I agree with Hdm about mass loading but disagree about the mass. A couple of Emag audio reviewers live here in town and they mass load their transports/players with Lead Shot. Go to gun shop or some hardware stores and get Lead Shot in canvas bags and put those bags in thick plastic bags (like Zip Lock or black (more cosmetically pleasing) which has a Much higher specific gravity and less ringing than baked clay (bricks). The lead can flow in bags to fit the contours of player and will not run risk of scuffing surface if you double or triple bag. Another, less desirable but still better than bricks, is iron weight lifting plates placed on a thick foam mouse pad or better yet go to Menards and get some of the recycled automobile tire pads and place them on your player to distribute the load (this applies to lead shot as well). Of course, having a wobbly base and stand underneath the player can help remove any benefit top loading can do. Good luck!
