[John Phillips]

On 2007-06-30, William Sommerwerck wrote:
The BEST turntable you can buy is a Neumann record cutting lathe.
You can get them for a few thousand dollars if they do not come
with the desirable stereo cutting heads and mastering chains.
Anyone who says any audiophile table yet made is any better is
full of **** and knows it. Other pro lathes are okay and less money.

There are good reasons why a high-quality audiophile turntable might very
well be better than a Neumann. To wit, having a plastic platter that makes a
good impedance match with the vinyl of the LP.

OK, so you get substantially all unwanted acoustic energy out of the vinyl
and into the platter by matching the acoustic impedance. But where does
it then go?

Through the bearing? Not much I suspect. There's the plastic/metal
impedance mismatch to start with and then it's only a small area for
transmission.

I suspect the unwanted acoustic energy (assuming a longitudinal wave)
gets mostly reflected back at the platter/air boundary impedance
mismatch underneath the platter and then gets transmitted back to the
vinyl because of the excellent vinyl/platter impedance match.

The only hope is for the platter to be acoustically lossy. Ideal
materials aren't lossy, of course. But I have never looked up the
acoustic loss coefficients of real plastics so I don't know if this is
a reasonable hope.


--
John Phillips