I have yet to try springs under my speakers, but am intrigued. Our last house had a carpeted concrete slab in the livingroom....coupling 100# speakers by spiking through the carpet to the heavy mass of the slab seemed to work well vs no spikes.
Our current house has a large carpeted suspended frame floor with plywood floor panels....coupling the same speakers to that floor with spikes exaggerated floor resonance. Removing the spikes and letting the carpet and pad decouple the speakers offered better bass in that room. Springs would make sense in this case, but I have had success spiking into concrete slabs, so it may depend on the particular situation.
Our current house has a large carpeted suspended frame floor with plywood floor panels....coupling the same speakers to that floor with spikes exaggerated floor resonance. Removing the spikes and letting the carpet and pad decouple the speakers offered better bass in that room. Springs would make sense in this case, but I have had success spiking into concrete slabs, so it may depend on the particular situation.