[78-L] 78 grove spacing

[Rodger J Holtin]

Years ago in some jazz book there was a picture of a Victor master card for
some monumental jazz record - Jelly Roll Morton's Black Bottom Stomp,
methinks - and clearly on the card it enumerated the groove pitch setting.
I'm pretty sure that it was labelled as "pitch."  I had a Victor Revelers
record of Dinah (I think) that had exceptionally wide pitch, short record
but took up all the available space.

The school library here used to have a set of some piece of classical music
on a 12" blue wax Columbia of European origin (six discs as I recall) that
had spacing so narrow that some of the sides played for nearly six minutes.
And some of us have the 10" red label Columbia of Whiteman's Sweet Sue that
was dubbed from the 12" and plays in its entirety on the 10."  Some of the
early copies of the 10" lop off the first flowery intro to squeeze it onto
the 10".

I used to have an RCA promotional LP from the 1960s that had an inner sleeve
that told how they had an additional set of heads on the tape playback unit
that monitored music/sound volume and it controlled the groove pitch
accordingly before that passage reached the actual playback heads that fed
the cutter.

Rodger Holtin
78-L Member Since MCMXCVIII

For Best Results Use Victor Needles

-----Original Message-----
From: 78-l-bounces at klickitat.78online.com
[mailto:78-l-bounces at klickitat.78online.com] On Behalf Of
ron at fial.com.invalid
Sent: Wednesday, August 14, 2019 6:59 PM
To: 78-L at 78online.com
Subject: [78-L] 78 grove spacing


I saw no activity, so I was just testing that everything was OK on the 78-L
server.

Here is a question.   I know that grove excursion must be limited to keep
loud low-frequency  
passages from breaking to an adjacent grove when cutting a record.  This can
be done with level limiter, volume compression and (egads) clipping and low
frequency limiting.

I recall that in the vinyl era there were automatic means to create greater
grove spacing for loud passages.  I could be mistaken.

What methods were used for 78-RPM records.  Was someone riding the volume
control and watching the VU meter, when that came along.  What technologies
if any were used and when did they come along.  There may have been
allowance for the grove getting wider with many playings, right?  I suppose
a microscope used on acoustic and early electricals would 
reveal much.    Any one here already know?

Ron Fial

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