Seeking suggestions for a material to place between the bottom of a speaker and the top of a heavy wood cabinet to protect both but, the cabinet in particular from scratches, etc. The situation is for a non-audiophile brother who asked me to help with assembling a decent stereo system. The speakers are Dynaudio Evoke 20 bookshelf style. They weigh about 22 pounds each. My first thought was that black and sort of foamy drawer liner material, which would be quite thin and essentially invisible. This is mostly about function rather than sound enhacement. Ideas?