Standard RPM counts?

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TL7
Posts: 9
Joined: Tue Oct 31, 2017 6:53 pm

Standard RPM counts?

Post: # 48959Unread post TL7
Tue Jan 16, 2018 7:54 pm

I have two questions:

1. Why/How exactly were the RPM counts 33,45,78 standardised?
2. Are there any other lesser known standard RPM counts above/beyond and below 33,45,78?

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Ritter
Posts: 28
Joined: Tue Nov 01, 2016 3:37 am

Re: Standard RPM counts?

Post: # 48961Unread post Ritter
Tue Jan 16, 2018 10:15 pm

1.

78s -

"The literature does not disclose why 78 rpm was chosen for the phonograph industry, apparently this just happened to be the speed created by one of the early machines and, for no other reason continued to be used" from https://en.wikipedia.org/wiki/Phonograph_record#78_rpm_disc_developments

OR

"78 rpm was chosen as the standard because of the introduction of the electrically powered, synchronous turntable motor in 1925, which ran at 3600 rpm with a 46:1 gear ratio, resulting in a rotation speed of 78.26 rpm." https://en.wikipedia.org/wiki/Single_(music)

45s -

"The 7-inch 45 rpm record was released 31 March 1949 by RCA Victor as a smaller, more durable and higher-fidelity replacement for the 78 rpm shellac discs.[4] The first 45 rpm records were monaural, with recordings on both sides of the disc. As stereo recordings became popular in the 1960s, almost all 45 rpm records were produced in stereo by the early 1970s. Columbia, which had released the 33 ⅓ rpm 12-inch vinyl LP in June 1948, also released 33 ⅓ rpm 7-inch vinyl singles in March 1949, but they were soon eclipsed by the RCA Victor 45." https://en.wikipedia.org/wiki/Single_(music)

33s -

"After World War II, two new competing formats came onto the market and gradually replaced the standard 78 rpm: the ​33 1⁄3 rpm (often just referred to as the 33 rpm), and the 45 rpm. The ​33 1⁄3 RPM LP (for "long-play") format was developed by Columbia Records and marketed in June 1948." https://en.wikipedia.org/wiki/Phonograph_record

16s -

"Some recordings, such as books for the blind, were pressed at ​16 2⁄3 rpm. Prestige Records released jazz records in this format in the late 1950s; for example, two of their Miles Davis albums were paired together in this format. " https://en.wikipedia.org/wiki/Phonograph_record


2. The most common are 16 2/3, 33 1/3, 45 and 78 RPM. There were a range of speeds from 60-130 RPM for early discs, which gradually settled on 78.

https://en.wikipedia.org/wiki/Phonograph_record
https://en.wikipedia.org/wiki/LP_record

I hope that helps :D

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