Sperm was the biggest name of Helsinki underground, having in its line-up among all Mattijuhani Koponen, P.Y. Hiltunen, Antero Helander, J.O. Mallander, Markus Heikkerц and the musical primus motor Pekka Airaksinen. The group arranged happenings, performances and concerts (with appropriate psychedelic light shows); and managed to cause some debate and public outrage at the time in Finland. Sperm created their experimental compositions using only various guitar effects and tape manipulations; the results of which could these days be called "ambient noise".