You can try these
Pads can are good up to 60 lbs per square inch. thats 960 lbs per individual pad.
4 PACK ANTI VIBRATION PADS ISOLATION DAMPENER SUPER HEAVY DUTY BLUE 4x4x7/8 | eBay I have used these under speakers and to also isolate my TT
free shipping also 2 packs should be enough for both speakers at a cost of $26.00
free shipping also 2 packs should be enough for both speakers at a cost of $26.00