Hi George,
This issue of speed at 60 Hz vs 50 Hz has long been source of confusion because, on the face of it, the duration of 1 minute is the same everywhere, and a given number of revolutions during that time period should be the same regardless of the line frequency. Here's a hypothetical question: Let's say we have a Technics
SP-15 turntable, which is digitally-controlled and has regulated, switching-mode power supplies. As such, line frequency and voltage are irrelevant to its operation. If this turntable is operated in a country where the mains frequency is 50 Hz, are you suggesting that achieving 78.26-rpm requires setting this turntable's digital readout to -0.4 % to achieve 77.92?
I pose this question because I know a lot of people were confused, decades ago, by the two strobes that Aida included with her Caruso book. Many still are.
Best,
Gary
____________________________
Gary Galo
Audio Engineer Emeritus
The Crane School of Music
SUNY at Potsdam, NY 13676
"Great art presupposes the alert mind of the educated listener."
Arnold Schoenberg
"A true artist doesn't want to be admired, he wants to be believed."
Igor Markevitch
-----Original Message-----
From: Association for Recorded Sound Discussion List [mailto:[log in to unmask]] On Behalf Of George Brock-Nannestad
Sent: Monday, April 24, 2017 6:43 PM
To: [log in to unmask]
Subject: Re: [ARSCLIST] How many half-tones from 78 rpm to 80 rpm
From: Patent Tactics, George Brock-Nannestad
Hello,
all very US-centered, isn't it? The 78.26 comes from a certain number of poles in a synchronous motor combined with simple ratios in the gearbox that changes the rpm from the motor to the target rpm for the turntable. But it is only this figure at 60 Hz mains frequency. If you had a slow-speed synchronous motor run off 60 Hz the closest to 78.00 is 78.26 rpm. If you use a stroboscope for 60 Hz under a 120 Hz light (goes for fluorescent or low-power incandescent lamps off the mains), you can only get a stationary ring at 78.26.
In the not insignificant parts of the world where they use 50 Hz as the mains frequency, the corresponding figure would be 77.92 rpm. You need a different stroboscope for this and also the slow-speed synchronous motor would have a different number of poles. Aida Favia-Artsay knew, and her Caruso stroboscopes came in both varieties.
The Victor Talking Machine Company is on record in the acoustic period as specifying 76 rpm for recording and 78 rpm for reproduction of the recording obtained. Some of their customers obviously did not have absolute pitch. In the acoustic period of the Gramophone Company, the speed was checked every morning by means of a piece of cigarette paper under the wax while cutting and counting the revolutions for a minute. They preferred 78 rpm!
In the United Kingdom, the Old Philharmonic Pitch (which corresponded to an a4 of 452 Hz (give or take a few) survived in the military bands until ca. 1926, when they also changed to the New Philharmonic Pitch at 439 Hz. If you hear Nellie Melba sing accompanied by the Band of the Coldstream Guards in 1905 with the key indicated, you can pitch it absolutely correctly when you play it: they used the Old Philharmonic Pitch. Columbia recorded a lot of military bands, and they abandoned the 80 rpm speed for 78 rpm at around the same time the bands changed tuning. The interesting thing is that the fraction 78/80 is very nearly the same as the fraction 439/452, in other words if you played a Columbia band record in 1932 you would not know whether it was an early recording slowed down to 78 or whether it was actually a new recording with the new pitch and the new speed. This is what I habitually in my workshops call "the dialectic triangle:
speed, key, and standard pitch".
I rarely comment these days, but this issue is very important.
Best wishes,
George
---------------------------------------------
> 78.26 did not become a standard speed until electric motors were used
> in cutter and playback turntables. In the acoustic era, 78 usually meant 78.00.
> But, if you´re using a modern turntable like, say, a Technics SP-15,
> 78 actually is 78.26, and the percentage of change must be calculated
> from that.
>
> Gary
>
> ____________________________
>
> Gary Galo
> Audio Engineer Emeritus
> The Crane School of Music
> SUNY at Potsdam, NY 13676
>
> "Great art presupposes the alert mind of the educated listener."
> Arnold Schoenberg
>
> "A true artist doesn't want to be admired, he wants to be believed."
> Igor Markevitch
>
> From: DAVID BURNHAM [mailto:[log in to unmask]]
> Sent: Monday, April 24, 2017 6:05 PM
> To: Gary A. Galo
> Subject: Re: [ARSCLIST] How many half-tones from 78 rpm to 80 rpm
>
> That's fine, but the standard speed for 78s IS 78.26; I don't know if
> 80RPM records included a fraction. LPs, of course are always based on
> 33 1/3 RPM, so there would be no reason to relate anything to 33.00
> RPM. I'm sure the original question was searching for a corrective
> adjustment to adapt from standard 78 to Columbia's 80 RPM, but that's only a guess.
>
> db
>
>
>
> On Monday, April 24, 2017 5:56 PM, Gary A. Galo
> <[log in to unmask]<mailto:[log in to unmask]>> wrote:
>
> I specifically said 78.00 in my reply. I assumed that if you meant
> 78.26, you would have said so.
>
> Gary
>
>
> -----Original Message-----
> From: Association for Recorded Sound Discussion List
> [mailto:[log in to unmask]<mailto:[log in to unmask]>]
> On Behalf Of DAVID BURNHAM
> Sent: Monday, April 24, 2017 4:44 PM
> To: [log in to unmask]<mailto:[log in to unmask]>
> Subject: Re: [ARSCLIST] How many half-tones from 78 rpm to 80 rpm
>
> Are you basing that on 78.00 RPM or 78.26 RPM?
> Not challenging you just a question.
> db
>
> On Monday, April 24, 2017 4:18 PM, Gary A. Galo
> <[log in to unmask]<mailto:[log in to unmask]>> wrote:
>
>
> A quarter tone is 3%, a half tone is 6%, and a whole tone is 12%. So,
> the difference between 78.00 and 80 is just a hair under a quarter
> tone. A quarter tone would be 80.34; a half tone is 82.68..
>
> Gary
>
> ____________________________
>
> Gary Galo
> Audio Engineer Emeritus
> The Crane School of Music
> SUNY at Potsdam, NY 13676
>
> "Great art presupposes the alert mind of the educated listener."
> Arnold Schoenberg
>
> "A true artist doesn't want to be admired, he wants to be believed."
> Igor Markevitch
>
> -----Original Message-----
> From: Association for Recorded Sound Discussion List
> [mailto:[log in to unmask]<mailto:[log in to unmask]>]
> On Behalf Of James Roth
> Sent: Monday, April 24, 2017 3:31 PM
> To: [log in to unmask]<mailto:[log in to unmask]>
> Subject: [ARSCLIST] How many half-tones from 78 rpm to 80 rpm
>
> Hello everybody,
>
> Can anyone tell me how many half-tones up from 78 rpm to 80 rpm?
>
> Thanks.
> Ben Roth
>
>
>
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