Do speakers sound better on wood floor or concrete

Was having a discussion, my friend says wood floors, I'm not sure it matters

Interesting question, but....nobody wins the bet, too many variables. Wood may resonate more than concrete, but at what frequency? Most concrete floors are covered in carpet which dampens the first order reflection from the floor. Bass travels through and resonates most solid surfaces, regardless of the material. In my view, the best surface is a hand-laid hardwood floor on a solid subfloor using the came wood as the floorstanding speaker cabinet, with an authentic hand-made Persian rug to soften the first reflections!
The floor should not be part of the sound at all - at least not directly from the speakers' bodies! That's why you use spikes, antispikes and the like!
The great concert halls have wood floors, so I'm guessing that's the absolute best you can do, if everything is just right, wood wins. That of course is just for arguments sake, as a real world practical issue it depends on many construction variables.
A lot of it has to do with the structre of the floor. Is is a wobbly suspended wooden floor with a basement like I have? I had to cut away the carpeting, screw down 3/4" plywood and then install floorjacks right under the speakers from the basement. It worked wonders! Also kept floor vibrations away from the rest of my system especially my turntable. In fact in did the same thing to my TT. My basement doesn't look real nice, but no buddy goes down there anyway. And good spikes are a must.
Good Luck!
My KEF Reference Twos are on a tile ledge about 8" high that is part of a built in wall unit. The ledge is the bottom of the wall unit and extends out about 17" in front of the shelves. It is hollow underneath the tile but fairly solid. I'm currently just using the round feet (no spikes) that came with the KEFs. Should I mass load the plinths, add some rubber or sorbothane under the feet or put on the spikes? Anything else I can do to tweak? My components are on the same ledge in between the KEFs but they have 4 Vibrapod Cones under each piece. Should I put Vibrapod Isolators under the round KEF feet?

Thanks for any advice,

I Like the wood I have one system in my basement on concreat and one upstairs on wood. The wood room just has a softer sound but still has a snap to the music the concreat really dampens the bass and the carpet softens the highs. The key here is to speakers that can be dialed into any room.

I aggree with the firs comment to many variables. size and speaker position are much more important.
Concrete, unlike wood, does not audibly resonate. Concrete, with or without rugs, does nothing to bass - rugs will not absorb bass frequencies. It might sound damped compared to wood because the wood augments the bass via resonance/vibration (even with spikes). There's a "whole world" dedicated to "room tuning" and it based on the fact that wood resonates and by doing things to the wood will control the resonance that modifies the sound. This is also somewhat separate from acoustically treating the room to (hopefully) get rid of "hot and cold" spots in the room and the reflections that cloud the intended sound when using your speakers/gear. Given the choice between concrete and a "regular" wood floor, I'd take concrete - you can always add something later modify the sound if you think it's needed.