Jeroen Paul Thesseling

Thesseling began studying bass in 1988 at the ArtEZ School of Music in Enschede, Netherlands. Between 1992 and 1994, he was a member of Pestilence, with whom he recorded the jazz fusion-influenced album Spheres.[3] 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.[4] In 2005 he recorded with the studio group Ensemble Salazhar.[5] Despite their highly acclaimed demo Colors the group never officially released recordings.[6] Between 2007 and 2011, he collaborated with Obscura and recorded with them Cosmogenesis (2009)[7] and Omnivium (2011).[8] Between 2009 and 2012, he rejoined Pestilence after a 15-year break[9][10] and recorded their sixth studio album Doctrine (2011). Since 2011, he has played fretless 7-string basses built by German bass luthier Warwick; they are strung with a subcontra F#-tuning (F#₀–B₀–E₁–A₁–D₂–G₂–C₃).[11][12][13] In late 2014, he founded the jazz fusion group Salazh Trio[14][15] featuring legendary Cuban drummer/percussionist Horacio Hernández. Their debut work Circulations was released in December 2017.[16][17][18] In October 2019, he founded the fusion-world-metal group Quadvium with fellow fretless bass player Steve Di Giorgio.[19][20][21] In April 2020, it was revealed that he rejoined the German progressive death metal band Obscura as a permanent bass player after a nine-year break.[22][23][24] Jeroen endorses Warwick basses and plays Warwick Thumb NT series exclusively since 1993.

Warwick 7-string basses (customshop)

• Warwick Thumb NT7 fretless Ebony fingerboard (2017)
• Warwick Thumb NT7 fretless Snakewood fingerboard (2013)
• Warwick Thumb NT7 fretless Ebony fingerboard (2011)

Warwick 6-string basses

• Warwick Thumb NT6 fretless Macassar Ebony fingerboard (1993)
• Warwick Thumb NT6 fretless Ebony fingerboard (1991)
• Warwick Thumb NT6 Wenge fretboard (1991)
• Warwick Thumb NT6 fretless Asian Ebony fingerboard (1989)
• Warwick Thumb NT6 Wenge fretboard (1989)

Live amplification

• Warwick LWA1000, WCA 115 CE LW cab, WCA 115 CE LW cab (left)
• Warwick LWA1000, WCA 115 CE LW cab, WCA 115 CE LW cab (right)

Recording gear

• Warwick WNJHPR40 preamps (stereo pair)
• DBX 160A compressors (stereo pair)
• Aurora Audio GTQ2 stereo preamp
• Heritage Audio HA73X2 stereo preamp
• Kush Audio Electra stereo parametric equalizer
• Palmer PAN03 four-channel active DI

Studio

• Sadist – Firescorched (tba 2021)
• Salazh Trio – Circulations (2017, Salazh Trio)
• Obscura – Omnivium (2011, Relapse Records)
• Pestilence – Doctrine (2011, Mascot Records)
• MaYaN – Quarterpast (2011, Nuclear Blast)
• Obscura – Cosmogenesis (2009, Relapse Records)
• Pestilence – Spheres (1993, Roadrunner Records)

Live

• Pestilence – Presence of the Past (2015, Marquee Records)

Compilations

• Pestilence – Twisted Truth (2020, Warner Music Group)
• Pestilence – Prophetic Revelations (2018, Hammerheart Records)
• Pestilence – Reflections of the Mind (2016, Vic Records)
• Lange Frans – Levenslied (2012, TopNotch)
• Pestilence – Mind Reflections (1994, Roadrunner Records)

Music videos

• Obscura – Anticosmic Overload (2009)
• Pestilence – Mind Reflections (1993)

• Official website