I also have a HSU sub woofer mounted on two stages of brass footers, with a maple butcher block in between. The sub does not move as all the brass footers have machined needle points either to the maple butcher block or through the carpet to the plywood subfloor.
BTW, a good site that explains how these brass footers and maple blocks work is Mapleshade audio.
BTW, a good site that explains how these brass footers and maple blocks work is Mapleshade audio.