[78-L] David Hall the prophet

[Michael Biel]

From: DAVID BURNHAM <burnhamd at rogers.com>

> He dances around, but doesn't mention the very single development which
> allowed Columbia's Lp to succeed, (and by its absence, RCA's transcriptions
> to fail).  That is the microgroove technology.  As we all know, all other
> things being equal, a 78 should sound better than an Lp because of its
> faster recording speed.  However, the two specs which determine the high
> frequency capability of a disc recording is playing speed, (by which I
> mean the speed at which the surface travels under the stylus, not r.p.m.),
> and stylus diameter, so while a 78 rotates slightly more than twice as
> fast as an Lp, its stylus is 3 times bigger, therefore higher frequencies
> can be recorded on an Lp than on a 78.  A 3 mil groove would have to be
> recorded at 100 r.p.m. to sound as good as an Lp.  db

The other variable is the diameter, since the surface speed is much
higher at the outer edge with constant rotational speed.  Some of the
earliest LPs had large lead-out areas to keep to as far out as they
could -- until customers complained about all the wasted space which
could be used for more recording time.  

This is where the 7-inch 45 was originally superior to the LP.  There is
too much difference in surface speed from the outer area to the inner
area of a 10 and 12 but very little difference on a 7-incher, especially
before the EP.  So there was a greater consistency from the end of one
side to the beginning of the next in the 45, and with the super-fast
changer that was originally marketed, there was less difference in sound
quality in continuous works.  There would be longer pauses between LP
sides, and unless a work was able to fit on one LP side, there would be
an interruption to turn the record over or change to the next side on an
automatic if it was a set.  And contrary to popular folklore which had
the 45 hurredly invented to soothe the rivalry between Sarnoff and
Paley, RCA had been working on the 45 longer than Columbia worked on the
LP.

Mike Biel  mbiel at mbiel.com