The Dutch-born Jeroen Thesseling is the bass player for the German death metal band Obscura from Munich since 2007.

Born in 1971, Jeroen learned to play the violin at the age of six. He says that his parents motivated him to start with music. Influenced by rock and metal Jeroen decided in 1985 to switch to the electric bass and in 1988 he started his bass studies at the Hogeschool Enschede conservatory in Holland.

He played with the death metal band Pestilence between 1992 and 1994, released the album Spheres and went on tour through Europe. Between 2003 and 2005 he toured with the flamenco ensemble "El Periquin" and in 2005 he started playing also for the "Ensemble Salazhar".

Jeroen has been playing 6-string Thumb NT basses exclusively since 1993 and concentrated on fretless since 1994. According to him he was influenced by bassist Carles Benavent. Besides the tempered 12-tone scale, Jeroen has been working intensively on the intonation of 72 notes based on micro tonality since 1995. Obscura signed a record deal with Relapse Records in September 2008 and released their second album Cosmogenesis in February 2009. In October 2009 Jeroen rejoined PESTILENCE after a 15-year break, however, he emphasized that he will continue to work with OBSCURA as well. Thesseling is one of the very few bassists in the metal scene playing fretless bass.