My sub rattles the headliner at certain frequencies. Seems there are 2 options. One is to jam something in there where it meets the back window to separate the rattling surfaces or somehow get them to attach to each other. Any advice?

 

what's causing the rattle? is it the vibration from your subwoofer? if so, is it because your subwoofer is not bolted down? i'd make sure it is bolted down. in case of an accident, it would hit someone in the car.

 

The sub is not going anywhere. It is tucked behind the back seats. The bass is rattling the headliner.

 

If there is room, a little piece of Dynamat in between the rattling parts should do the trick. You can remove some of the silver layer of the Dynamat to make it work like double-sided tape - you won't hear another sound.

 

Didn't think of that. Maybe this is a dumb question but where do you get Dynamat? I've never used it.

 

Most car stereo installation outfits should have it. It may be available at automotive specialty stores as well. It's great stuff for stopping rattles anywhere in the car.