While playing in the jazz-rock group Agitation Free, he and his mentor, Swiss avant-garde composer Thomas Kessler, set up a sound studio and began teaching courses in improvisation, laying the groundwork for what would become the Berlin School of Electronic Music. Through the school, Franke met Edgar Froese and Peter Baumann, joining them in Tangerine Dream in 1970; he remained with the group for nearly two decades, during that time greatly expanding the parameters of electronic music through his contributions to landmark records including Zeit, Atem, and Phaedra as well as influential film soundtracks like Sorcerer, Risky Business, and Legend. One of the first musicians to explore the full creative scope of the synthesizer, Franke proved particularly innovative in employing sequencers as percussion instruments, forging the dense, throbbing sound which became Tangerine Dream's trademark during the mid- to late '70s. He left the group in 1988 to mount a solo career, settling in Los Angeles two years later to pursue film work; in 1991, in addition to forming the Berlin Symphonic Film Orchestra (BSFO), Franke issued his debut solo album, Pacific Coast Highway. In 1993, he founded his own label, Sonic Images, subsequently releasing several collections of his music for the syndicated sci-fi series Babylon 5 as well as his continuing solo recordings. Three years later, Franke released Perry Rhodan Pax Terra which was followed in 1999 by Epic. ~ Jason Ankeny