The correct removable padding to use on top of the speakers is herbies grungebusters. Available in different thickness and diameter circles they don't mar, don't slip and bust grunge in the sound. I use a few small dots under my Crown Phono Modules with excellent results.
https://herbiesaudiolab.net/gb.htm
Well - the top stones will be damped by a large piece of cut to size, cut to fit drawer liner ...
https://www.amazon.com/EPPCO-Enterprises.../dp/B000VHXEJ6
at $12 a roll, easily installed or removed, and larger than needed, its worth trying once!
and -
it arrived this morning while we were at church! Thats ready to go!
Now I'll need to go find a source for the 18 x 24 x 1 inch or so Granite slabs!
These techniques I am sharing are proven with a friend of mine's pair of Heath AS-101s a bit north of here. He did improvements like this to the physical structure of his pair, and will also be sharing crossover updates, horn treatments, and additional treatments to the woofer and horn driver that resulted in a system that knocked my socks off when I heard it in January.
So, I found a pair of Heath AS-101s shortly afterwards, won the eBay sale and had them U-shipped here, and listened to the base systems for the last month. I added a large amount of polyfill into the cabinets (not my guru's idea) and that lowered the low frequency capability of the system. I know that, based on music I knew well through other speakers, where it rolled off on the original config of the Heaths, and the lower notes I could hear in the music afterwards. He has other approaches using a multitude of products like lambswool and such to get lower bass from the system. As well as woofer cone treatments.
Obviously, with the speakers upside and on their sides as I glue the ceramic and granite tiles to the cabinets this week, I won't be listening to them again until maybe next weekend. But these are techniques my friend did with his heaths, so I would presume if I copy his techniques on my Heaths, his sucesses would carry over to my speakers.
He did remind me of the bottom line of all this today:
"Just keep in mind that when the smoke clears on your speaker project, although the speakers will be much improved, they will not provide a "band-aid" for the rest of your system. At the same time -- they will step out of the way. As you adjust, change, or upgrade your various components ahead of the speakers, you will not be "lied to" or misdirected.
That includes everything -- Vinyl, digital, pre-amp, power amp, line level interconnects, speaker cables, type of music, 3-fingers of Scotch, etc."
Darned if thats not wise words on a project!