Karn contributed to recordings by other artists, playing bass guitar on Bill Nelson's "Chimera" mini-LP, bass guitar and saxophone on Gary Numan's 1981 album "Dance", and also played with Kate Bush and Joan Armatrading. In the 1990s he started the Medium Productions label along with Steve Jansen and Richard Barbieri, two of his fellow former Japan-members. and Debi Zornes (label management and artist co-ordination). In 2006, the MK Music imprint was established, by Karn, Debi Zornes and Mike Trenery — and beginning with 2006's "Three Part Species", all releases, including the autobiography, have the MK Music logo on them.