The Black Box is a Low Frequency Resonator Array that works in conjunction with the Subwoofers, Atmospheres and FEQ X4 to solve bass node issues.
Tom - I've got 10 treated magnetic mats on each component. 5 on the top (if possible) and 5 on the bottom. I have a power strip with 4 High Fidelity MC-0.5s plugged-in that has 5 mats under it which are folded-over to create a 10 layer bundle. I really don't know what the "limit" is when things start changing for the worse.
Removing the RF/EMI absorbers from my system has made a big difference. I think they were messing-up the uniformity of the magnetic field that I've been trying to create. Previously, they only improved the sound because they helped remove "stray" RF/EMI which is all over the place due to the electromagnets being used in the transformers. But when you make a consistent magnetic field around your equipment it really does help the sound.
I let my current configuration of graphene oxide painted on alternate facing magnetic mats sit undisturbed for about 2 weeks. I listened for just over 2 hours last night. I didn't think my system could go farther in this regard but each musical image is rounder, smoother yet more dynamic. The soundstage is not more precise but is wider and deeper. I hear vocalists moving slightly closer to mics and then hear then move back. I hear slight tones coming-off the body of guitars and pianos. Its all kind of spooky but real.
I can't hardly believe it so I keep asking myself: what is going on? All I can conclude is the magnetic mats when stacked and painted with graphene oxide create a uniform and consistent magnetic field through the component. This magnetic field stabilizes over time and its natural "spinning effect" stabilizes not only the signal flow but the circuits themselves. Subjectively, I guess it really doesn't matter why the sound is improving - all that matters is: it is.