They also include choral arrangements and instruments rarely heard in rock, such as clarinet, vibraphone and even harp.
en.wikipedia.org The piece is scored for glockenspiels, marimbas, metallophone (vibraphone without resonators), women's voices, and organ, and runs about 17 minutes.
en.wikipedia.org In addition to their usual instrumentation, they incorporated acoustic instruments like piano, vibraphone and trumpet, as well as considerable computer generated/processed sound.
en.wikipedia.org The sound is similar to a glockenspiel, but with much more sustain, similar in this respect to a vibraphone but without the vibrato.
en.wikipedia.org