Hello all and if you don't mind I'll add a thought or two. As I developed and co-hold the patent on the Auralex Isolation Platform devices, I do have a bit of experience on this topic. Jim, glad you like the device...always great to hear.
The isolation platform is dealing with structure-bourne elements but not the air-bourne. The air-bourne is how the sub couples to room modes, etc...The structure-bourne is in fact very important because sound travels ~ 3x faster (at least) through materials like wood than the speed of sound in air. Secondly, all materials that vibrate in connection with the sub's output are filters (even the isolation platform). The goal is to have the combination of sub to surface be a positive one (as close to linear as possible).
Some of the variables at play are the subs composition and build, the isolation platform's composition (resonant freq, deflection) and the floor's composition.
Not all subs would benefit from such a device, not all floors would benefit either.
The R&D process of the device was anchored around my pro bass playing career and the frustration of my rig's tone changing from stage to stage. It didn't take long to find other applications for the Auralex GRAMMA (which is the core product...renamed SubDude for this market).
