The socks were just plain socks. They were, however, clean.
The towers didn't get spikes because I'd read that coupling speakers to a wood floor wasn't good. It's a tough room for audio because of the wood floor ... there's a crawl space on one side that has to be completely avoided. Putting the towers in their current spot, sans crawl space, was a major improvement. So the floor is definitely part of getting the sound right.
Coupled or not, spikes on the towers would also make them insanely difficult to move compared to socks or some sort of slider.
In a few weeks when the air conditioners go off it'll be time to play around some more. Maybe the socks really do work better and I'm just reacting to the change in tonality. That happens all the time: make a change, proclaim it better. Wait a month, change it back and proclaim it better.