nothing will stop violant vibration from a subwoofer. not even dynamat. shit i can sit on my trunk and it will still vibrate. once again...cheap fix. and you cant tell me it dosnt work. its ben tried and tru. probly not good for every aplication but it worked for me. im not sayin everyone go out and do this instead of dynamat. of corse it no replacement for dnamat but its another option to get the rattels that dynamat didnt because of accessibility issues. so quit bein such a nay-sayer dalton