Homemade floor protectors -- advice needed

Here's my situation: I have hardwood floors that I want to protect from my speakers' spikes. I could use those little support disks, but they're a pain when adjusting the speaker position (they move out of position, and then I poke holes in the floor). Instead, I was thinking of placing two stone "tablets" on the floor, and then putting the speakers on top of them. There's a shop nearby that will cut the stone to my specs, and then polish the sharp edges.

My question is, what kind of stone would work best? Granite, marble, or something else? And would some small rubber "feet" on the floor-side of the stone still allow the tablet to couple with the floor to reduce resonances further?

Any insights you can share would help!
Spike those puppies to the floor. Back when I owned the wood floor I used the rubber caps that came with my speakers (KEF at the time) that fitted over the spikes; now that I rent I spike my stands right into the floor. Nobody but you and maybe the scullery maid is ever going to notice. Seriously, the concept of spikes is to present as small a surface area as possible to the resonating floor while the joint is jumping. Defeat that and you wind up with a compromise no matter what kinda composites you lay down beneath your nifty spikes. Life is short...go for the gusto!
I used some of the dedicated floor protectors for my spiked speakers stands on wood floors--I needed the extra heigth in addition to keeping the landlord happy. I left the plastic on the undersides so I could slide the speaker stands aroud for positioning (three-point). Coins worked well in the past too. No sonic differences I could tell though.
Those little saucers that come along with audio points are claimed by the manufacturer (via instrument measurements) to actually improve coupling, so are not supposed to degrade the effect. If you don't want to use those (agree that sometimes it is inconvenient) what I've done is to save those data CD's that come with AOL junk-mailings, & place them under the spikes so I can slide things around a bit until best placement is determined. After that I remove them from under the spikes leaving nothing underneath, or sometimes then installing the protective coupling saucers. Those junk CD's can also be sawed into smaller size pieces if necessary.
Linn makes floor protectors called "skeets", they are heavy metal discs with holes in the middle for spikes. They slide easily when you need them to, without scratching.
Instead of Stone, I would encourage you to use either MDF, HDF, or Corrian. These materials are more dense in an irregular manner. Stone, Grannite esp. is an amalgum of different metamorphic rocks with very regular crystaline structure, Marble is pretty soft and purous. If you still want to use Stone, use Granite, but do NOT polish it, allow the rough irregular surface to be present so as to remove the pollished mirror effect.
Happy listening
I have audio points under my speakers and have used their discs for my last place's hardwood floor. My speaker are about seventy pounds and three feet high so, I needed another person to help me put the spiked speakers on to the discs. I forgot how exactly how we did that, but it was not easy. I did not, however, have a problem with sliding the speakers around as long as I held the speakers by the bottom edges on both sides. The spikes never came out of the discs as long as I did not lift up on the bottom of the speaker much. The discs work very well by the way. But for anyone interested in getting the audiopoints spikes, you might want to look in to the larger diameters. My smaller diameter spikes have left nasty rings on the bottom of my speakers.
Best use of those AOL CDs I've heard yet. Bravo. I've been using pennies and, believe it or not, one the spikes went straight through one after about a year. Think it would be cost-effective to upgrade to nickles?
Mez thanks for the laugh... Sounds like a cost-effective upgrade although we're talking 3cents to 15cents: a 500% cost increase. Interesting that the spike would drill right through a penny. Aren't all coins a copper sandwich now? The weight alone may not be the only factor, but adding long-term vibration must be enough to do the job. It would only take somewhat longer to drill through a nickel if that's the mechanism.
I use cone coasters by sound anchor (the people who make speaker stands). These disks have a "dimple" in the middle for the point of the spike to set in, and a kevlar/polyester "sandwich" on the bottom, which is easy to slide around. Look them up in Stereophile's recommended components. I have no problem repositioning my 4-spike Alon V's, which weigh upwards of 100 lbs each, by sliding them on the cone coasters. Otherwise, for the best sounding alternative, you can always bolt them to the floor.
Forget the spikes and buy some vibrapods; buy 4 for each speaker not 3 at the proper weight. I used to spike my speakers through carpet to a hardwood floor, but after some experimentation, settled on vibrapods on laminated glass on top of a low pile carpet that I have. If you're a real detail freak, this may not appeal to you, but if you're more into musicality, I'd definitely give the vibrapods a try.
Thanks to all who posted - you've given me a lot to think about. I suppose I can simply spike into my (rented) hardwood floors, then invest in some wood putty to cover the holes when I move...certainly a lot cheaper than *buying* a place in SF ;-)

One thing to note: the "Audio Selection" support cones and disks that AA sells are very nice, but the disks have adhesive tape on the bottom, to hold them in place, for example, on a shelf. I didn't remove the plastic film covering the adhesive, but after sliding the disks around over a few months, the film peeled off...sticking the support disks to my floors. Next time I'll try disks w/o any tape.
I use the new gold/silver dollar. Take four of them, drill a small hole in the center, small enough for the spike not to penitrate to the floor. Run to Home Depot and buy light brown 1" felt stick on discs. They have ones that fit perfect. $5 total and a good conversation piece.
I use granite slabs (1/2" or 5/8" I believe) cut so there is a 1 1/2" border around the speaker bottom or footprint.
Self adhesive felt sheets were applied to the granite bottoms to protect the floors and enable the speakers to slide easily across my hardwood floors without damage. My granite is black and comes polished on the top but once cut the edges are dull. Simple treatment is to apply clear gloss lacquer or varathane to the cut edges and voila, they have a polished "look".

I've found that the granite also helps de-couple the speakers from the floor but still more decoupling was needed. So once I found the ideal speaker location via many placement tests, I then put 2" x 2" pieces of very high density foam under each corner of the granite. Wow!! The high density foam I found effective was one of those long, narrow pieces used in front of computer keyboards to rest the hands on.

Good Luck
Doug Olsen
Doug, I like the hi-density foam trick! Thanks, I'll try that out.