A piece of unrelenting intensity, Olson III may be one of the most powerful compositions from minimalist composer Terry Riley. Based on the same phasing principals of In C, Olson III is filled with short motives that each ensemble member must play and repeat before moving onto the next. A chorus singing "To begin" joins into the droning fray of string instruments, sawing away à la In C. For 53 minutes here, Riley (on soprano saxophone) and a teenage student orchestra at the Nacka School of Music in Sweden take this concept to the limit. Riley refused to conduct the piece, insisting that the students listen to each other and find their pace without a leader. The result is a performance filled with its own ramshackle power. Olson III moves like a runaway freight train but the listener never forgets the human element. Ebbing and flowing organically as musicians tire and find their voice, the piece is accentuated by Riley's bleats occasional poking through the fold. Someone (something?) shrieks at the 45-minute mark. No matter. You're left to guess: is this audience agony or ecstasy? Never before available, it's a must-have for fans of Riley and minimalism. Though not necessarily groundbreaking, Olson III makes an awesome impact.