does the shape of a sub box matter? I know the critical factor is interior volume of the box - but does shape matter? I'm redoing things, and I'm thinking about a setup that would require sub box that is more or less triangular in shape.

I'm not an audiophile, and I'm not running high end gear by any means... but I don't want things to sound like crap either.

 

Hey Jackson, I'm on MAJOR system #3 and have built a fair amount of boxes. Volume is the key factory, but waves inside the boxes can mess stuff up as well. What I would do is make sure you're solid on the volume calculations, and then sound deaden the inside of the box to kill those waves. Any pics of your ideas? I've got a monstrous box for a backend that is an amp/electronics rack, a toolbox, and a subbox all consisting of MDF and fiberglass. Didn't turn out quite as clean as I hoped, but it's functional. PS - did you notice driving with your TJM felt a lot different? Just put mine on today and it just feels odd.

 

I have a current setup that includes:
- a box for my amp, distribution block, and relays (for rooftop lights)
- a 10" sub
- 3 drawers for storage
- a "false floor over the whole thing



It all works pretty well, and does just exactly what I wanted when I built it. I keep my spare tire on top of it all, and everything is ok. But it takes up A LOT of my cargo space. I'm thinking about redoing things... basically removing most of the storage and moving the spare tire under the false floor. Something more like this (not to scale, just a quick mock-up):





As for the TJM... I didn't really notice anything. If I really thought about it, the front seemed to ride better (not so stiff/bouncy) because of the extra weight. That may very well have been psychological though.

 

I really like that design, should give you a surface that you can set some "junk" on top of. Since the sub box portion is a trapezoid type shape you have nothing to worry about, but still fill it with polyester pillow stuffing to kill nuances in the box. You keeping the same sub? It could be difficult getting a good seal with the cuts at those angles you have, but you're wood skills are probably pretty solid by the looks of the old box.

 

I'll DEFINITELY fill the box with poly... that's a no brainer.

As for the seals... I can mitre the edges so they fit pretty well flush with each other, making the angles a non-issue. Just to be safe though, I'll use some wood filler/glue along those seams.

And yes - keeping the same sub. It's nothign fancy, but works well enough for me.

 

Is this a sealed box?

If this sub is in a sealed enclosure, then the shape really doesn't make any difference. If not then the shape is very very important, if you want to learn a lot more, "The Loudspeaker Design Cookbook" is a great read.

As a general rule I have always halfed the min/max air volumes the speaker asked for in a sealed enclosure. The larger the volume used the deeper, boomier and less responsive the speaker is. The smaller the volume you will get a quicker response and more punchy bass it really depends on your music taste. This is why I've always just halfed the numbers and went for a compromise, and has always worked well. I've built about a few boxes, seal it up nice, think air tight, caulking is your friend.

 

yes, it'll be a sealed box. I had always been told to build to the exact volume specs of the sub for best performance (granted, "best" is relative)... I like the idea of a tighter, more responsive sub, especially if it means a smaller box. That's the best of both worlds for me.

 

Then any shape is fine. Just do the math and make sure the enclosure is the right size for what you want and stick closer to between the half and the min volume air size. This will give you punchier, more lively bass. This will probably be very small, and give you more space for the rest of your box. Since a 10'' speaker will probalby only need between 1-2 cubic ft of air space which is tiny. As before just seal that puppy air tight, 0 air loss means tighter better bass.

 

I built some subwooferboxes that fit over my rear wheel wells that have all kinds of shapes to it. The advantage to weird shape boxes is that you wont have many parallell surfaces, so you eliminate the possibility of standing waves. The drawback is that they are harder to build (it took me about a day pr box for me). I'll see if I can snap some pictures soon.

Edit: added pictures

 

Here is my box. The internal volume is slightly below what was specified by Kenwood, but it is filled with poly. The back is shaped to go over the wheel well and the front goes down the side of the well. Provides a nice look and is stable. There is an eye bolt on the back of the box behind the fire extinguisher, I used a nylon tie from it to the cargo net hanger to keep the box upright.