The percussionists play (at various times) three marimbas, two vibraphones, two bass drums, crotales, sticks, and tam-tam.
The piece is broken into five movements and, like many other Reich compositions, Sextet has an arch form: A-B-C-B-A.
These cycles use dominant chords with added tones to give it a darker, more chromatic sound, much like Reich's previous piece, The Desert Music.
Vibraphones are normally incapable of sustaining pitches at the same volume like wind or string instruments; they act much like a piano, where notes are struck and then allowed to ring, eventually decaying.
To give the work more depth in the lower pitch ranges, the bass drum is employed with doubling from the pianos or synthesizers.