Jeroen Paul Thesseling

Thesseling began studying bass in 1988 at the ArtEZ School of Music in Enschede, Netherlands. During the period 1992-1994, he was a member of Pestilence, with whom he recorded the jazz/fusion-influenced album Spheres. In 1995 Jeroen started to study microtonality, which resulted in two pieces: Hafnium — study in 72-tone equal temperament (1999) — and Argon — study in 18-tone equal temperament (2000). The period following, Arabic microtonal and contemporary classical music inspired him to focus primarily on fretless bass. In 2005 he recorded with the studio group Ensemble Salazhar. Despite their highly acclaimed demo Colors the group never officially released recordings. Between 2007-2011, he collaborated with Obscura and recorded with them Cosmogenesis (2009) and Omnivium (2011). During the period 2009-2012 he rejoined Pestilence after a 15-year break and recorded their sixth studio album Doctrine (2011). Since 2011 he plays fretless 7-string basses built by German bass luthier Warwick, which are strung with a subcontra F#-tuning. Late 2014 he founded the jazz-fusion group Salazh Trio with Dutch former Ensemble Salazhar pianist Hans Grotenbreg - and later on completed with legendary Cuban drummer/ percussionist Horacio Hernández. Their debut work Circulations was released in December 2017. In October 2019 he founded the fusion-world-metal group Quadvium with fellow fretless bass player Steve Di Giorgio. In April 2020 it was revealed that Jeroen rejoined the German progressive death metallers Obscura as a permanent bass player after a nine-year break.

Jeroen Paul Thesseling (born 13 April 1971) is a Dutch fretless bass player, most famous for his work in the German band Obscura, Dutch band Pestilence and Dutch-Cuban group Salazh Trio.