Anything you can put between spikes and carpet?

Thanks for your response. ZD, that's actually not the case. The spikes are very slim and adjustable. I've got them set up that the total of the brass footers (about 1") and the spikes is 2 1/8 inches long. I like Photon's idea as a starting point: simple, cheap, and non-invasive to carpet and floors. I may start by trying that. I am concerned that with the stone not coupled to the floor that it might induce resonances, but I suppose if I get a heavy enough piece of stone...

Great responses, thanks. Anyone else?

I use plywood on top of wall-to-wall carpet.
If speakers are heavy enough, it will work fine.
Of course, if you're a purist (and own the carpet)
you can cut out some carpet squares so your speakers can roam free!

I use standard spikes on carpet, Measure very carefully for perfect placement. Once I get placement just right, I stand on the base of my stand and push the spikes through the carpet

"I use standard spikes on carpet, Measure very carefully for perfect placement. Once I get placement just right, I stand on the base of my stand and push the spikes through the carpet."

I don't know if this is the OP's exact problem, but in my case, when I had speakers that were spiked, they didn't couple with the concrete floor underneath the carpet with the greatest solidity because the floor wasn't perfectly level. In homes with a poured slab, builders know most floors will end up with carpet and only take the time to float the concrete surface well in the areas that are going to get tile (kitchen and bath areas.) The living areas get a less well finished and level surface in many cases. I would have to move the speakers around in small increments to get an area where the speaker spikes all coupled securely. Having to move the speaker around like that isn't the optimal way to do it of course.

Adona makes some long sharp cones to go through the layers of padding and carpet.