 He composed the score for the film "I et speil, i en gåte" featuring Liv Ullmann.Hartberg plays in the rock band «Yoga Fire» together with Jonas Forsang Moksnes, Esben Selvig, Sveinung Eide and Søren Brandt.He has also contributed to albums by Paperboys, «Apollo», «URO» and Lars Beckstrøm among others, and has written the book "Fuck you eller penga tilbake" published on «Tiden forlag» 2009.