"Arny Krueger" wrote in message
...
"David Nebenzahl" wrote in message
s.com

I've heard it a number of times over the years on first
play of a vinyl record, on both 33 and 45 rpm discs, and
the pre-echo has always been *exactly* one revolution
ahead of the peak, both on the lead-in and between
tracks or in quiet passages. I'd put it down as an
artifact of either the material of the master deforming
slightly while being cut, or distortion of the plastic
while the hot record was cooling after coming out of the
mould.

The former being the most likely. Remember that when hot plastic is being
deformed to create grooves, it is being supported by the die. When the
lacquer is being cut, the previous groove is not being supported by
anything but air.

Exactly. And in addition the lacquer surface is softened
to some extent by the physical heating of the cutter stylus
for a quieter cut.

Iain