Growl! Metal music is big in Sweden. Since my youngest son is playing in a band I could not avoid the tradition even if I wanted to. Instead I got fascinated by the vocal technique used by the so-called “screamers” or “growlers” which is a kind of natural vocal distortion that gives the impression that the singer is ripping apart his vocal cords. I suddenly had the urge to make a piece for a “growlers choir,” something I’ve never heard (and few others have). My son managed to get me four of the best growlers from my hometown to line up for a recording session. I also asked one of them to...