33⅓ rpm

Dynaquad (1970 – 1976)

In 1969, Dynaco introduced a system to ‘derive’ surround sound from stereophonic LPs by using a passive electronic circuit called a Hafler Circuit. This was designed by Dave Hafler of Dynaco in the early 1960s and required four speakers in a diamond configuration for derived quadraphonic (2:2:4) sound.

Around 1970, Dynaco introduced the Dynaquad system for encoding matrixed quadraphonic sound (4:2:4). The system was similar to EV Stereo-4 (EV-4) introduced in 1970, and was broadly compatible.

A sampler disc for the Dynaquad system was released in 1971 on the Vanguard Records label, and by this time it was suggested that the four speakers were placed in the four corners of the room rather than the diamond configuration.

Very few records appear to have used Dynaquad encoding. The 1970 eponymous album by The Flame may have used Dynaquad, along with some of the ‘Environments’ series by Syntonic Research. There were also some LPs and 7-inch singles produced by KL Recordings in the mid-1970s.

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Gakken Toy Record Maker (2020 – )

The Toy Record Maker (also called the Easy Record Maker) was designed by Yuri Suzuki and is made by the Japanese Gakken company.

The self-assembly record maker is a small record cutting lathe that uses 5-inch blanks (available in different colours) and records in mono at either 45 or 33⅓ rpm for a recording time of approximately 3 or 4 minutes respectively. The discs themselves are flexible and are clamped onto the turntable to prevent slippage. The record maker can also playback the discs once recorded.

Whilst the device is officially described as a toy and the sound quality is lo-fi, there are discussions and videos available about how to improve the recording through equalisation, cut depth, disc heating, power source and so on.

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Movin Pictures See & Hear Pack (1977 – 1978)

The Movin Pictures player was a combined phonograph and projector aimed at children, and was introduced by Vanity Fair Industries in 1977 for the US market. Each See & Hear pack for use with the player consisted of a 7-inch 33⅓ rpm record, along with a circular picture disc that turned as the record played to project different images. It was similar in concept to the more popular Show’N Tell.

There were three series of See & Hear Packs – Terrytoons in red packs, Nursery Rhymes in blue packs, and Captain Kangaroo in yellow packs.

The Movin Pictures player could project onto its own lid, or on to a wall up to six feet away. It could also play standard 7-inch records at 45 or 33⅓ rpm.

It doesn’t appear to have been very popular, and only around 24 Show & Tell Pack titles were produced in 1977 or 1978.

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8ban / Triple Inchophone records (2004 – 2006, 2019 – )

8ban records are so called because they are 8 cm in diameter (just over three inches). They were introduced for the Japanese market by Bandai in 2004 along with a special battery-powered player and eighty titles were available at launch, including Japanese pop and some Western oldies.

Bandai produced the player for around a year, and in 2005 the band The White Stripes bought up the remaining stock of 400 players to sell as merchandise on their tours, along with 8ban versions of eight of their singles. They called the format Triple Inchophone, referring the 3-inch size, and these records now command a high price.

8ban records are single-sided and can hold up to 4 minutes of music played at 33⅓ rpm. Some records have a small centre hole, while others have a larger hole like a US 45 rpm single, so the 8ban player came with a small adaptor for these. Although the Bandai 8ban player only had one speaker, the records were usually stereophonic. Due to their small size, most standard record players cannot play them.

In 2019 a new 8ban record player was released, the Crosley RSD3, along with 20 new titles for Record Store Day.

As of April 2019, there have been 116 titles produced on 8ban records.

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Audiodisc (1938 – )

Audiodisc is a brand of lacquer disc (sometime known as acetate or instantaneous disc) that was introduced to the US market in 1938 by Audio Devices, Inc. They were made under license from the Pyral company in France that had invented the nitrocellulose lacquer-coated disc in 1934 and that also licensed the process to EMI for their Emidisc brand in the UK.

Audiodiscs were mostly used for home recordings but were sometimes used by recording studios to give to clients to hear at home what they had recorded in the studio. As they were mostly used on simpler home recording devices, they had an extra (sometimes three extra) drive pin holes to prevent slippage – commercial disc cutting machines such as those used to create master discs would have used a vacuum to hold the disc in place. Like professional lacquer discs, the core of an Audiodisc is made of aluminium, making the disc much heavier than a standard shellac or vinyl disc.

Audiodiscs are likely to have handwritten information on the label, and can be difficult to date although various designs of label have been used over the years that may help with dating. They were available in different sizes, including 7, 10 and 12-inches in diameter. The lacquer coating wears much quicker than standard shellac or vinyl records, and a chipped stylus can damage the disc in one play.

Audio Devices, Inc. was sold to Capital Records in 1972 who sold it off in the late 1980s at which point it became the Apollo Masters Corporation. Apollo are still producing lacquer discs under the Audiodisc brand as of 2019.

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Matrix H (1977 – 1978)

Matrix H was a matrix quadraphonic audio system devised by the BBC in the mid-1970s and first used in 1977. It was one of a number of systems tested by the BBC, lettered from A to H.

One of the requirements was that it must be compatible with mono and suitable for radio transmission via FM.

Some radio programmes were broadcast in Matrix H, including live broadcasts from the 1977 BBC Proms and some session recordings by bands on Radio 1. This was despite very few people having access to decoders, so some public demonstrations were held. The experimental radio broadcasts lasted until 1978.

No recorded music was officially released, but a handful of 12-inch LPs were released that did use Matrix H but were labelled as stereo.

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Trimicron LP (early 1970s – mid 1970s)

Trimicron records were introduced by the French company MDR (Magnetic Disc Recording) around the early 1970s and offered up to triple the standard duration (triple durée) of a standard 12-inch LP, meaning up to 60 minutes playing time per side. It did this using a technique of removing the gap between the groove walls. Whilst these records could still be played on a good-quality standard turntable at 33 ⅓ rpm, and still offered stereo, they provided lower volume than other records and a reduced dynamic range.

Around 30 titles were released using the Trimicron format, and all of these were classical pieces that benefited from the longer playing time before the music was interrupted by the need to turn the record over.

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Cook Binaural record (1952 – 1958)

Cook Binaural records were the very first form of 12-inch stereo LP, predating other stereo phonograph records by five years. The Cook binaural system used two separate sets of grooves, played with a tonearm that had two cartridges exactly 1 11/16-inches apart. At the outer edge of the disc was a band of grooves for the left channel, and then a band of grooves towards the centre of the disc for the right channel.

Emory Cook, the inventor of the binaural record, was aware of the EMI system demonstrated in 1933 (and that later was adapted for single-groove stereophonic records) but he felt that the frequency range would be compromised by the technology of the time so instead went for a dual-groove system.

A number of recordings were made and released using the Cook binaural system, but they mainly appealed to audiophiles willing to spend the money to buy new equipment; as well as the dual pick-ups, they would need new pre-amps, amplifiers and speakers.

Due to the extra space taken up by having two sets of grooves, the amount of music that could be accommodated on each side of the disc was reduced. Cook Records could also release monophonic versions of the their binaural records on 10-inch LPs since much less space was required.

Stereo LPs using the Westrex single-groove system began to be released in 1957, and by 1958, Cook Records had also begun producing single-groove stereo records.

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EV Stereo-4 (1970 – 1975)

The EV Stereo-4 system (also known as EV-4) was a matrix quadraphonic format, developed by Leonard Feldman and Jon Fixler in 1970 and taken up by Electro-Voice as the first commercial quadraphonic system for vinyl records.

A handful of record labels used the system, including Ovation, Project 3 and Quad-Spectrum, and RadioShack sold compatible decoders and systems in the US.

EV Stereo-4 emphasises front (left to right) and front-to-rear separation, but there is less separation between the two rear channels.

In 1973 Electro-Voice introduced a decoder that could also play SQ and QS quadraphonic records with good results, but despite this Stereo-4 was pushed out of the market by these other systems and nothing appears to have been released on EV Stereo-4 after 1975.

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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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