QUADERNS D'ÀUDIO Conversation with Joel Peterson on graphic notation

In 2009 QUADERNS D'ÀUDIO unearthed a series of previously unpublished graphic scores, which the Valencian composer Llorenç Barber had created in Yokohama (Japan) in 2005. American composer, improviser and sound artist Joel Peterson performed them live at INCA, Detroit, in January 2012. We talked to him about the challenges of graphic notation and other related issues.