I have not tried this, but I thought that maybe a piece of acrylic(or something similar) under the spikes would do the trick. A piece maybe the same size as the speakers or a little bigger. Sometimes you need to sacrifice a little sound quality and protect your property.
New Soliloquys with spikes and hardwood floors
I'm a newbie so don't laugh. I just bought a pair of 5.3's and at 80lbs apiece, how do I keep them from burrowing into my livingroom floor?! On hardwood floors, should I use the spikes or something else to isolate them? Any help would be appreciated! Thanks, Mike.