Vibration from subs behind rear seat in double cab

So I have 2 10" subs in a box behind my rear seat. There is raam mat and the foam topper beneath it.

When the sub hits, it vibrates and distorts somewhere in the cab and sounds bad outside the cab. Inside, it sounds okay. I'm thinking it might be the plastic seat backs. Is there any fix to this or should I just remove the seat backs?

 

You should mount the boxes to the rear wall

 

How?

 

I used 1.5" self taping screws. 1 into the rear wall and 1 into the floor

 

I'd like to see pics of your setup. is your box rattling? or are you getting vibrations from the adjacent body panels/walls? my (2) 10's in a box doesnt rattle in the cab since it is wedged between the rear wall and the rear seat. I'd look for the least amount of intrusion solution before I do unnecessary drilling into your truck.

 

Let me try to shoot some video this week. It is wedged in there tight behind the back seay and I don't think the box is moving. It may be the plastic seat backs, but I'm not sure.

 

I've got vibrations on my interior plastic pieces. I've removed the rear seat storage bins, so it is just subwoofer box behind the seats. there is adequate sound deadening(raamat, and the foam stuff), but when I'm pushing the volume, there are some rattles. I just live with it, since I dont have a garage to just leave my truck in a half way state.

 

vibrations could be caused by vehicle plastics that have not been sound deadened. As someone mentioned, can be caused by seat backs, can also be caused by poor box construction (wave resonance). ie: internal bracing, thin mdf, poor sealing, can also be port noise if your box is ported.