Anything you can put between spikes and carpet?

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

Hockey pucks work great. I've never seen a spike go into them.

I use Timlub's method. And as the spikes are adjustable, I rock the speakers to figure which spikes I need to adjust to get them all seated firmly. I also use a level to set speakers.

The other thing I did, just last night, was to adjust the way I had the spikes set up. I guess since I bought them last year, I had the rear spikes significantly lower than the front ones to angle drivers back. This had been a sonic benefit with every other pair of speakers I've owned, especially the ones I had just prior to these, Spendor S8es. By accident, I was kneeling on my own listening chair with my head elevated above where it would be listening, and I noticed that the soundstage was much more coherent, forward, and three dimensional. Just to see what would happen I tipped the speakers onto their sides and adjusted the spike - front and back - to a uniform 2 1/8". Back in my chair with the adjusted spikes the soundstage coherence I'd heard while kneeling was still there and on the whole much improved. We'll call that a good thing found completely by accident. Still have to work on that bass though.

I use concrete stepping stones. They come in 12" and 16" sizes. And are cheap. I paid $1.39 ea. for my 12 inchers from Home Depot...