I have braced the inside and screwed everything down, but the top of the 4th order still vibrates like crazy. It makes a horrible sound of the mdf slapping together.
I didn't glue it down because I wanted to be able to take the top of to check out the subs if there was anything wrong with them, and it was such a tight fit into the trunk of the car, there is no way its gonna come out again. The box was built to the max dimensions and it took five people to get it in.
What can I do? Is there any way I can stop the top flexing from the exterior of the box? Has anyone had this problem before?