I first auditioned these in a Denver high-end audio store and was very impressed with what they did for the sound when placed under both the equipment and the speakers (speakers didn't have spikes at the time). So, I bought a few sets.

Since then I've tried them in every imaginable way with both a Linn system and my current system (see below), and frankly I can't tell they make a bit of difference at all. I can't deny what I heard in the store, but I also can't deny that they don't do jack for me now. Well, they do make really good equipment spacers.

For the record, I've also tried sorbothane, vibrapods, AQ Big Feet, and a lot of home-brew things. No effect whatsoever.

Four stars because I know they work.
Four stars for value -- they aren't cheap but they aren't that expensive...

Associated equipment:

Sony DVP-S7000 (CD transport)
Illuminations D-60 digital wire (Great wire)
Lexicon DC-1 DAC/pre
Kimber PBJ interconnects (upgrading soon)
Plinius SA-100 amp (awesome amp)
CAT 5 DIY cables (really nice for the money)
Joseph Audio RM22si loudspeakers

Shawn Harvey

Similar Products Used:

All manner of things...

I put these (MK4) under my HK FL8350 Multi disk CD player and they did help out quite a bit. The sound warmed up somewhat and the bass really tightened up. I didnt get an improvement in soundstage but the system sounds a little more balanced now. With a better system at the stereo store, I heard a much bigger change. I was hoping for a similar large change but at least they do help.