thanks that helps alot,system i have now can be heard at highway speeds fine without distorting the sound but bass is very limited. how much mat do i use? is more better? thanks mort
Enough to cover the inside area where the speakers are is enough. You can do two layers, but only expect it to clean up the sound. The bass will always be limited. It's a function of open air speakers. Bass is air vibration and is non-directional. Since you don't have a cabin like a car, your air space is the world. For that reason, I wouldn't get my hopes up about the bass, unless you start adding subs and stuff, but even then, it will be minimal. Too much air to move.