SVS Subwoofer Isolation feet. Will I lose bass?

I must wait to sell my house but I cannot wait to experiment with my speakers and add to my sandwich of 5 different materials under them 4 springs and directly under the speakers a bed of quartz sand/ small peebles. The sandwich between them....

I trust the springs to isolate from external vibrations, and for the quartz bed to manage gently internal resonance with the sandwiche… :)


 

Looks like I dropped a grenade. :)

Let me clarify what I was thinking about driver/cabinet motion.

The combination of small footprint, light weight, and distance from the floor are what make this issue most prominent. If you have smallish stand-mounted monitors I encourage you to try some weight on top and listen. 

Would it happen with a big heavy woofer, inches from the floor? Probably not nearly as much, but I certainly don't want it spring loaded to the floor any more than necessary.

 

My speakers actually were loaded with 70 pounds on each, and this was good... I will try someday juste the springs compared to the speakers loaded with weigh on my sandwiches....The weigh gives some damping, and the different densities materials I use give some coupling-decoupling but also some tuning.... I will compare someday with the springs with a bed of quartz....

So....i have an SVS SB16 and have it on a carpeted floor. Tried it without feet and the bass was bloated. The SVS feet helped tighten things up with not a significant loss. I then went to isoacoustic Gaia II with carpet spikes and everything is significantly tighter/cleaner than the SVS but you lose some of the chest rattle. 

My vote would be: If your looking for musicality the isoacoustic is the way to go. Dual purpose for music and theater the SVS feet are fine and enough of an improvement to atleast compensate for moderate cost. 

Good illustration of how carpets act as springs. Two spring systems one on top of the other is bad news. It’s like driving down the road in a car with two springs one on top of the other for each wheel.. It will be a very b-b-bumpy ride.