The floor in my listening room is ceramic tile on a a 6” concrete base. It’s basically bomb proof. I placed the Townsends under my Avantgarde UNO’s and was rewarded with a huge improvement in sound. Having had the experience I have, I would say that the type of floor has nothing to do with the sound improvement from the Townsends. BTW I was so impressed with the performance of the Townsends under my speakers, I went out and bought for my amps and equipment rack. Some improvement but nowhere near what I heard by putting them under the speakers.
Townshend Springs under Speakers
I was very interested, especially with all the talk. I brought the subject up on the Vandersteen forum site, and Richard Vandersteen himself weighed in. As with everything, nothing is perfect in all circumstances. If the floor is wobbly, springs can work, if the speaker is on solid ground, 3 spikes is preferred.