All the CD player trays I have seen are already black. They sound GREAT. I don't need to make the tray blacker! My favorite new crazy thing to do is place a refrigerator white board. the sort with a flexible magnetic backing UNDER the CD player. So the magnetic mat is about a half inch below the player. The mat on the shelf under the player's feet. Works. blacker background. better detail. (not stuck on top, not good)
Cost is $10 to $20 off Amazon. And guess what? it it does not work for YOU.. Stick in on your fridge.! Draw smiley faces..
Maybe I need to start my own company. Sell the $10 to $20 device for $599. Claim it has been treated with quantum whatever. "Electratomically-molifigrated" with an ultraviolet ray. derived from mini artificial atoms being made into black holes. I bet ten times more folks would try it than saying it is a fridge magnet costing $10 to $20. and from Amazon. LOL