I've got a 2001 A4 1.8t without the bose sound system and when i turn on anything with very much bass, the whole sound just goes to crap. I'm not sure if it's because the speakers are worn out or because something in the doors are loose. Has anyone else had this problem, or is it just me?

 

Speakers are probably worn out. Also, those speakers aren't meant to handle bass, that's what a sub is for, so it's probably going to sound like crap.

 

If the speakers have a crackel-ing or "farting" like noise, they're most likely blown. A simple visual inspection will tell you if they're damaged. Remove the door panels, and speakers. Gently push the cone in/out with your fingertips around the center (dust cap). Listen for any grinding and/or binding. Look for the surrounds to be in good condition - not torn. Use a Digital Mulit-Meter DMM on the terminals for a resistive load - something like 3.2 ohms is normal - as long as it's not 0 or infinity, and similar to the other speakers, consider it good.

You didn't mention what you were listening to, or how loud...do you have any subwoofers in the system? You could get some "bass blockers", but these come with their own set of compromises...

 

Thanks. I haven't checked this post in like a week and a half. I don't have any subs in the system yet, and I listen mostly to rock. I think it's the doors that are vibrating, not the speakers, but I'm not sure. Doesn't matter that much, though. I've got Polks for the front doors and the rear deck coming in this week, along with 50 sq. feet of dynamat. I've also got a 600 watt Jensen amp lined up to power a single 10" or 12" sub, but I haven't gotten one yet. Hopefully with the new system the vibrating noises won't be as bad.