Asmus Tietchens (born 3 February 1947, Hamburg), who also records under the monikers Hematic Sunsets and Club of Rome, is a German composer of avant-garde music.

Tietchens became interested in experimental music and musique concrète as a child, and began recording sound experiments in 1965 with electronic musical instruments, synthesizers and tape loops. In the 1970s he met producer Okko Bekker, and the two formed a decades-long partnership. Peter Baumann (of Tangerine Dream) heard a recording of Tietchens' music and offered to produce an album; the result was Nachtstücke, Tietchens' 1980 offering on Sky Records. His early recordings feature more accessible synthesized music, but beginning with Formen Letzer Hausmusik, his 1984 release for Nurse With Wound's label United Dairies, he began moving toward more abstract sound collages. He has taught acoustics in Hamburg since 1990.