Blueranger,
Just using springs will be wobbly. If you are targeting 2-3hz resonant on the springs, then most higher frequencies will not be transmitted .. it flops. If you add dampening in parallel with the spring (ie sorbothane), then you can keep a low resonant frequency, but damp oscillation. Some higher frequencies will now pass (still highly attenuated), but the system will not feel nearly as "floppy" as the resonances are damped.
Wrt Clearthink's post on just adding mass, all that does is change the resonant frequency of the speaker/mass and spring (i.e. your floor). The spring constant, i.e. your floor does not change. As I mentioned above, a wider stiff base (ie your granite bases) does change your floor interface which may transfer weight closer to the joists which will change your spring constant (floor).
Where Geoff and I agree is on a spring loaded floor isolation is better. I prefer damped as that damps out cabinet vibration and isolates from the floor.
Just using springs will be wobbly. If you are targeting 2-3hz resonant on the springs, then most higher frequencies will not be transmitted .. it flops. If you add dampening in parallel with the spring (ie sorbothane), then you can keep a low resonant frequency, but damp oscillation. Some higher frequencies will now pass (still highly attenuated), but the system will not feel nearly as "floppy" as the resonances are damped.
Wrt Clearthink's post on just adding mass, all that does is change the resonant frequency of the speaker/mass and spring (i.e. your floor). The spring constant, i.e. your floor does not change. As I mentioned above, a wider stiff base (ie your granite bases) does change your floor interface which may transfer weight closer to the joists which will change your spring constant (floor).
Where Geoff and I agree is on a spring loaded floor isolation is better. I prefer damped as that damps out cabinet vibration and isolates from the floor.