Sean Derrick Cooper Marquardt, born in Chicago (USA), now living in Berlin, is a performance artist, musician and composer of experimental music. He developed the "Accidental Guitar" concept and was founding member of "Hildeguard" with musicians
GUIDO MÖBIUS and TOBY BURDON a former member of TEST DEPARTMENT .
He is founding member of the musical projects Accidental Music and "The Return Of The Think Thing , Sean Derrick Cooper Marquardt is also a member of the dance and theatre composer project ( Tradishion), together with musician Paul Hines also a former member of Test DEPARTMENT.

SDCM is also a member of (Electro Sushi) a dj, laptop, film, guitar, project
from Berlin Tacheles, Sean Derrick Cooper Marquardt is active member of (The RADIOACTIVE ENSEMBLE) .

His music has been released so far in Germany, Brasil , England, Mexico , Portugal , Spain , Egypt , Irland Belgium (FF HHH Records und Mandai Distribution) , Japan, Australien, Netherlands, Croatia, Italy , Russia , Ukraine and the USA.