I was going to say Townshend Platform until "don’t want to spend money" at which point we are SOL. Even a sand box costs money! Your answer is springs. The other stuff you are doing, no amount of cork or sorbothane ever gonna fix this. Nobsound springs are dirt cheap- $30 per set of four. Then when you realize springs are the answer hopefully the next step is to realize really well engineered springs will be even better, at which point you get the Platform and are amazed, and move the Nobsound to some other components. Because for sure they are better than whatever is under them now.
You can also talk to John Hannant at Townshend about getting some springs for the rack. This is not "off the shelf" but they have done stuff like this for others, are helping someone I know right now in fact. You can also do both. The Platform is probably the easier thing to try first.
You can also talk to John Hannant at Townshend about getting some springs for the rack. This is not "off the shelf" but they have done stuff like this for others, are helping someone I know right now in fact. You can also do both. The Platform is probably the easier thing to try first.