The German clarinettist Theo Jörgensmann (1948) is seen as one of the most important modern improvisers on this instrument. Recordings from 1993 with a quintet, and in duo with the German bass clarinettist Eckard Koltermann. European improvisation music of high-quality!
Sources:
Theo J.: aesthetic direction (Konnex KCD 5054)
German Clarinet Duo (KIP 07)