Tpg, I ask the location cause big cities can cause issues. I live near huge radio towers that create big issues in my system. Perhaps, what I am benefiting from is reducing all the noise from the towers which proves better results then the negatives of applying it. If I would move up north of here in northern minnesota (you know) I may get some of the chocking out the life, but maybe the huge towers and big city are whats chocking out life and the ers is to the rescue.
I know that I already have about 20 sheets, 8 shakti stones, 400 ferrite cores spread around my house and garage among other things. The noise floor keeps dropping and cymbals become more brassy, and natural.
If I move south on a ranch like I'm thinking, I realize I will have a flood of this stuff that I wont need.
Tbg, your focus of creating a real sound may be the right track. I think some of us, when designing are systems are actually heading down the wrong path of the sound they are trying to create. They create what may sound good to their ears, though that may not be accurate for realism of reproduction.
I use drums and cymbals in music to create a natural sound in my system as I am a drummer.
Geoff, I am not surprised by the results of placing a sheet on the table. I have heard of guys lining their room walls with a large roll of this stuff.