I cannot tell you how frustrating my experiences have been with regards to your question. I have tried both with a multitude of speakers and can honestly say I don't know the answer. Coupling the speaker to the wooden floors just make the floor part of the speakers vibrating them. Isolating the speakers just means they will vibrate longer and accentuate the resonant frequency of the combo of the speakers and the absorbent material.
This is really just another case of vibrations elsewhere in your system such as the turntable or cd player. There I have found the active isolation base made by Halcyonic neither has a resonant frequency nor couples the unit to the stand. Speakers on the Halcyonics might be exceptional, but I will never know as I cannot afford more of the Halcyonics units.
Mass is probably important as it lowers the resonant frequency. You might want to put thick granite on a soft material and put the speakers on top. You will probably have to experiment with what this material should be.
This is really just another case of vibrations elsewhere in your system such as the turntable or cd player. There I have found the active isolation base made by Halcyonic neither has a resonant frequency nor couples the unit to the stand. Speakers on the Halcyonics might be exceptional, but I will never know as I cannot afford more of the Halcyonics units.
Mass is probably important as it lowers the resonant frequency. You might want to put thick granite on a soft material and put the speakers on top. You will probably have to experiment with what this material should be.