If you only desire to protect the flooring, I would recommend Audio Points Coupling Discs – made of solid brass with a smooth floor service. Stone even polished versions in contact with wood can scratch (more like scuff) finished flooring as well.
If you are searching to increase the sound quality from your loudspeaker, possibly double your enjoyment of listening and really hear your speaker investment for the first time, I would recommend Audio Points replacing the spikes.
As quoted by Ernie Fisher – Editor The Inner Ear Report – Volume 13 #2, 2001 –
“Folks with spiked floorstanding loudspeakers, regardless of make, should replace the spikes with Audio Points, for the audible benefits here are considerable and quite appreciable”.
The Audio Point is unlike any other cone or spike type product in the Industry. Have a look see at www.audiopoints.com.
To further your understanding of dynamics associated with coupling, de-coupling, absorption, isolation and The Science of Resonance Energy Transfer (a new way of dealing with detrimental resonance) telephone them.
Good luck with your floor and as always - Good Listening.
Robert