On Feb 5, 11:23*pm, "Karl Uppiano" wrote:
Fortunately, long wavelengths and large excursions are
mostly in the low frequencies,

Uh, I would hope long wavelengths are mostly at low
frequencies. :-)

which tend to have minimal out of phase characteristics
(which is why subwoofers are practical).

I assume you mean "single" or "mono" subwoofers here.

I have seen grooves intersect on records that I own,
but the stylus rides a long ways below the surface,
so it is really only a problem if the *bottoms*
of the grooves overlap. Then the stylus would have
a "choice" wouldn't it?
That would be bad...

I have such a record in my collection. It's an old RCA
release of (I believe) Toscanini conducting Dukas'
Sorcerer's Apprentice. At the final orchestral crash
before the concluding section, on playing you hear
the final bars before that note leading up to it and
then, ... nothing but reverb tail. By adjusting the
anti-skating a little on the high side, it would play
just fine. I looked at it with a microscope once and,
indeed, there was a lot of confused grooves for about
2 revolutions.