[6][7] Larsen started his musical career in the 1990s as a recording engineer and worked as an apprentice under renowned black metal producer Pytten at Grieghallen Studio.

[8][9][10] He joined the hard rock band Audrey Horne with members of Enslaved, Gorgoroth, Sylvia Wane and Deride as a keyboardist in 2002.

[11] Larsen was an engineer on Enslaved's studio albums Monumension and Below the Lights, released in 2001 and 2003 respectively, before joining the band as a keyboardist and clean vocalist in 2004.

[14] In 2005, Audrey Horne released their debut album, No Hay Banda, and won the Spelleman Award in the Metal category.

[15][16] Larsen left Audrey Horne in 2007 to focus on Enslaved, but have since contributed keyboard parts and production to the band's later albums and appeared as a live guest.