Guide of the Vinyl formats
The name by format type is based on the physical size of the diameter of the microgroove record.
This is most used in English-speaking countries where the measurement unit of length is the inch. These names also happen to be used in France for vinyl records that come from English-speaking regions. More rarely, sometimes names in approximate centimetres are used in France.
Seven inches (17 cm)
A seven inches, or 7" in short, is a vinyl record measuring 7 inches in diameter, i.e. 17.78 centimetres. This format is usually used for the singles and more specifically for the 45 rpm. More rarely it is used for the max. 45 rpm and in the 1960's and 70's, some albums for children were released in 33 rpm.
Ten inches (25 cm)
A ten inches, or 10" in short, is a vinyl record measuring 10 inches in diameter, i.e. 25.4 centimetres. This format, in vogue up to the early 70's diminished in use later in favour of the 12" (30 cm).
Twelve inches (30 cm)
A twelve inches, or 12" in short, is a vinyl record measuring 12 inches in diameter, i.e. 30.48 centimetres. This format is usually used for albums and more generally for the 33 rpm long play records, it is also used for the 45 and 33 rpm max or even some singles.
78 rpm record
A common mistake is classifying the 78 rpm records as microgroove records. This is incorrect. The word "microgroove" had just been invented at that time to differentiate the new products from the standard records (78 rpm).
Playing records of this type on a standard turntable fitted with a diamond designed for the microgrooves gives a background noise since this stylus tip is too thin compared to the record's groove. In the years 1960 to 1980, it was possible to obtain reversible "sapphires", with one side for the microgrooves and the other for the 78 rpm.
45 rpm record
The records rotating at 45 rpm were invented for the "juke-box" market (which explains the large hole in the centre). They generally have a diameter of 17.5 cm (7 inches) and contain one song on each side. These are the ancestors of the two title CDs (also called CD Singles) and, in addition to the jukebox machines, their main customers were teenagers - over a period spanning the 1960's to the 1990's - who spent a large part of their pocket money there. Only the 45 rpm were compatible with the slot-in record players.
The single features the main song on side A, and a less important or unreleased song meant to complete the 2nd side. By extension, the song itself is called side-B, and many of them did not appear in the corresponding albums. On occasions, the Beatles published the 45 rpm records with two A sides. Some groups from the 60's and 70's released some B-sides nearly 30 years later as Bonus in a re-release of the album in a CD or a compilation. Sometimes, the B-side was the instrumental or karaoke version of the main song.
There are also the 7 inches with 4 titles (super 45 rpm), called EP for "Extended Play"; they are too long to be called singles, but too short to be called an album. These 7 inches generally rotate at 45 revolutions per minute but sometimes they rotate at 33 rpm.
Some Maxi 45 rpm records with 30 cm diameter were published, mainly to contain classical music. In the late 1970s, the Maxi 45 rpm (or maxi-single, super-45 RPM) mainly became standard to contain longer pieces (from 5 to 20 minutes, sometimes more) associated with disco and funk music played in nightclubs. The maxi-45 RPM were also acclaimed by DJs who found them easier to handle, combined with superior sound quality. On these records, we also find versions with additional remixed tracks or unreleased pieces that do not feature on the album (the B-sides).
Some vinyls even have one side in 45 rpm and one side in 33 rpm. We have also seen records that are played from the centre outwards, as is the case today for the CDs. Since sound reproduction is best in grooves furthest from the centre of the record, this feature allows better reproduction of classical music, since it generally goes crescendo, and thus become more complex as the piece advances.
33 rpm record
The records that rotate at 33 revolutions and 1/3 (i.e.: a third of the revolution) per minute generally have a diameter of 30 cm (12 inches), or in more rare cases of 25 cm (10 inches), at the start of the vinyl record's history and more recently for some re-releases and some punk music records. They were developed by engineers at the Columbia Records label in 1948. The 33 rpm of 17 cm (7 inches) are called EP (for "Extended play") and generally contain eight titles. They serve as a support to song albums or to classical music, as well as for original film soundtracks. In the song domain, the 33 rpm record format, lasting from 40 to 60 minutes, is the origin of the album concept, thanks to the LP process (LP for "Long Play").
The 33 rpm also served as support for the maxi singles in Funk, Disco etc. As the sound quality was better than the 45 rpm, many, instead of releasing a 45 rpm in 12", preferred to release a 33 rpm in a 12" with grooves further apart, or else if the long version was over 8 or 10 minutes.
As part of re-mastering, or the CD re-releases in the 1980s and 1990s, some original soundtracks of album were lost. Engineers and assistants then went about searching for masters in order to use them to re-release them as CD. When no master could be found, they then used an original vinyl version in mint condition, to make a re-recording to put it back on CD.
16 rpm record
The records rotating at 16 revolutions per minute did not find large commercial success. They were mainly intended to act as support to spoken texts. These LP records rotate exactly at 16 2/3 rpm, i.e. at half of 33 1/3 rpm. They made their appearance in 1957 and exist in different diameters: 17 cm for language learning (school use), 25 cm for some commercial publications (in France, the Vogue and Ducretet-Thomson brands were published in it), 30 cm for long literary works or plays intended for the blind and the visually impaired.
In this field, in France, the Union of the War Blind released many sets (from 6 to 10 records) with up to 1 hour of recording per side. The specificity of the records included in these sets was that they had a central label printed on one side and, on the other side, a black label with the title of the work written in Braille. In the United States, the company RCA pressed such records. Again in the United States, from 1956 to 1958 the company Columbia pressed 16 rpm records (diameter 17 cm) for its "Highway Hi-Fi phonograph" automobile turntables. These discs were of 40 to 45 minutes duration per side but had to be exclusively played on the car turntable, since the groove, which was twice as narrow, required a special playing head.
Most of the phonograph manufacturers had planned for this 16 rpm speed on their equipment, but due to very low commercial production of these records, this option disappeared in a few years. With regard to analogue sound reproduction, faster the medium rotates (or scrolls), better is the quality especially at high frequencies (treble). From this viewpoint, the 16 rpm records had some trouble convincing knowledgeable music lovers.
In the "Geo" programme broadcast on Arte in December 2010 and dedicated to "Gene Winfield, the mechanic of crazy cars" (http://www.arte.tv/fr/3544738.html) we learn that the company Chrysler fitted some of its cars with a turntable. A collector even said that "Chrysler manufactured its own records" 16 2/3 rpm.