I used to put lead weights, both discs and blocks, on top of all my studio electronics and stereo equipment to kill enclosure vibrations. Using ’em with CD players, amplifiers, etc., gave music more punch. But my initial satisfaction was blown to bits when I tried brass. Brass weights carry even more punch than lead—and there’s more sparkle in the details with much better dynamics. I tried the other common materials too (sand, stone, iron, VPI bricks, Shaktis). They’re better than nothing, but don’t compare with brass.