My sub is shaped like the above. It sits in the passenger footwell. When I had it fitted in my Panda, it was fine because it was sitting on the floor on some carpet.
In the Clio however, it sits in a 'well' kind of thing that is only lightly carpeted. Hence, when the bass is turned up, it vibrates in the well making a horrible vibration noise.
I'm wondering what I can do to stop this. All I can think of at the moment is perhaps covering the sub in carpet... has anyone got any other ideas? Perhaps some sort of padding to go around it?