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The earliest commercially released recordings, (circa the 1890's) were issued on the wax cylinder format and had a play time of around 2 minutes. Laterally recorded disc's of the same period were capable of a play time of around 3 minutes. Ultimately, the cylinder format was extended to 4 minutes (Edison Blue Amberols are an example) while the disc format became capable of 3.5 to 5 minutes in total play time depending on record diameter (10 or 12 inch).
As early as 1926, the Edison company developed and introduced a long playing 80 RPM record. These vertically cut recordings achieved 24 minutes of play time by increasing the pitch of the groove to 450 per inch. However, the heavy pickup coupled with the very fragile groove wall quickly obsoleted this very fragile technology and very few recordings were issued in this format.
RCA Victor viewed the long playing record problem a little differently. They introduced a line of recordings called their "Program Transcription" series which achieved longer playing time by reducing the speed to 33 1/3 RPM. These records had the same groove pitch as their 78 counterparts, but due to the slow speed, exhibited a significant reduction in frequency response despite their 10 minute per side play time. Ultimately, this technology did not take off because of the lack of adequate audio quality.
In the spring of 1948, Columbia introduced the 33 1/3 RPM microgroove LP as a result of the efforts of Messrs Goldmark and Backmann of their research staff. These recordings not only ran at a slower speed, but also used a tighter pitch compared to the earlier Victor Program Transcriptions. Because of the tighter pitch (smaller groove) greater frequency response could be achieved while producing a play time of around 20 minutes using a 12 inch diameter disc. The fine pitch of 190 to 225 grooves per inch coupled with its 1 mil width facilitated both the need for higher audio performance* while extending the systems play time. Also, a lower noise playing surface was employed compared to the 78 RPM shellac technology. Black Vinylite was used for the media surface.
Because this new record technology utilized a combination of a slower speed, a smaller groove wall width and a softer playing surface, they needed to develop a compatible record player for this format utilizing a light pickup having a permanent stylus as opposed to the replaceable "steel needle." That job was assigned to the Philco Radio and Television Company of Philadelphia.
Despite RCA Victors investment in the 45 RPM technology**, they joined in and started issueing LP's in February of 1950. Similarly, Columbia commenced the production of 45 RPM records 1 year later to the month.
Both formats co-existed successfully throughout their lifetime, with the 33 1/3 RPM LP addressing the needs of the album market while the 7 inch 45 RPM reccord addressed the needs of the single market.
*Note 1: An analysis of record frequency response as a function of tangential velocity and stylus size can be found at the following link:
http://www.diamondcut.com/vforum/showthread.php?t=2152
**Note 2: More information can be found on the evolution of the 45 RPM Record format at the following link:
http://www.diamondcut.com/vforum/sho...RPM+RCA+Victor
keywords: Vinyl LP History, Columbia LP History, LP Record History, RCA 45 RPM History, Early LP History, RCA Program Transcription LP
As early as 1926, the Edison company developed and introduced a long playing 80 RPM record. These vertically cut recordings achieved 24 minutes of play time by increasing the pitch of the groove to 450 per inch. However, the heavy pickup coupled with the very fragile groove wall quickly obsoleted this very fragile technology and very few recordings were issued in this format.
RCA Victor viewed the long playing record problem a little differently. They introduced a line of recordings called their "Program Transcription" series which achieved longer playing time by reducing the speed to 33 1/3 RPM. These records had the same groove pitch as their 78 counterparts, but due to the slow speed, exhibited a significant reduction in frequency response despite their 10 minute per side play time. Ultimately, this technology did not take off because of the lack of adequate audio quality.
In the spring of 1948, Columbia introduced the 33 1/3 RPM microgroove LP as a result of the efforts of Messrs Goldmark and Backmann of their research staff. These recordings not only ran at a slower speed, but also used a tighter pitch compared to the earlier Victor Program Transcriptions. Because of the tighter pitch (smaller groove) greater frequency response could be achieved while producing a play time of around 20 minutes using a 12 inch diameter disc. The fine pitch of 190 to 225 grooves per inch coupled with its 1 mil width facilitated both the need for higher audio performance* while extending the systems play time. Also, a lower noise playing surface was employed compared to the 78 RPM shellac technology. Black Vinylite was used for the media surface.
Because this new record technology utilized a combination of a slower speed, a smaller groove wall width and a softer playing surface, they needed to develop a compatible record player for this format utilizing a light pickup having a permanent stylus as opposed to the replaceable "steel needle." That job was assigned to the Philco Radio and Television Company of Philadelphia.
Despite RCA Victors investment in the 45 RPM technology**, they joined in and started issueing LP's in February of 1950. Similarly, Columbia commenced the production of 45 RPM records 1 year later to the month.
Both formats co-existed successfully throughout their lifetime, with the 33 1/3 RPM LP addressing the needs of the album market while the 7 inch 45 RPM reccord addressed the needs of the single market.
*Note 1: An analysis of record frequency response as a function of tangential velocity and stylus size can be found at the following link:
http://www.diamondcut.com/vforum/showthread.php?t=2152
**Note 2: More information can be found on the evolution of the 45 RPM Record format at the following link:
http://www.diamondcut.com/vforum/sho...RPM+RCA+Victor
keywords: Vinyl LP History, Columbia LP History, LP Record History, RCA 45 RPM History, Early LP History, RCA Program Transcription LP