|Studio album by|
|Released||28 February 1971|
|Recorded||October–November 1970 at Olympic Studios, London|
|Label||CBS (UK), Columbia (USA)|
|Soft Machine chronology|
|Christgau's Record Guide||B|
The numeral "4" is the title as shown on the cover in all countries, but a written-out title appears on the spine and label. This was the group's first all-instrumental album, although their previous album Third had almost completed the band's move in this direction toward instrumental jazz, and a complete abandonment of their original self-presentation as a psychedelic pop group, or progressive rock group. It was also the last of their albums to include drummer and founding member Robert Wyatt who afterwards left. He had already recorded a solo album, The End of an Ear (in which he described himself on the cover as an "Out of work pop singer currently on drums with Soft Machine"), and now founded a new group, Matching Mole, whose name was a pun on "Soft Machine" as pronounced in French: "Machine Molle".
Like the previous Soft Machine album, some tracks have the band augmented by additional musicians. These include Mark Charig and Nick Evans, who had been in the septet lineup of late 1969, and Roy Babbington, who would join the band in 1973.
In 1999, Soft Machine albums Fourth and Fifth were re-released together on one CD.
In 2007, Fourth was re-released as part of the series Soft Machine Remastered – The CBS Years 1970–1973.
The booklets of these re-releases contain liner notes written by Mark Powell from Esoteric Recordings about the history of Soft Machine, their musical development and as one of the first relevant bands in the so-called progressive rock scene.
All compositions by Hugh Hopper except where indicated.
- "Virtually Part 1" – 5:16
- "Virtually Part 2" – 7:09
- "Virtually Part 3" – 4:33
- "Virtually Part 4" – 3:23
- Elton Dean – alto saxophone, saxello
- Mike Ratledge – acoustic piano, Hohner Pianet electric piano, Lowrey organ
- Hugh Hopper – bass guitar, fuzz bass
- Robert Wyatt – drums
- Additional personnel
- Roy Babbington – double bass (1, 3, 4, 6)
- Mark Charig – cornet (2, 3, 4)
- Nick Evans – trombone (1, 2, 4)
- Jimmy Hastings – alto flute (6), bass clarinet (1, 6)
- Alan Skidmore – tenor saxophone (1, 6)
- Taylor, Ken. "Soft Machine - Fourth (1971) album review, credits & releases | AllMusic". AllMusic. Retrieved 25 July 2011.
- Neate, Wilson. "Soft Machine - Fifth (1972) album review, credits & releases". AllMusic. Retrieved 6 May 2019.
- Christgau, Robert (1981). "Consumer Guide '70s: S". Christgau's Record Guide: Rock Albums of the Seventies. Ticknor & Fields. ISBN 089919026X. Retrieved 12 March 2019 – via robertchristgau.com.
- "Reviews at Progreviews website". Archived from the original on 19 February 2006. Retrieved 10 February 2006.
- Soft Machine - Fourth (1971) album review by Ken Taylor, credits & releases at AllMusic
- Soft Machine - Fourth (1971) album releases & credits at Discogs
- Soft Machine - Fourth (1971) album credits & user reviews at ProgArchives.com
- Soft Machine - Fourth (1971) album to be listened on Spotify
- Soft Machine - Fourth (1971) album to be listened on YouTube