Whenever i have a song that has a high point in the bass it rattles on the rear passenger side. It doesn't happen every time, but very frequently and gets annoying. Nothing looks loose at all where the speakers are in the rear of the car but I was wondering if anyone could guess what might be causing the rattling (sp?) sound. It's not like i have the volume that high, it's usually around 10-12 and my bass, treble, and sub are all at +6.

 

Play the same song again at the same loudness, go where it rattles, and listen for stuff rattling.

 

In the trunk under the rear deck there are some holes. Put some time of foam or cushion in them to put pressure on the rear deck. I have seen a few new civics that have bad rattle from just the stock stereo system but that fix ussually takes car of it and it cant be seen.