The American composer Michael Gordon, a founding member of the New York-based Bang On A Can Ensemble, has written orchestral music and contributed scores to multi-media projects. But on Timber, he strips things down to bare basics: the piece is performed by six drummers on two-by-fours that are cut to different sizes to create various pitches. The instruments are known as simantras, percussion bars modeled on instruments used in the Greek Church and utilized by the great composer Iannis Xenakis. On this 2011 release the Dutch percussion group, Slagwerk Den Haag, performs the five-movement composition. It’s interesting to listen to a piece of music with such a limited timbral palette — the wood doesn’t have a lot of sustain and two-by-fours don’t have a lot of give. This sharpens the listener’s ears: every subtle textural shift is spotlighted. It’s fascinating to hear the rhythms gradually grow in complexity — a process that is hypnotizing and draws attention to the finest detail. Gordon’s exhaustive exploration of a very limited instrument somehow sustains musical interest throughout the piece’s 54 minutes.