I'm using a Marshall AVT50 head with a Marshall MG412 cabinet, and I find the tone kind of distant and lacking presence. The gain appears to be lacking as well. While the cabinet is brand new, and probably would benefit from being broken in, I think I could improve the tone by somehow making an 8 ohm cabinet into a 4 ohm cabinet to match the output of the head. Is there a simple way of doing this? What is the quickest and most effective way of breaking in speakers while they're still in the cabinet?