Glass is also used for LP platters, where resonance can be a big problem...
It is the implementation that counts.
All my racks (cheap sand filled metal and glass) have glass shelves.
I used sorbothane-like mats (again, cheap.. chemistry 7mm thick experiment placemats same material as bottle stoppers.. I got super cheap at American Science and Surplus..) that I cut into squares. some full size component, some 4" square. some 2" square, and experimented.
Agree that often gless shelves do benefit from a rubber energy absorber between the component and the shelf.
It is the implementation that counts.
All my racks (cheap sand filled metal and glass) have glass shelves.
I used sorbothane-like mats (again, cheap.. chemistry 7mm thick experiment placemats same material as bottle stoppers.. I got super cheap at American Science and Surplus..) that I cut into squares. some full size component, some 4" square. some 2" square, and experimented.
Agree that often gless shelves do benefit from a rubber energy absorber between the component and the shelf.