[78-L] (no subject)

[Chris Zwarg]

At 07:20 15.10.2008, you wrote:
>----- Original Message ----- 
>From: "Howard Friedman" <hsf318 at comcast.net>
>> To Malcolm and others,
>> You're quite right, turntable speed is controlled and regulated according 
>> to gearing.  In the US using 60 cycle current, the turntable speed is 60 
>> squared, or 3600, divided by a number usually between 60 and 40, i.e., 
>> between 60 and 90 rpm.  For 78.26 rpm, the gearing is 3600/46.  In Europe 
>> where the current is 50 cycles, the gearing would be between, say, 50 
>> squared or 2500/50 to 2500/25, or from 50 to 100 rpm.  In the old days 
>> when recording machines were operated on batteries, or even electric 
>> motors that were operated on highly variable electricity, 

I repeat: ACOUSTIC RECORDING MACHINES WERE USUALLY NOT DRIVEN BY ELECTRIC MOTORS! Both pictures and surviving parts of equipment show falling-weight "gravity motors" on stationary machines, while smaller, portable disc recording lathes often used spring drives like your ordinary gramophone. In the very early days, Berliner and Gaisberg experimented with battery motors - the resulting records were much more problematic for wow and "varispeeding" than those made in the studio with the falling-weight drive, and the traveling engineer would have to cope with heavy lead accumulators containing unpleasantly large amounts of acid.

The figures like "78.26" you are quoting are the speeds associated with stroboscopic rings lighted by a 60Hz resp. 50Hz A/C-powered bulb. I think it was William Moran who started to quote these numbers as "recommended speeds" in his discography, giving a false impression of accuracy - I defy anybody to determine a recording speed reliably within TWO DECIMALS (circa 0.1 %) by aurally tuning the record and then looking at the stroboscope!! If you see "78.26" in a discography it simply means the stroboscopic ring so labelled fits best. Actual recording speeds DID NOT MOVE IN STEPS, much less were they determined by gearing - recording machines had *continuously adjustable* friction regulators just like any wind-up gramophone (which, as we have seen, all-too-often disadjusted themselves equally continuously during the actual recording, resulting in "varispeeding" records for which, curiously enough, usually a single "average" speed is given in discographies, still with an apparent two-decimals accuracy). 

Chris Zwarg