Get to the point Don and quit rambling! OK-Even though I have sound treatments at first order reflections, I thought I would try placement of my foam sound treatments directly to the back of my ribbons. I cut approx. 2 1/2 inch strips and placed them on the cloth material on the back. The cloth used on the Plat 4's and the foam soundproofing held together without even having to tape. Each strip was 12 inches long, therefore very little weight.
I sat down for a listen. I could not believe my ears. My vocals had never sounded better. Clear, precise, much more distinct and to my surprise sounded much louder. I immediately pulled out my sound meter to check the DB readings. Even though I would have sworn a several DB increase, the levels all around the 5 speakers were the same. I simply could not believe it!
Then I popped in my reference DVD, the Eagles Farewell One, Live from Melbourne. Wow, the vocals had never sounded better. However, because of their perceived increase in loudness, I dropped the DB level by 2 db's in reference to the mains and surrounds. In fact, when Terri heard the DVD playing from another part of the house, she walked in to listen, not knowing what I had done. After she sat down during a listen to "Cloudy Days", she said the DVD sounded different. I asked her what she meant and she said more pure. I asked better or worse. She said definetely better! The vocals were more "clear" to quote.
I don't know how this will work on mains pushed up close to a wall. However, very little, if any cost to try. You just may be surprised by the results. May try painters tape to hold soundproofing in place in the event the soundproofing material does not hold on it's own.