I appreciate your interest in the acoustic treatment in my home theater.Is it muddy sound or just low volume?
If it's low volume
Another thing to consider is that Audyssey may have reduced the level of your center speaker compared to the other speakers in your system. Wayne's point about running Audyssey from just one listening position and moving the mic only slightly has some merit. I have an older Denon 4311ci and I do find the center channel's volume is low after running Audyssey. If I break out my SPL meter my fronts tend to be in and around 75dB and my center is 73dB from my main seating position. Going around the speakers and bumping up/down the channel levels makes a huge difference.
Thanks for your interest in my garbled vocal sound problem from my center speaker. I'm very confident the issue is not low volume. In fact, increasing the volume results in more distortion. However, once this issue is resolved, I will use my RadioShack SPL meter to verify the center channel level is the same as the other channels.
If it's muddy sound:
The 2D graphs don't take in to account the time domain, ie: reverberation or transient decay time (RT60). Looking at the pictures of the room there is a lot of absorbers on your front wall but it's hard to tell how thick they are. So I have lots of questions.
How thick are the absorbers and what material are they made of?
Do you also have them on the first reflection points on your side walls?
What other room treatments do you have?
Is your room in your basement?
Do you have a subfloor with insulation or is it carpet with underpad over concrete?
Are your walls stuffed with insulation from floor to ceiling?
What I'm thinking is that your RT60 over the frequency spectrum may be uneven. High at some frequencies and low at others. You might also have reflected sound reaching your ears from first or second reflection points (but not at all frequencies) smearing the sound. If you do a waterfall graph in REW it will give you a better understanding.
It is located on the second floor of our home. The walls and ceiling are 5/8" drywall, and the cavities between the studs are filled with fiberglass. There are no windows, and I had the original hollow-core doors replaced with solid-core doors with weather tight seals. The wooden floor is covered with extra thick wall to wall carpet and a thick carpet pad.
All of the panels are made by GIK Acoustics; they don't make public the exact material they use in their products, but I wouldn't be surprised if it is similar to Owens Corning 703. Other than the corner bass traps, each panel is 2" thick and custom framed with wood trim. By design, the wood trim moves each panel an additional 2" from the wall on which it is mounted (thus extending the absorption to lower frequencies). If you look at the independent test data on the GIK website, you will see the absorption of these panels is relatively uniform from about 2kHz and up.
Working closely with the folks at GIK, I have, on the front wall, 5 of the GIK panels. In the corners of the front of the room, there are floor-to-ceiling GIK Tri-Trap bass absorbers.
Before I removed them a few days ago, there was a panel on both of the side walls and the ceiling, between the speakers and the PLP. As you know, those panels were primarily for absorbing the first reflections from the speakers and the walls.
Across the back wall were 3 panels of the GIK panels that were framed with wood trim to move them 10" away from the wall and thereby increase their bass absorption.
I was also concerned that my acoustic panels may have resulted in the excessive absorption of the high frequency range of the audio. So, I have removed all of the panels, other than those on the front wall. Unfortunately, there was no impact on the high frequency roll off or the distorted vocal reproduction.
Please let me know if you have further questions about the acoustic treatment of my room; I find the subject fascinating!