As was posted wood will vibrate and these vibrations are too often not controlled.
Impression of BIG bass,the floor vibrates and creates a tactile transducer effect.No Clark devices used
Boom and unwanted noises caused by the non rigid floor.
Now with concrete you may not get the shaking effect buy you get much cleaner bass and almost eliminate the nasty peaks created by a live floor.
Where I live the floor resides on thick concrete and no squeaking or overblown vibrations take place even above 115dB(listening position)when my subs are blasting.
WIth my PC systems its another story,as the subs rest on an elevated mezzanine.The bass effect is FAT but detail is much lesser.And yes the glorious shaking is all there.
Any accurate system should rest in a room where the floor is very inert and where the room is treated with acoustic panels plus some bass traps. All thisin the name of purity and lack of colorations.
OUPS I have to learn to look better...pressed NEW THREAD DUH