Formed in Cambridge in 1969 by Tim Souster and Roger Smalley, Intermodulation started out as a four-piece group with the addition of Robin Thompson and Andrew Powell (who soon moved on to other Cambridge projects, including a pre-Chris Cutler Henry Cow). Powell was replaced by Peter Britton, and this incarnation of the group remained for the duration of their existence. Having released a box set of works by Gentle Fire, it felt necessary to do the same with Intermodulation and thus complete the other half of this missing chapter in British experimental music. Intermodulation had quite a different line up than Gentle Fire, most notably with Peter's percussion, Robin on bassoon and soprano sax, and the shared use of VCS3's and electric keyboards. Nonetheless both groups covered similar ground, appeared at the same European festivals, travelled together with Stockhausen to Iran, and they were generally concerned with a similar repertoire of experimental scores. Although Intermodulation released no records during their existence (and Gentle Fire only the one LP), both groups did appear side by side on the recording of Stockhausen's Sternklang. This four-CD set aims to cover a wide range of their work. CD one contains the entirety of their 1971 concert at Ely Cathedral (a six-minute excerpt of which appeared on the Not Necessarily English Music compiled by David Toop). CD two focuses on their BBC recordings including excerpts from two Prom performances, one of which is the famous 1970 Prom which had Soft Machine taking the stage in the second half. CD three features material held in the archives of three German radio stations and the fourth disc consists of one work; "World Music" by Tim Souster, the 72-minute opus written for the four players plus tape. In summary, Intermodulation plays five Stockhausen pieces (four of which are realizations of his intuitive text pieces), two Terry Riley pieces and one by Cardew. They also play two compositions by Tim and one by Roger, as well performing two group improvisations. The set comes with a 48-page booklet detailing the groups history. This is a numbered edition of 500.

1.01. Dorian Mix (Terry Riley)
1.02. Performants
1.03. Material (Cornelius Cardew)
1.04. Aufwärts (Karlheinz Stockhausen)
2.01. Keyboard Study No.2 (Terry Riley)
2.02. Expo for 3 (Karlheinz Stockhausen)
2.03. Zorna (Tim Souster)
2.04. Über die Grenze (Karlheinz Stockhausen)
3.01. Melody Study I (Roger Smalley)
3.02. Wellen (Karlheinz Stockhausen)
3.03. Freies Zusammenspiel
3.04. Abwärts (Karlheinz Stockhausen)
4.01. World Music (Tim Souster)