David Filskov with a Roland JV-1080
David Filskov is a sound designer from Denmark who was responsible for the 'bonus' theme in Billy, along with the MIDI file music.
He has frequently corresponded with Sune M. Pedersen on multiple projects and also follows the same school of thought when approaching patch programming. David had a few of Sune's JV-1080 pieces on YouTube along with a demonstration of simulating PWM on the JV-1080, but they were later taken down.