Tagged: 33⅓ rpm

The speed of rotation of some formats of phonograph disc

LP (Long Play) 12 inch record (1948 – )

The LP (Long Play) record is an audio format for phonograph records, introduced by Columbia Records in 1948 and still in use today.

LP records are made of vinyl (either virgin or recycled) and together with a playing speed of 33⅓ rpm and the use of microgrooves, allow for a playing time of around 45 minutes. Previously, 78 rpm records had a playing time of just around 3-4 minutes per side, so an ‘album’ of records was sold as a set, and this name continued to describe a collection of songs on a single disc.

Each side of an LP contains a single continuous groove, with an average length of 460 m.

LP records are generally 12 inches in diameter, but 10 inch LPs have also been produced at different times. The amount of vinyl in an LP is generally 130 g, but some records were produced with less (sometimes as little as 90 g). Modern high-fidelity LPs tend to use more, such as 180 g. Generally LPs are pressed on black vinyl, but coloured vinyl and picture discs (with a card sandwiched between two clear sides of vinyl) have been produced, as have shaped vinyl and even neon vinyl.

By as early as 1952, LPs represented 16.7% of unit sales, rising to 24.4% in 1958 (by then, most of the remainder was 45 rpm singles, 78 rpm only representing 2.1%).

Stereo sound was introduced in 1958, and quadraphonic records were sold in the 1970s for a time.

The LP had no serious competitors for long-playing recordings until the 1970s when the Compact Cassette improved in quality, and then in the 1980s with the introduction of the Compact Disc. LPs ceased to be a mainstream format in the early 1990s, but continue to be produced in small but increasing numbers.

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Preservation / Migration

Show’N Tell (1964 – 1980s)

The Show’N Tell was a combination record player and filmstrip viewer for children.

A 7-inch 33⅓rpm record was played on the record player that sat on top of the Show’N Tell player, while images from a strip of 16mm colour film in a rigid plastic holder were shown on the viewing screen at the front. There were 15 images in total on the filmstrip, and the programme lasted for around 4 minutes, with the images automatically advancing as the record played.

The record and filmstrip sets were called Picturesound programmes, and many different programmes were licensed for the Show’N Tell system. By 1965, 140 programmes were available.

General Electric manufactured the Show’N Tell from 1964 until the 1970s, and then CBS Toys manufactured it from the 1970s to the 1980s. The player was redesigned and CBS Toys sold it as the ‘Show ‘n Tell Phono-Viewer’. Picturesound programmes were released under the ‘Child Guidance’ and ‘Gabriel’ labels. The redesigned model could still play ordinary records, but only had two speeds (33⅓, or 45rpm) as opposed to the older version’s four speeds (16, 33⅓, 45, and 78rpm).

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Americom 8mm Home Movies (1965 – late-1960s)

Americom 8mm Home Movies were first released in 1965 and consisted of a 200 or 400 foot reel of standard 8mm film and an accompanying soundtrack on an 8-inch flexi disc.

The idea was that this enabled viewers with silent 8mm film projectors to play the accompanying soundtrack on a record player. Synchronising the film and soundtrack was tricky, and the instructions explained how to do this which involved threading the film until a frame with black dots appeared, starting the record and waiting for the instruction to ‘start projector on tone’.

If the projector or record player were not running at the correct speed (18 frames per second for the projector, 33⅓ rpm for the record player) then they would gradually become out of sync.

Titles included various Popeye cartoons, and excerpts from Laurel and Hardy films, as well as excerpts from films such as Horror Of Dracula and Curse Of Frankenstein.

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VinylDisc (2007 – )

VinylDisc (also known as vinyl CD) is a hybrid Compact Disc and vinyl phonograph record, developed in Germany by Optical Media Production and first released in 2007.

The CD side is a standard full-length CD, and the vinyl side is a 33⅓ rpm record that can play up to 3.5 minutes of audio on a regular phonograph, although the small size means the vinyl side won’t play on automatic or semi-automatic turntables.

Around 50 or so singles and albums have been released on VinylDisc.

VinylDiscs come with a small centre spindle adapter that can is removed to play the disc in a Compact Disc player.

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PocketDisc (1967 – 1969)

PocketDiscs were 4-inch, 33⅓ rpm, flexible phonograph records introduced by Americom. Americom also produced a portable player for the PocketDisc, called The Music Swinger, that allowed the discs to be played in any position (PocketDiscs could also be played on a manual phonograph).

Unlike the similar Hip Pocket Records, PocketDiscs could be purchased through special vending machines. Americom teamed up with around 28 record labels, and releases on PocketDisc were made simultaneously with the release of the 7-inch single version. Releases on Hip Pocket Records were not current releases.

Americom also teamed up with Apple records and released PocketDiscs with Beatles songs as well as songs from other artists under the Apple label such as the Iveys and Billy Preston. For this reason, some Americom PocketDisc releases are highly collectible, selling for up to £900 for titles such as the Beatles’ Yellow Submarine.

Due to the limited capacity of PocketDiscs (3.5 minutes), some longer songs such as The Beatles’ Hey Jude could not be played in their entirety.

Both Hip Pocket Records and Pocket Discs were marketed for their portability, and the ability to send them through the post or keep in a pocket without damage.

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Electrical Transcription Disc (late 1920s – 1980s)

An Electrical Transcription Disc was a type of phonograph record intended for, or recorded from, a radio broadcast. Their use for this purpose persisted long after the advent of magnetic tape recording because it was cheaper to produce master disc and press 100 identical high-quality discs than to make 100 copies on tape.

They were most commonly 16 inches in diameter and played at 33⅓ rpm, although very early radio programmes (circa 1928-1931) were on sets of 12 inch or even 10 inch diameter 78 rpm discs, and some later (circa 1960-1985) ones were distributed on 12 inch diameter 33⅓ rpm discs. Although the earliest transcription discs were pressed in shellac, in the mid-1930s quieter vinyl compounds were substituted.

Standard 16 inch transcription discs of the 1930s and 1940s usually held about 15 minutes of audio on each side, but this was occasionally pushed to as much as 20 minutes. Unlike ordinary records, some were recorded inside out, with the start of the recording near the label and the end near the edge of the disc. The label usually noted whether the disc was ‘outside start’ or ‘inside start’. Beginning in the mid-1950s, some transcription discs started employing microgroove discs, allowing 30 minutes to fit comfortably on each side of a 16 inch disc.

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Cardboard record (1940s – 1980s)

Cardboard recordCardboard records were a type of phonograph record made of plastic-coated card, similar to Gramophone postcards. They had poor audio quality compared with standard vinyl phonograph discs, and tended to warp easily.

They were often used in promotional campaigns and were intended to be played once or twice. A number were pressed into cereal packets, including songs by groups as the Archies, the Monkees and the Jackson 5. They could also be inserted into magazines, or distributed as greetings cards.

The first examples appeared in the 1940s and were played at 78 rpm. Later versions were 45 or 33⅓ rpm.

They continued to be made well into the 1980s.

Floppy ROM (1977 – mid 1980s)

A floppy ROM is a flexi-disc vinyl record with computer code in audio form.

The first floppy ROM was published in the May 1977 issue of Interface Age and took the form of a 33⅓ RPM flexi-disc with 6 minutes of ‘Kansas City’ standard computer code.

It was recommend that the audio be recorded onto a cassette and then played back to load the programme.

Although never common, the floppy ROM was used into the 1980s to distribute software through some computer magazines.

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10-inch LP (1948 – 1980s)

The 10-inch Long-Play (LP) record is a variation on the 12-inch LP and was introduced at the same time by Columbia Records in 1948.

The 10-inch LP provided around 14 minutes of playing time per side (compared to around 23 minutes on the 12-inch version) at 33⅓ rpm.

The 12-inch format was initially used for higher-priced classical recordings and Broadway shows, while popular music appeared on 10-inch records. By the mid-1950s, this changed and the 10-inch LP version lost out.

10-inch LPs would reappear as mini-albums in the late 1970s and early 1980s in the US and Australia as a marketing alternative.


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12-inch single (1973 – )

The 12-inch (30 cm) single is a phonograph audio format played at 33⅓ or 45 rpm, with wider groove spacing than other records allowing greater dynamic range and volume.

The first 12-inch single is claimed to be ‘Straight from my heart’ by Swamp Dogg in 1973. This was a promotional copy of the 7-inch single, intended for DJs, and the B side was blank.

The first commercial 12-inch single release was in 1976 and was ‘Ten Percent’ by Double Exposure.

The 12-inch single was popular for disco music, and as well as the better dynamic range, the wider groove spacing assisted DJs in locating the approximate area of the ‘breaks’ on the disc’s surface.

Many record companies began producing 12-inch singles at 33⅓ rpm, as the slower speed enhances the bass on the record. However, 45 rpm gives better treble response and was used on many 12-inch singles, especially in the UK.

Increasingly in the 1980s, many pop and even rock artists released 12-inch singles that included longer, extended, or remixed versions of the actual track being promoted by the single. New Order’s Blue Monday, released in 1983, became the biggest-selling 12-inch single ever.

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