A couple of years ago I allocated a solid week to coupling/decoupling devices for disk players and turntables, comparing about 20 different methods. For optical disc, magnetic levitation emerged as the sonic game-changer. The improvement was transformational, even on a (at the time) middling original Oppo bdp-83 doing Redbook and SACD duty. If your optical player is light enough, the Yeil Spike Sound Will levitation feet are affordable and effective. There are other more exotic ways to get mag-lev.
The 2nd most effective improvement for optical disc came from Aurios Classic Media Bearings, which are also relatively inexpensive in this realm. My listening tests were done on glass, MDF and 3-1/2" thick solid maple surfaces. The mag-lev solution was equally effective on all surfaces, nearly eliminating the sonic differences between them. Glass sounded as good as solid maple, with mag-lev. For Aurios, glass was not their friend, but differences between maple and MDF were sharply diminished.
For turntables, I found Aurios to be most effective, with mag-lev behind it, and much less practical given the mass of the turntable I used. Since I've done this comparo, the main significant new entry has been Black Ravioli, which I haven't tried yet.
With mag-lev, you have to match the support capacity of the devices to the weight of your player, and then work to arrange them equally around the center of gravity. Placement of maglev under the three or four factory feet is not always correct. With no other change, the right support yields punchier dynamics, smoother top end, less strain and grain in the midrange, higher-definition bass, improved soundstaging/dimensioning and a general reduction of digital hash. A portion of digititis normally blamed on jitter can be mitigated through maglev or bearings.
Phil
