My speakers weigh about 70 pounds apiece, and are on heavy duty Berber carpet. Since I frequently move them from a whole room, straight out listening position, to a toed in home theater listening position, I put smallish heavy duty carpet sliders on the four corners. This makes for an easy move, and the HT position is marked in tape for easy re-positioning. To my tinnitus addled 62 year old ears, no difference in SQ was detected.
Caster Wheels vs. Spikes
My Tekton Double Impacts came with caster wheels, which made them very easy to move and reposition. They are sitting on probably fake wood floors in my apartment. They sound great now, but I can't help but wonder if I'm leaving SQ on the table by not having them on spikes. Some people say I must use spikes, others (including Erik Alexander) say wheels are just fine. They are super heavy so the wheels are not easy to take off. I want to make sure it's worth doing. What are your experiences and thoughts?