Isolation Sand Boxes

Is it because you put the sand in one of the boxes while the CD player was in the box?

On a more serious note, and assuming you have placed the CD player on the sand (be careful with that) or a non-resonant platform on the sand, my observation is that Glen does win. You are doing a superior job of isolating the CDP from its environment and in damping the vibrations eminating from the CDP itself. When I placed my SACD player on an Isobase (an isolation platform manufactured by one of our NJ Audio Society members which uses a small, silicone and air filled innertube in a base with a lead and sand mixture) I would swear to you that the player's volume level increased 2 db. Lowered noise floor, who knows? But very effective.

I tried quicksand, and it was great for the 45 seconds that the CD player stayed in sight.....

Buckingham, BIG mistake with the Florida sand, far too coarse for your purposes. If you can make it to the Sahara, now there's the ultimate...