I just picked up a Mojo marshall style over sized 2x12 with a closed back and it is a little too resonant for me. It is a good sounding cab, but I am playing hard rock so I am looking at adding some damping to the cab. What is the best thing to use and how much should I do? All sides? A couple? I don't know a whole lot about cabs so any help you could give me would be really appreciated.