Jeroen Paul Thesseling (1971) followed his first classical violin lessons at the age of 7 and started his study bass guitar in 1988 at the ArtEZ School of Music in Enschede, the Netherlands. After playing metal and jazz in his late teenage years he collaborated with the Dutch group PESTILENCE from 1992 till 1994, recording their jazz- fusion influenced album 'SPHERES' (1993). From 1995 he experimented with different octave divisions. In 2005 he recorded his first fretless work with the studio quartet ENSEMBLE SALAZHAR. From 2007 till 2011 he collaborated with the German group OBSCURA with whom he recorded the albums 'COSMOGENESIS' (2009) and 'OMNIVIUM' (2011). During the period 2009-2012 he rejoined PESTILENCE after a 15-year break, recording the album 'DOCTRINE' (2011). Since 2011 German bass luthier WARWICK built fretless 7-string instruments for Jeroen which are strung with a sub-contra F#-tuning. In 2014 he founded the jazz-fusion group SALAZH TRIO with Hans Grotenbreg - piano, electric piano, synth - and later on completed with Horacio 'El Negro' Hernández - drums, percussion. Their debut work 'CIRCULATIONS' (2017) is available in digital download format on iTunes, Spotify, Deezer, Amazon and other digital music platforms. Currently, the group is working on a second studio album.