Super shoebox sub installed, rattles like no tomorrow

[Infidel]

So I finally installed my super shoebox sub this weekend. The car rattles so bad at even moderate volume levels that its all but useless. (Serves me right, being a SQ/SQL guy and buying an SPL sub, I guess). There appears to be heavy buzzing comming from the right rear quarter panel, and significant rattling from somewhere in the left rear quarter panel as well.

I've got about 10 sq ft of dynamat that I can use, but I've never installed it before, I hear it's very permanent, and I want to make the most judicious use of the stuff possible. (read, use as little as I can get away with). Since I can't imagine anyone lives with this rattling, what have you guys done to quiet things down?

What's interesting to note, if you place the sub in the spare tire well and fire it up to the hatch glass, almost all the rattles vanish. I can't imagine why the sub is firing an inch away from the quarter panel rather than into the cargo area, but I digress...

Anyway, can anyone give me some advice to cut my "trial and error" phase some?

[jbrasure]

My shoebox sub initially rattled the car just like you describe. Then I had a stereo shop install dynamat, and all is well. I can crank the subwoofer like crazy and it never rattles. Sounds fantastic!

The stereo shop put dynamat inside the spare tire well, on the right rear panel, and on the metal piece that holds the subwoofer in place.

I hope that helps.

[Rick]

Ahh yes, common problem with the super shoebox, it fires that massive woofer right towards your rear quarter panel. Here's what I did that's not so permanent, please mind I didn't have nearly adequate power going to mine.

Find a general materials shop that carries automotive carpet padding. This stuff is cheap, maybe $4 a yard and it comes in various thicknesses. It probably recycled other bits and pieces anyhow. Put it under the shoebox and line the surface that faces the rear quarter panel. The piece under it will make it a very tight fit. The other source of rattling is the box itself where it bumps in to the two screw holes that the alluminum floor piece above it screws in to. Take some small pieces of the carpet pad and use a screw driver to jamb it inbetween the box and the screw hole. This will cause the box to fit a bit too tight and you won't be able to get the plastic screws back in the front of the floor piece, but it will be good enough and I had no rattles after I did that.

Although if I were to do it all over again I'd heavily consider dynamat. I just had it in my head I wanted to do everything to it was easily removeable, and believe me it was removed before going in to the dealership when my IMA light came on. So you might take that in to consideration, though I don't think a little bit will be a huge problem.

If you want better sound from the front speakers put some sort of sound deadening material on the inside of the door panels as well. This makes an amazing difference by blockout out the sound waves created by the back of the speaker. There is no noise insulation in the doors anywhere, or much of the rest of the car for that matter.