Originally Posted by
Bruce Watson
This isn't the speakers. It's your room. You've probably run up against a room mode that causes a peak in the mid-bass at your major listening position. Probably coupled with rapid reflections off that wall behind the listening position (causing the muddiness), and reflections off the ceiling and side walls making it sound boxy ("small room sound").
Now that you have the speakers that show you what the room is doing, treating the room is in order. This means not just absorption, but also diffusion (especially behind your listening position [if I've interpreted the physical relationships in that room correctly] and at the first reflection points on sidewalls and ceiling (if you can)), and of course bass traps.
One quick thing to try is to move your listening position off that back wall a foot or 18" as a test. If your midbass "bloat" changes, you'll know for sure it's a room mode problem.
Probably not what you wanted to hear. But this is the way acoustics in small rooms usually plays out.
Of course you can (I really recommend it) also get an AVR with good room EQ software, anything from the Audyssey system to Dirac, ARC, etc. These systems typically EQ the frequency response of the room (as experienced at and around the listening position) for at last the bottom few octaves to full range, depending on the system and its settings.
I've been using Audyssey on my old Denon X-4000 for years, and it does an outstanding job fixing some problems I've got in my listening room. Makes that little Luna Duo center a serious joy to listen to -- perfectly flat response, clean crisp dialog. My wife loves the Duo!
Best of all worlds, treat the room, then run EQ software on top of that. The problems you're describing will be a distant memory.