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Discussion Starter #1
I've started a subwoofer project and would like to document it here. My original plan was to build a dual-driver EBS which will house two TC Sounds dB-500 12's. However, I decided to build a practice box before I dive into the huge LLT. This box will house either a single dB-500, or a single Sony Xplod 12 which is my current subwoofer. The Xplod is currently in a 2 cu ft box tuned to about 20 hz. This alignment, while better than a sealed enclosure, leaves much to be desired below and around 20 Hz. The practice box has a volume of about 4.2 ft after subtracting the brace, port, and driver volumes. Two three-inch ports will tune the enclosure to about 18 Hz.
 

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As it turns out, it's a good thing I started with this practice enclosure, as my original plans for a 5 cu ft box turned into 4.2 cu ft. The pic of the front baffle should give a clue what went wrong. If it's not obvious at first, note how low the driver is sitting in the enclosure. There's 3/4-inch missing off the bottom! When I laid my design on paper and then cut the individual pieces, a miscalculation caused this mishap. I should have subtracted 3/4-inch off the sides for the panels to fit, but instead I subtracted 3/4-inch off the sides and the top of the enclosure. This made the entire front baffle 1/2-inch long all the way around the enclosure. The quickest (and cheapest) fix was to cut the front and rear baffles 3/4-inch shorter to make everything fit. Instead of bringing the ports closer to the enclosure walls, I moved the woofer closer to the bottom. Hopefully the ports will be able to work to their potential.
 

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These pictures are basic examples of how we started actually putting the panels together. Pretty self-explanatory. The only tools we had were a router, straight-edge, cordless drill, Dremel with circle cutter, and circular saw.
 

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Unfortunately I got busy with the woodwork and forgot to take pictures until a bit later. Here is a pic of one of the inner braces that will help brace the box as well as the ports.
 

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Right now the silicon sealant is drying around all of the edges and I won't be able to get back to it until Saturday. I'll be able to attach the woofer, add some wiring posts, and put on the top.

One question, though... If I were to hear rattles or change the length of my ports in the future, I would need access to the inside of the box. What do I need to do to attach the "lid" without gluing it in place? I don't want it to leak at all; I will silicon around the outside edges but will that be enough? I suppose if worst comes to worse I can lay the box on its' top (with the ports close to the floor) to help attenuate any rattles. We'll see. :D
 

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Discussion Starter #9
Does your SPL graphing include input power to Xmax and applied high pass filters for over excursion protection? The bracing needs to have a lot of material removed, the box won't work as shown, it has 3 separate chambers.
The picture doesn't show very well, but the braces don't completely separate the three chambers. They're each 11" long while dimensions themselves are closer to 21 x 24 x 28.

Does the air need "line of sight" to the rear or can it easily snake its' way through without causing any audible distress?

Edit: Yes, filters are applied and everything is modeled at Xmax.
 

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Discussion Starter #13
Got it up and running. The room's a bit messy because I'm in the process of rearranging to make room for the sub(s) (will probably end up having two of 'em).

There's definitely a difference in output when compared to the Xplod/2ft^3 box. I only wish I would've tuned it just a hair lower, closer to 17 Hz. The output is pretty amazing right around 20 Hz (and much better between 16 & 20 than the Xplod) but I won't hardly ever be using the full potential SPL of the enclosure. Dual 3" ports 22.5 inches long tuned to about 19 Hz.
 

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