Finished my first-ever sub box today...

well done, looks good

ok so i have got just one question, and this my just be me being really dumb and missing somethign, but if you look at the back of the sub you will notice there are walls all the way around it, that are sealed with liquid nail and what not. Now it appreas to me that the space that is contained by thoes walls and the piece of plexi is prety small. SO my quesiton is, is there even enough air in that box to fulfill the subs minium requirements.

I really hope i am wrong on this one cus i love that box and i hope it will still work as good as it looks(especially for a first time)

Don't worry, the box is pretty close to EXACTLY what is required. The box is supposed to be 1.25 (2160 inches) cubic feet net volume (2160 inches) , 1.34 cubic feet gross volume (2315 inches).

The INTERIOR dimensions for my box are a width of 16.25 inches, a height of 12.5 inches, a bottom of 14.25 inches deep, and a top of 8.5 inches deep.

So, the volume is equal to (1/2 * 5.75 * 12.5 * 16.25) + (8.5 * 12.5 * 16.25) = 584 + 1728 = 2312 gross inches.

So, technically my box is a TINY bit too small, but I can't see that hurting things. What's three inches going to hurt? I have hooked it up to check it out, and it sounds awesome.

For answers about polyfill. Mixed reactions and lack of proof one way or the other make me hesistant to adopt the addition of free polyfill as a viable means by which to change sound dynamics.
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If you check into actual writing on the topic you'll find that there is "proof" on the subject actually. It's not one of those things that people do and pass off as "belief".

As the gentleman has stated himself, his box may be a bit small in demension thus polyfill can help extend the bass lower with some fill.

Epoxy impregnated? No, just polyfill, simple everyday polyfil which doesn't reduce box "size".

TT

i think the box as a whole looks big wnough but it seems liek there is a box with in the box that sourounds the back of the acutaull woofer and has the plexi as one of the smaller walls, but hey you built it so if you say so man i totally belive you

Enjoy the set up

Originally posted by SilverGrey330
i think the box as a whole looks big wnough but it seems liek there is a box with in the box that sourounds the back of the acutaull woofer and has the plexi as one of the smaller walls, but hey you built it so if you say so man i totally belive you

Enjoy the set up

OK, I see what you might be seeing. Here's how I did the back... it is kind of a box within a box. I wanted to use plexi so I could see the W7, but I also wanted to make sure the back is strong enough that the W7 won't blow it out over time.

The back is essentially a 3-layer sandwich. The first layer is a 1 ft. square, 1/2" thick piece of plexi glass TIGHTLY framed inside a 1/2" thick piece of MDF.

Then there is a piece of 3/4" thick MDF with a 9" square hole cut out in the center. The first layer is bonded to that. with liquid nails. The plexi glass is bonded to both pieces with clear silicone caulk and several 1" screws.

Finally, there is another layer exactly like the first one with a sheet of plexi glass in it, also bonded with liquid nails.

So, the back piece has a total thickness of 1 3/4". In the center, for the viewing panel, there is 1/2" of plexi glass, 3/4" of air, and another 1/2" of plexi glass. The whole piece is very strongly bonded and tightly sealed. The ruggedness of the piece was just to ensure that the W7 wouldn't in any way damage the back panel. The whole box was designed with this in mind, and I assure you the total volume is within 3 inches of what the specs call for.

Here's a couple of pictures of the back panel assembly to help show what I'm talking about.

Oh, and I didn't use any poly fill because to me, with this setup, I'd prefer to possibly sacrifice a LITTLE sound quality for the asthetics I was looking for.

another

last one

did you take the displacement of the sub into consideration when measuring the cuft3?

The displacement of the sub is usually something laughable like .05 cubic feet. It's listed in spec sheets.

Yes, I did take the sub's displacement into account. That's why I mentioned the GROSS volume of the box. The sub itself displaces .09 Cubic feet.

The box requires 1.25 Cubic Feet net of the sub. Adding the .09 Cubic feet that the sub displaces brings it up to a gross requiremenrt of 1.34 Cubic Feet My box is almost exactly 1.34 Cubic feet.