I've long resisted trying isolation devices under my speakers because the logic seemed so...well... counterintuitive. Recently, I decided I didn't like the Stillpoints Ultra Aluminum isolation devices directly under ("coupled") to a couple of my components. Hearing changes in the tonal balance every time I moved the devices a fraction of an inch here or a fraction of an inch there conviced me that when directly coupled to the chassis, the isolation devices were adding their own signature or, to put it less kindly, coloration. So I chose to place the components on their own feet on the Stillpoints ESS AV rack.
Suddenly I had 8 expensive Stillpoints Ultras lying around so I thought "what the heck" and replaced the speaker spikes on my Aerial Acoustics 7T with the Stillpoints. Big improvement. No sonic trade off. I don't understand it!