Extensive discussion on this topic here. I've since moved to Magico M3s with MPods which perform the same isolation role. I'd certainly never go back to a spike based solution
https://forum.audiogon.com/discussions/speaker-isolation-experience-with-townshend-seismic-isolation...
https://forum.audiogon.com/discussions/speaker-isolation-experience-with-townshend-seismic-isolation...