Tagged: disc

In computing, the term disc is normally used for optical media, whereas disk (or diskette) is normally used when describing magnetic storage media (such as floppy disks).

Disc is also generally used to describe phonograph records.

Recordon (1948 – mid 1950s)

The Recordon was an office dictation system using 9-inch paper disc with a magnetic coating. It was introduced by the UK company Thermionic Products in 1948 with the Recordon TP503 machine, made under license by the Brush Development Company of the USA that produced the Mail-A-Voice system.

The Recordon Recording Disc had fold lines printed on it, and could be folded for mailing. The system was fairly low fidelity, but was adequate for dictation purposes and as the recording runs from the centre to the outside of the disc, quality improves. Discs could be erased for re-use.

A couple of further models of the Recordon were produced, but in the mid-1950s Thermionic switched to the Agavox system.

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8⅓ rpm flexi-discs (early 1970s – 2001)

The National Library Service for the Blind and Physically Handicapped (NLS/BPH) began distributing magazines and books on flexible discs running at 8⅓ rpm in the early 1970s in the US. Machines capable of playing this very slow speed had already been made available a number of years previously when model AE-1 was introduced in 1965, and existing machines were also converted by volunteers. Standard ‘rigid’ records running at 8⅓ rpm had been available via the NLS/BPH since 1969.

Magazine titles available included Readers Digest, National Geographic, Sports Illustrated, and U.S. News & World Report.

The flexi-discs were 9-inches in diameter and had Braille centre labels. They also had narrower grooves than a standard record, so a finer stylus is required to avoid damage. The use of a slow speed and fine grooves allowed very long playing times, but lower fidelity. The discs could be produced quickly and cheaply, meaning audio magazines could be distributed as soon as possible after the print copy. Their success meant the NLS/BPH stopped using rigid records by the late 1980s.

After 1994, audio magazines on flexible disc began to be phased out in favour of Compact Cassettes, and the final discs were sent out in 2001.

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16⅔ rpm LP (Long Play) 12 inch record (early 1950 – early 1970s)

Whilst the vast majority of Long Play records were played at 33⅓ rpm, a few records were made to be played at half that speed, 16⅔ rpm (usually listed as 16 rpm). Many of these were spoken word, since the slow speed meant lower fidelity reproduction, but despite this there were a few music releases, mainly from South Africa.

Even though 16 rpm records were rare even at the time, many record decks of the 1950s, 1960s and even into the 1970s came with a 16 rpm speed setting.

The 16⅔ rpm speed was also used for the short-lived in-car Highway Hi-Fi system of 1956 using 7-inch discs, and for the Seeburg Background Music System of 1959 using 9-inch disks.

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Stereophonic LP (Long Play) 12 inch record (1957 – )

The current system for creating stereophonic (2 channel) phonograph discs date back to 1933 when Alan Blumlein, a senior sound engineer at EMI in London, demonstrated a single-groove system in which the stylus moves both horizontally and vertically.

When the 12-inch Long Play record was launched in 1948, it was initially monophonic, and it wasn’t until 1957 that stereophonic LPs were released, by now using a refined version of the EMI system developed by Westrex (a division of Western Electric) called Westrex 45/45 in which each channel drives the cutting head at a 45 degree angle to the vertical.

In late 1957, Audio Fidelity Records and Bel Canto in the US released demonstration stereo LPs, with the the Bel Canto release on multicoloured vinyl. The first mass-produced stereophonic LPs were released in early 1958.

Mono LPs continued to be released alongside stereo LPs for the next ten years or so with major labels ceasing production in 1968, but 7-inch singles continued to be mono for longer, into the 1970s in some cases.

Stereo records produced using the Westrex system played well on a mono record player, and mono records could be played on a stereo system.

In the 1970s, quadraphonic (4 channel) LPs were produced, but were not a great success partly because there were several competing and incompatible systems.

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Fujifilm PhotoDisc CD-R (2004 – )

Launched in 2004, The Fujifilm PhotoDisc CD-R is essentially a standard CD-R disc with a black substrate layer that claims to protect the data from ultra-violet and solar radiation. It also uses a different dye (phthalocyanine rather than the usual cyanine) in the recording layer, which should offer more resistance to heat and sunlight.

Although they are reported to be very reliable, for archival purposes gold archival CD-R discs are probably better.

Despite the name, the discs can be used for any purpose that a standard CD-R can be used for, and don’t just store photos.

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MovieCD (1997 – late 1990s)

MovieCD was a CD-ROM format for video, introduced by Sirius Publishing Inc. in early 1997, that allowed people to view full-length movies on their Windows PC or laptop using a standard CD-ROM drive.

MovieCDs could be played on PCs running Windows 3.1 and Windows 95 without the need for any additional hardware or software, and the PC hardware requirements were fairly modest. The necessary software and the MotionPixels codec were on the discs themselves and installed automatically.

Each disc could hold up to 45 minutes of video, so two or sometimes three discs were necessary for longer films. The resolution was 320×236 pixels, and the format promised ‘near-TV quality’ images (though of course, the format could only be played on a PC – there were no set-top MovieCD players available).

Over 100 titles were available on the MovieCD format including anime, music concerts and feature films. It competed with Video CD and the newly launched DVD-Video, and no version of MovieCD was developed for versions of Windows beyond Windows 95. It was not a commercial success and disappeared after a few years.

Using the discs on a post-Windows 98 system can cause problems with other video and audio software.

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UHQCD (Ultimate High Quality Compact Disc) (2015 – )

UHQCD is a type of audio Compact Disc introduced by Memory-Tech in Japan in 2015, and is a development of the HQCD (High Quality Compact Disc) introduced six years previously. UHQCD discs conform to Red Book standards and are playable in any audio CD player. They don’t contain any more audio information than a standard CD, but it is claimed that a higher-quality manufacturing process and higher quality materials in the reflective layer produces higher precision audio reproduction.

A photopolymer is used instead of standard polycarbonate, since in their liquid state photopolymers achieve better replication of the pits on the CD stamper.

As of 2017, there were over 900 titles available on UHQCD.

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Blu-spec CD (2008 – )

The Blu-spec CD was introduced in 2008 by Sony, and is a Red Book-compliant audio Compact Disc, so is playable on all audio Compact Disc players. Sony launched with 60 titles on Blu-spec CD.

Its name is derived from the shorter-wavelength blue laser used to create the master copy, which is claimed to produced more precise pits to reduce distortion due to reading errors, along with a new polymer polycarbonate developed for the Blu-ray Disc.

In 2012, a newer version called Blu-spec CD2 (or BSCD2) was introduced that claimed to have a more precise cutting machine and master discs made from silicon wafers. Sony called it Phase Transition Mastering.

Due to existing limitations of Compact Disc Digital Audio, it is debatable whether Blu-spec CDs offer better sound quality as there is no extra information stored on the disc.

As of 2017, new titles are still being released on both formats.

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Little LP (1961 – 1975)

The Little LP (also known as a Jukebox EP) was a 7-inch vinyl record with up to three songs on each side, that played at 33 ⅓ rpm in stereo, and had a small centre hole. They were first introduced by Cadence Records in late 1961, though the Cadence version was in mono and was not designed for jukeboxes.

The Little LP was not successful in the retail market, but it was picked up by Seeburg for use in their new jukebox, introduced in September 1962. The Seeburg version of the Little LP was in stereo, came with title strips, and had a colour cover for display in the jukebox. A number of record companies signed up, mostly easy listening and classical labels, and by 1963 there were 233 titles available with over 1,000 by 1966. Little LPs were also made for other jukebox manufacturers such as Wurlitzer and ATI.

Little LPs were essentially cut-down versions of the full 12-inch LP, and shared the same artwork. Record companies saw the potential of promoting the full LP version by having a selection of tracks available to hear, and the cover on display, in places where adult listeners gathered.

However by 1969, output of Little LPs had dropped sharply. A couple of small manufacturers revived the format in the early 1970s, but only a few titles per year were released in the period 1970-1975. Seeburg introduced new jukeboxes that didn’t play Little LPs in 1971, and the introduction of quadraphonic Little LPs didn’t make any difference as there were very few quadraphonic jukeboxes to play them on.

There were no new titles on the Little LP format for jukeboxes in 1976, but a few Little LPs have been released for the retail market as specialty items since then.

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Minimax Compact Disc (1990s – )

Minimax Compact Discs are generally CD singles which consist of a 3-inch playing area (equivalent to the mini CD single) surrounded by an area of translucent plastic (either clear or coloured) to make them full-size Compact Discs. The playable part of the disc conforms to Red Book standards.

On a normal Compact Disc, the reflective layer would continue to the edge of the disc, even if there was not enough music to fill it.

Because of the small playing area, minimax CDs can only hold a limited playing time (about 24 minutes maximum) and so have only been used for music singles or EPs.

They are very uncommon, presumably because of the extra expense in manufacturing them over a standard 5-inch CD single, but have been used for special edition singles, in much the same way as coloured vinyl records. It could be argued that the holographic CD is a form of minimax CD, as it is also formed of a mini CD single inside a larger area of plastic containing the holographic design.

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