I’m toying with the idea of bringing my old Quads out of storage and the only place I have available would involve hanging them upside down from the joists in my basement. I had seen this done before in a record shop I used to go to so was thinking of doing the same. My thought was eye hooks into the joists, eye hooks with nuts and washers into the Quads and extension springs hooked between the eye hooks to suspend and isolate the speakers from the floor above. My concern was whether the wood frame of the Quad could support being suspended in such a manner and making the correct choice of spring for the application. I imagine I would want the resonance frequency of the spring to be below 10 HZ, lower the better. The speakers weigh 40 lbs so I was thinking one of these two springs might work: 0.812"OD x 0.120"Wire 4"L Loop End #76 Steel Hard Drawn MB Extension Spring | Fastenal 0.531"OD x 0.091"Wire 3-1/2"L Loop End #80 Steel Hard Drawn MB Extension Spring | Fastenal Any ideas?