Dear @ferrari275: """
a pure Copper platter mat's tonal characteristics are superior in.........................................................................................
aluminum alloy..........I recall it was thin anemic sounding, not at all musical ...."""
Tonal/anemic characteristics?, I can't understand why we are looking for a kind of sound in the TT mat when what we have to look is for an " inert /non resonant " mat that can damped and don't interfere coloring the cartridge signal.. Metal is resonant no matters its weigth and unfortunatelly resonances/vibrations colors the audio signal and steel is no different. In the aluminum AT the LP is " running " on vacuum and the SOTA is non-metal ones. Normally metal is a bad material in TT/tonearms/cartridges and the like. As less metal in a home audio system as better its quality performance levels. No, we can't disappears metal material from audio items and in some specific items is need it.
R.