion Starter · #1 · (Edited)
I received my two CSS SDX15 from Bob a couple of weeks ago. I think that I've finally settled on a design for them. At first I was strongly contemplating a sealed design, but I think that the additional extension of an LLT better suits what I want out of this setup. The plan is for this to replace the lower section of my TV stand. Hopefully the opposed drivers will sufficiently reduce vibration for this purpose.

The enclosure is about 450 L tuned to 16 Hz, which is a little smaller than the enclosure recommended by CSS (they recommend about 240 L per driver, so 480 L). The external dimensions of the enclosure are 44" L x 34" H x 26.5" D.

Some pictures:







Any input?

Hopefully I'll get started on this sometime next week.
 

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Discussion Starter · #5 · (Edited)
Alright, I picked up all of my plywood today and have begun building. Here is the finalized design:



It's 420 L tuned to 16 Hz with a 3" x 23" slot port that is 42" long. The external dimensions are 44" (L) x 24.5" (D) x 33.5" (H).

I'll have some progress pictures up tomorrow.
 

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I dig it. Very functional as a TV stand while performing very well. Good call on that slot port. Air speed looks to stay low enough and 1st port resonance isn't too low. Sweet. Are you gonna power this one with the Crown XTI amp you already have?
 

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Discussion Starter · #8 ·
WillyD,
Yeah, I'll be using the XTI-2000 for now. It doesn't really have enough power to drive these things to their limits in this enclosure. From my modeling, it should be able to take 2500 W or so, which is about 1000 W more than I'll get to them out of the XTI-2000.

The slot port provides a lot more ability to fine tune to port area compared with round ports. I also like the way it acts as bracing.
 

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Discussion Starter · #12 ·
Thanks guys. Here's the rest of the work from the day. Built and installed the rear wall of the port. The small cut you can see is a 1/8" recess so that the quarter section of sonotube I'm using to make the curve in the port will sit flush.



 

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Wow... Looks great... is that the Birch Ply..?
I didn't realize that you were putting both drivers in the same box...
I was looking for 2 seperate boxes, single driver in each...

I was wondering how you were going to make those gradual curves... great idea with the 1/4 sonotube...

keep posting those awesome pics...
 

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Discussion Starter · #14 · (Edited)
Yeah, dual opposed drivers in the same box. I want to have as little vibration as possible for my TV.

Yeah, it's birch ply, it is called Lion King Birch 3/4" Cabinet grade. I need about 3.5 sheets of plywood for this enclosure, and at about 90 lbs per sheet for MDF there it was going to make for a finished enclosure pushing 400 lbs. I'm not entirely sure how much weight saving there will be, but a sheet of this plywood sure seems a **** of a lot lighter than a sheet of 3/4" MDF. I'd built my last two subwoofers with MDF so I figured I'd try plywood. So far the main thing I'm noticing is none of that MDF dust that gets inside and over everything when you shape MDF. That alone is almost worth the difference in cost.

Here's today's work.



Mock fitting the top of the port:

 

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Looks like a great job.

You're using magnet supports. Do the drivers touch at the back once they're installed or is there a gap?

Can you tell us a bit of the basic theory why the opposing drivers help to reduce box vibration?

brucek
 

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Can you tell us a bit of the basic theory why the opposing drivers help to reduce box vibration?

brucek
It's the Newton's third law: To every action there is an equal and opposite reaction.

http://en.wikipedia.org/wiki/Newton's_laws_of_motion

When there are two drivers, net forces are cancelled out, leaving no forces at all. That means the drivers won't transmit any vibrations to the box.

I can say that it works great! :)
 
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