I've got a pair of Klipsch Synergy B20 bookshelf speakers that, for the last year, have been sitting on the floor for lack of a better option. I finally got to build them some speaker stands using the design on this site: http://www.tnt-audio.com/clinica/stubby_e.html. The increase in my enjoyment has been huge. Now I'm wondering about the little rubber feet that came in the box with the speakers--I never put them on, since the speakers were only sitting on carpet. Now that they're on these stands, will sticking those rubber feet on give me better sound, worse sound, or no difference?
Difficult to comment on the rubber feet since I have not seen the ones in question. I might use them if they are thin and pretty solid.
Many people, including me, use small (pea size) blobs of Blu Tack pressure sensitive removable adhesive at the corners for the same purpose. They provide coupling/damping with no chance of real movement.