When to double wall?

[dopey 0]

I have a 15" Loaded BTL that is in 4cubes.

The box is .75 MDF. I will rebuild the box, should I doublewall anything other than the front baffle?

I will probably resin the inside of the box, as well as brace it at several places.

[ford302redneck 15]

There is no such thing as to much bracing. Hence thats what double baffling is, basicly.

Is it sometimes needed, no.

Its your call, and if u think itll flex. And if it does, just add braces until it stops.

[///M5 2,833]

There can be too much bracing for SPL, but if your goal is an unaltered response the thicker and more braced the better.

[tejcurrent 13]

I had too little bracing on my btl and had a problem, doubled the faceplate and it resolved the issue. I wouldn't see a need to double the whole thing as long as there's some bracing.

[dopey 0]

I'm not noticing any problems, just don't feel that a 75lb sub can be held as tightly with .75mdf as it could with 1.5 or 2.25 mdf.

What sorta problems did you have Tej?

[tejcurrent 13]

The box flexing. If you check the BTL 18 review I believe I have a pic in there of the sub and port facing rear-ward. I had a problem with the box flexing A LOT and the rubber gasket thing that should be sealed tight would actually work its way out from behind the sub. That large piece (about 48wx20h) had a lot of movement, and if you look at the left side of the sub in the picture you can see where it came out from under. There was nothing wrong with the size of the whole, too big or too small, I checked that 3-4 times, it would just come out after really pounding the sub for a bit. It flexed because of lack of bracing. Adding a 2nd layer and some decent braces to the new boxes took care of the problem.

[ford302redneck 15]

There can be too much bracing for SPL, but if your goal is an unaltered response the thicker and more braced the better.

Yes sir you are right. Some cars like boxes that flex.

But honestly, Id much rather not have my box flex, than have a couple extra db's... that I will barely notice.