Twelve-inch single

The twelve-inch single (often written as 12-inch or 12") is a type of vinyl (polyvinyl chloride or PVC) gramophone record that has wider groove spacing and shorter playing time with a "single" or a few related sound tracks on each surface, compared to LPs (long play) which have several songs on each side. It is named for its 12-inch (300 mm) diameter that was intended for LPs. This technical adaptation allows for louder levels to be cut on the disc by the mastering engineer, which in turn gives a wider dynamic range, and thus better sound quality. This record type, which is claimed to have been accidentally discovered by Tom Moulton, is commonly used in disco and dance music genres, where DJs use them to play in clubs. They are played at either 33+1⁄3 or 45 rpm. The conventional 7-inch single usually holds three or four minutes of music at full volume. The 12-inch LP sacrifices volume for extended playing time.

Twelve-inch singles have much shorter playing time than full-length LPs, and thus require fewer grooves per inch. This extra space permits a broader dynamic range or louder recording level as the grooves' excursions (i.e., the width of the groove waves and distance traveled from side to side by the turntable stylus) can be much greater in amplitude, especially in the bass frequencies important for dance music. Many record companies in the 1970s began producing 12-inch (30 cm) singles at 33+1⁄3 rpm, although 45 rpm gives better treble response.

Gramophone records had been introduced in the latter portion of the 19th century, with several pioneers involved in sound reproduction development such as Thomas Edison and Emilie Berliner. Berliner along with Eldridge R. Johnson merged their efforts within the industry to form the Victor Talking Machine Company in New Jersey, USA and perfected the use of 5 and 7-inch rotating shellac discs for sound replay from 1889, with 10-inch records appearing in 1901. In 1903 12-inch discs were introduced by Victor, on their Deluxe label, these able to play for up to four minutes, increasing the available length of a song or speech on the smaller formats. These first 12-inch releases were all by the Victor Grand Concert Band, led by Frederick W. Hager. During the 1910s discs became the standard sound reproduction format, although the speeds used could vary between manufacturers until 78 rpm became the norm from around 1925. An album would consist of several of these single discs packaged together. These brittle shellac discs remained a popular medium through the first attempt to introduce vinyl records in 1931, the subsequent move towards microgroove formats from 1948, and would survive until the early 1960s.

In August 1931, RCA Victor launched the first commercially available vinyl long-playing record, marketed under their Program Transcription series. These revolutionary discs were designed for playback at 33¹⁄₃ rpm (the speed first used on 16‑inch Vitaphone soundtrack discs from 1926) and pressed on ten and twelve-inch diameter flexible Victrolac discs, using a polyvinyl chloride (PVC) compound called vinylite which was licensed from Union Carbide. It was marketed initially as being more robust than shellac, with a duration of up to twenty minutes playing time per side. The first twelve-inch LP (containing only one track per side), was Beethoven's Symphony No. 5 In C Minor by the Philadelphia Orchestra conducted by Leopold Stokowski. RCA's early introduction of a long-play disc was a commercial failure for several reasons including the lack of affordable, reliable consumer playback equipment and consumer wariness during the Great Depression. Because of financial hardships that plagued the recording industry during that period (and RCA's own parched revenues), Victor's long-playing records were discontinued for public sale by early 1933.

However, vinyl continued to be used, notably with broadcasters, on larger 16‑inch radio transcription discs, and later with the V-Disc program that sent records overseas to US troops during World War II to help boost morale. Vinyl as a material for records sold to the public was reintroduced after World War II, first for 78s in 1945 (the Bolshoi Theatre Orchestra and Chorus's Prince Igor a 12‑inch 5-record set from Asch Recordings catalog number M-800), with 12‑inch 33¹⁄₃ rpm LPs (with a narrower "microgroove")) and 7‑inch 45 rpm singles being marketed by Columbia Records and RCA Victor respectively in 1948 and 1949. Intriguingly, although there is a scientific basis behind 45 rpm being an ideal speed for sound quality which was touted by RCA, conveniently the 45 rpm number can also be derived by subtracting 33 from 78. 12-inch records would be reported in the press from the 1940s demonstrating usage not just for music but commercial and other reasons such as interviews, along with general manufacturing and public use reports and even children's records using the format.

Longer tracks could be accommodated on each side of the 12‑inch disc, or shorter but more numerous tracks per side. Indeed, the first 12‑inch vinyl album in 1948, Mendelssohn's Concerto in E Minor, featured only three tracks (the 11-minute first movement on side one, and the second and third movements on side two, together adding another 14 minutes) and was extended play (EP) in appearance, rather than a typical album with multiple tracks each being on average 2–4 minutes such as the first 10‑inch vinyl album, a reissue of The Voice of Frank Sinatra. While one to two short playing songs being sold to the public were more suited for the seven‑inch 45 rpm record, the LP could be anything from 1 track per side, and if in that simplistic configuration it technically could be classed as a twelve‑inch single. Over the ensuing years some works, particularly in the classical and jazz genres, and the relatively few tracks on an occasional album could blur the boundaries of what would become considered a twelve‑inch single, an EP and an album, with the price, catalogue number, any stylistic aims of the performing artist, marketing by the record label, as well as record industry sales charts rules regulating the differences between formats.

The gramophone records cut especially for dance-floor DJs came into existence with the advent of recorded Jamaican mento music in the 1950s. By at least 1956 it was already standard practice by Jamaican sound systems owners to give their "selecter" DJs acetate or flexi disc dubs of exclusive mento and Jamaican rhythm and blues recordings before they were issued commercially.

In March 1970, Cycle/Ampex Records test-marketed a twelve-inch single by jazz-pop guitarist Buddy Fite, featuring "Glad Rag Doll" backed with "For Once in My Life", both from his self-titled debut album issued in 1969. Subtitled 'The world's first 12-inch single!', the experiment aimed to energize the struggling singles market, offering a new option for consumers who had stopped buying traditional singles. The record was pressed at 33 rpm, with identical run times to the seven-inch 45 rpm pressing of the single and album, but with a large runoff area. Several hundred copies were made available for sale for 98 cents each at two Tower Records stores in California. Ampex also serviced a promo for Canadian act Young titled "Goin' In The Country" during 1971, the accompanying promotional note proclaiming the record as 'the biggest Canadian single ever.'.