Editing Phonograph record (section)

====Microgroove and vinyl era====
[[File:1959 Seeburg 16 rpm record.jpg|thumb|left|1959 [[Seeburg Corporation|Seeburg]] 16&nbsp;rpm record (label only)]]

Columbia and RCA Victor each pursued their [[R&D]] secretly.<ref name="Popular Science 1949">{{Cite journal |last=Gorman |first=Robert |title=What's What in the Platter Battle |journal=Popular Science |volume=154 |issue=5 |pages=132–133 |date=May 1949 |url=https://books.google.com/books?id=ZiQDAAAAMBAJ&pg=RA1-PA132 |issn=0161-7370 |publisher=Bonnier Corporation}}</ref> 

The commercial rivalry between RCA Victor and Columbia Records led to RCA Victor's introduction of what it had intended to be a competing vinyl format, the 7-inch (175&nbsp;mm) 45&nbsp;rpm disc, with a much larger center hole. For a two-year period from 1948 to 1950, record companies and consumers faced uncertainty over which of these formats would ultimately prevail in what was known as the "War of the Speeds" (see also [[Format war]]). In 1949 Capitol and Decca adopted the new LP format and RCA Victor gave in and issued its first LP in January 1950. The 45&nbsp;rpm size was gaining in popularity, too, and Columbia issued its first 45s in February 1951. By 1954, 200 million 45s had been sold.<ref>Soderbergh, p. 194.</ref>

Eventually the 12-inch (300&nbsp;mm) {{Fraction|33|1|3}}&nbsp;rpm LP prevailed as the dominant format for musical albums, and 10-inch LPs were no longer issued. The last [[Columbia Records]] reissue of any [[Frank Sinatra]] songs on a 10-inch LP record was an album called ''Hall of Fame'', CL 2600, issued on 26 October 1956, containing six songs, one each by [[Tony Bennett]], [[Rosemary Clooney]], [[Johnnie Ray]], [[Frank Sinatra]], [[Doris Day]], and [[Frankie Laine]].<ref name="ReferenceA" />

[[File:45rpm.jpg|thumb|45 rpm vinyl record from 1965]]

The 45&nbsp;rpm discs also came in a variety known as [[extended play]] (EP), which achieved up to 10–15 minutes play at the expense of attenuating (and possibly compressing) the sound to reduce the width required by the groove. EP discs were cheaper to produce and were used in cases where unit sales were likely to be more limited or to reissue LP albums on the smaller format for those people who had only 45&nbsp;rpm players. LP albums could be purchased one EP at a time, with four items per EP, or in a boxed set with three EPs or twelve items. The large center hole on 45s allows easier handling by [[jukebox]] mechanisms. EPs were generally discontinued by the late 1950s in the U.S. as three- and four-speed record players replaced the individual 45 players. One indication of the decline of the 45&nbsp;rpm EP is that the last [[Columbia Records]] reissue of [[Frank Sinatra]] songs on 45&nbsp;rpm EP records, called ''Frank Sinatra'' (Columbia B-2641) was issued on 7 December 1959.<ref name="ReferenceA" />

The [[Seeburg Corporation]] introduced the [[Seeburg 1000|Seeburg Background Music System]] in 1959, using a {{Fraction|16|2|3}}&nbsp;rpm 9-inch record with 2-inch center hole. Each record held 40 minutes of music per side, recorded at 420 grooves per inch.<ref>{{Cite news |last = Biro |first = Nick |title = Seeburg Background Music Move Part of Diversification Program|newspaper=Billboard|location = New York|page=67|date=20 July 1959 }}</ref>

From the mid-1950s through the 1960s, in the U.S. the common home record player or "stereo" (after the introduction of stereo recording) would typically have had these features: a three- or four-speed player (78, 45, {{Fraction|33|1|3}}, and sometimes {{Fraction|16|2|3}}&nbsp;rpm); with changer, a tall spindle that would hold several records and automatically drop a new record on top of the previous one when it had finished playing, a combination cartridge with both 78 and microgroove styli and a way to flip between the two; and some kind of adapter for playing the 45s with their larger center hole. The adapter could be a small solid circle that fit onto the bottom of the spindle (meaning only one 45 could be played at a time) or a larger adapter that fit over the entire spindle, permitting a stack of 45s to be played.<ref name="spindle" />

RCA Victor 45s were also adapted to the smaller spindle of an LP player with a plastic snap-in insert known as a "[[45 rpm adapter]]".<ref name="spindle" /> These inserts were commissioned by RCA president [[David Sarnoff]] and were invented by Thomas Hutchison.{{Citation needed|date=April 2024}}

[[Capacitance Electronic Disc]]s were [[videodisc]]s invented by RCA, based on mechanically tracked ultra-microgrooves (9541 grooves/inch) on a 12-inch conductive vinyl disc.<ref>{{cite web |url=http://www.cedmagic.com/home/cedfaq.html#onethree |title=RCA SelectaVision VideoDisc FAQ |website=Cedmagic.com |access-date=7 May 2015 }}</ref>