Good question, Ralph. I suspect that my spectrum analyzer is too slow - but I’m sure that it’s too heavy! That will have to wait until I have help to move it.
However, since the AP LP was an order of magnitude quieter than the other LP at all frequencies, and only somewhat more audible at 400Hz than at other frequencies, does this not suggest that the coupling is pretty good? Agreed that 400Hz seems less good... The graphite platter has a natural resonance of 2KHz, the cast iron subplatter of 500Hz.
Settled on this configuration after other platter pads sounded muddy by comparison.
However, since the AP LP was an order of magnitude quieter than the other LP at all frequencies, and only somewhat more audible at 400Hz than at other frequencies, does this not suggest that the coupling is pretty good? Agreed that 400Hz seems less good... The graphite platter has a natural resonance of 2KHz, the cast iron subplatter of 500Hz.
Settled on this configuration after other platter pads sounded muddy by comparison.