Box resonates?

[hatedonmostly]

As most of you know, I did a blowthrough recently. Here is a picture:
http://img188.imageshack.us/img188/8196/dscf4064k.jpg

The box resonates at higher volume, and I can't pinpoint why. A few things to consider:

-The box does NOt leak air at all.
-The top, bottom, and sides are only single baffled because the subs are low power speakers, and I didn't think it'd be much of an issue. However, the sides have all been fiberglassed inside and out.
-The box does NOT flex.
-The fiberglass bottom of the box is resting right on the sheetmetal of the bed. Perhaps this is what is causing the problem?
-There is no bracing in the dead space of the box.

Or is this just normal/normal when doing a blowthrough? I don't hear it inside the car so it doesn't bother me, but it's pretty loud outside and I only have two of the four subs in and playing right now, and I'm worried about it getting worse when I add another two.

[slim2fattycake]

The reason could be that the box is on sheetmetal and the box is barely jumping or that the box needs more bracing (or mass loading). I know that my home theater box was 11 cubes and it didn't flex but had resonating panels. I put a hand on a side and it stops.

[hatedonmostly]

I can stand on the box and don't notice much of a difference and the box isn't moving or jumping, it weighs like 300 lbs. But it isn't bolted down yet, so maybe.

[Johnny Law.Lulz]

cuz your gay and you have the name layframe with a dokota that is stock. :fyi:

[hatedonmostly]

lulz and so will you soon, feg. gtfo

[Millertime1028]

Go under the truck while your bumping and push up on the bed. See if that supresses the noise. If not just try to pinpoint the noise and go from there.

[hatedonmostly]

When the bass is hitting it makes a sound just like if you hit the palm of your hand on the box. Not enough bracing? :crap:

[dappa5]

box slap

[hatedonmostly]

Against the bed?