I think Mrtennis has it correct or at least has had similiar experiences to mine. I've had many CD players, transports and DAC's and found a wide variance in what coupling and isolation devices can do, that includes mats and shelve's made of many different natural and exotic material's, cones, balls, spring's, spikes, ect, ect. I have not tried active isolation. My current setup is a great example, my Ayre CD5MP prefers a solid carbon fiber base while my Audio Research DAC8 insists on being directly coupled to the two inch thick wood shelf thats part of my stand, put anything under the DAC8 and it protests with audible anomalies.