I hadn't heard that. The Brown Bread website even offers a comparison of Brown Bread and Dynamat and even sells Dynamat. Brown Bread gains respect with me since they post Dynamat's Technical Specifications on their website in contrast to Brown Bread. And the Specs listed on the Brown Bread site for Dynamat are exactly the same as the Specs listed on the Dynamat site. I've got no complaints about Brown Bread. My only issue is that I didn't buy enough, and couldn't sound deaden my doors. And guess what rattles in my car now? Only the doors.

Thanks.