So I had a pretty basic kenwood deck installed when I got my b6 a4 in January, the sound quality was so-so and it didn't have a good equalizer to adjust the tone at all. Just got an alpine built in gps deck that has an 8 band equalizer so I can finally get the most out of my symphony 2 system, and it actually sounds pretty good and has a deep bass when turned up. There is just an annoying vibrating tone when it hits heavy bass back behind the headrests in the back seat by the big speaker/amp, but when I put some pressure on the area including the speaker itself it quiets down and doesn't rattle. Does anyone have this problem as well, or has anyone had this fixed so there is no more sound? Let me know if you have a solution, thanks.

 

Not sure if anyone else has this issue, or has resolved it, but I have found out some more info for those of you who may be interested. I found this newer thread that has a similar fix, IF that is your only problem. FIX rear deck speaker rattle ONCE AND FOR ALL!!

I have also realized the whole speaker deck in the back window is vibrating a bit adding to the noise. I did the fix above which reduced the vibration noise quite a bit, but the center brake light is vibrating against the glass causing a humming sound as well as the entire deck piece itself. The only thing I could think of would be like a custom sand bag sort of thing to put some pressure on the lid to reduce or eliminate the rattling noise. Any other thoughts or ideas? Would love to get rid of this for good, I don't even have the bass up or the sound up and it still is pretty obnoxious.