Sound diffusion panels--do they reduce brightness?

Wow lots of good ideas. Will get working on the suggestions this weekend
I did try some other speakers with the same brightness issue. The midtones and bass are good.

Here is something you can try to determined if you have an equipment issue or the brightness is being generated by the room

Warm your system up and give a quick listen to one of your reference CDs that you are very familiar with at your regular listening position (sweat spot)

Now replay the same tracks but go into the room in back of your listening room/chairs and give another listen

If my guess is right when you go into the room in back of your listen room ... the brightness will be greatly diminished because you are not sitting in the direct reverberant field that is aggravating the problem in the main listening position

By going into the other room and listening you remove yourself from the extended/sustained ringing in your main listening room that is being caused by the long RT60 times, Echo Slap, and Comb filtering

If your system still sounds overly bright when listening from the back room ... then you have an equipment issue because you are no longer being effected by the room's anomalies when you are listening from the back room ... it is the equipment that is generating the brightness ... metal dome tweeters ... tube in the pre amp fading or poor match ... etc etc etc

If when you listen from the back room the brightness is greatly reduced then

1 I know What the problem is
2 I know What's causing the problem
3 I know Where the problem is occurring
4 I know how to fix it and your significant other will never realize the you've applied some new room acoustics

Please let us know the results of your listening tests

Get that ottoman out'a there for starters!

Davehrab wrote: By going into the other room and listening you remove yourself from the extended/sustained ringing in your main listening room that is being caused by the long RT60 times, Echo Slap, and Comb filtering...

Not true. You are still hearing all that but with a very different perspective that affects the timing of those elements and, in fact, superimposes the filtering of the transition to the other room as well as the acoustics of the other room. May be informative but it is not unbiased.

Kal

I agree with 4est. Your ottoman is leather which is a reflective surface in close proximity to the listening position.

Before treating your room you may want to take a close look at your system components. You may have one or more components bordering on lean or thin sounding.