Stringreen, I respect your musical knowledge and experience, but I believe you are wrong about "acoustic feedback". My simple understanding is that it is the airborne (i.e. acoustic) waves from output back to input. The most common example most of us have heard is an improperly set up microphone in a auditorium which howls from the sonic loop from PA speaker back to the mic.
Similarly, a turntable/arm/cartridge system is subject to the sonic energy, particularly low frequency tones, from the speakers. Wall mounting will only be effective if it moves the tt system away from a bass node loading area. It is not related to a springy floor. In extreme cases I've seen the tt system placed in a separate room from the speakers to minimize acoustic feedback. Fortunately most of us don't need to go that far.
This is why I suggested consideration of all three conditions for unwanted energy in my post above.
Similarly, a turntable/arm/cartridge system is subject to the sonic energy, particularly low frequency tones, from the speakers. Wall mounting will only be effective if it moves the tt system away from a bass node loading area. It is not related to a springy floor. In extreme cases I've seen the tt system placed in a separate room from the speakers to minimize acoustic feedback. Fortunately most of us don't need to go that far.
This is why I suggested consideration of all three conditions for unwanted energy in my post above.