In next week’s paper I’ll be recommending a free concert in Millennium Park on Mon 8/22 that celebrates the upcoming 75th birthday of composer Steve Reich. One of the pieces on the excellent program is Mallet Quartet (2009), a mesmerizing, almost jazzy composition for two vibraphones and two marimbas. The first recording of the piece, performed by New York’s terrific So Percussion, is included on Reich’s next album, WTC 9/11 (Nonesuch), which was originally scheduled to be released on September 6. Today comes news that the release has been postponed for two weeks, until September 20, so new album art can be created.