I'm going out on a limb here. REAL wood floors, (vs laminate) like solid wood strip flooring or wood parquae tiles reflect, yes, but they also absorb. It is this absorption that gives it a sonic quality that is hard to pinpoint, but it definitely exists. Concrete on the otherhand, does not absorb, at least not the way a layer of wood does. Also, different species, such as Maple and Oak have different absorption coefficients. It used to be, studio designers would take this coefficient into consideration when calculating the total absorption in the room, as EVERYTHING absorbs to some extent, even human beings in the room.