Anything you can put between spikes and carpet?

I've been playing around with my speaker positioning and a recurring issue that I've never quite been able to satisfactorily resolve came up again. While my speakers - Verity Fidelios - have pretty long adjustable spikes on heavy brass footers, I never feel like they're making especially good contact with the subfloor under the carpet and pad. I think I could possibly tighten up my bass response with a more solid contact. Is there anything that I could put the speakers on that would give them a more solid coupling for bass purposes? I was thinking of some heavy MDF squares, or even Corian, but then of course the board is not coupled to the floor. Any thoughts?
I have a thick granite slab under my speakers, and it made a good difference, because the speakers were more stable. I also use Herbie audio's Extra Thick Hush Puckies between the spikes and the granite.
I had to deal to deal with the same issue. My Tidals don't have spikes but the footers need to couple to something solid. I ended up being very happy with squares of granite (see photos in my system description.) The bass tightened up very nicely compared to lighter weight limestone tiles I'd used before that. The polished surface of the granite is a flatter plane than the surface of most concrete floors, no problem with uneven contact. As to worries about not being coupled to the floor compromising sound, one just has to try it and see I suppose. I don't see how the coupled mass of heavy speaker and stone slab is going to be making any movement of sufficient amplitude to diminish performance though. The experiment isn't particularly expensive, a stone supplier/kitchen remodeller only charged me $100 for two good sized slabs with polished edges. After replacing the carpet in our home with a floating strand bamboo floor, the speakers sound just as good on the floating floor as they did on stone slabs. We did put down a high quality acoustic foam sound transmission attenuating underlayment.
It sounds like the feet on your speakers are too fat to cut through your thick carpet and bight into the wood floor underneath. If that's the case, thin spikes should solve the problem. If you call The Cable Company and tell them what you need, they should have it right in stock.
Ok so I almost hate to bring this up but is it better to try and couple the speaker to suspended wood floor via sharp spikes or isolate it via pads made of concrete, tile, or stone? Thoughts"
I've had this issue before..just enlarge the hole where the spike is with a leather punch or won't see if you move the speakers later. This is more stable than putting a heavy slab on the carpet
I have my Tonians on a 1 1/2" maple butcher block with metal discs under the spikes. I used to have some flagstone under the butcher blocks and tried many variations with these three elements and ended up without the flagstone, then without the discs, and then with just two per speaker and then under all the spikes, all along with experimenting with speaker cabling.

It took awhile to get what I wanted which made me very aware that even the slightest change alters the sound in a significant way.

Heed all advice but in the end, trust your ears.

All the best,
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.
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...
Thanks. the only big difference is, I no longer have the Spendors - though they were a great speaker. I had an opportunity last summer to pick up a pair of Verity Fidelio Encores and took the plunge.