PSR is an experimental ambient improv duo that began in late 2003 as a side project of At Knifepoint (now Pulsar47), a post-rock band hailing from Champaign/Urbana, IL. It all started when Dave and Aaron began getting together for frequent jam sessions, often times during post-show At Knifepoint parties. They began to develop their unique sound, built on a completely improvisational foundation. Field testing of the early PSR recordings was done by playing them in public at subliminal levels on Dave's cassette player.