Have a look at Hsu and SVS. Well, I suppose that might be difficult, with them lacking in B&M stores, but if you can find someone to audition them for you that might help. I spent a long time shopping for subs before I got mine (which I now believe is nothing special, but it's certainly not horrid and boomy). I know what you're talking about with the muddy. Keep looking...

I am the Doctor, and THIS... is my SPOON!