Quartet No. 7 was written in 2000 and first performed within weeks after the World Trade Center attacks. It is subtitled Angels, and includes the organ along with the quartet, the only work I know of for that combination. The Quartet No. 2 (1972), the briefest, least ambitious work here, opens as a canon, each instrument eventually entering with the same material. The theme, though, is so remarkably heterogeneous in it's glissandi, trills, tonal and atonal phrases that the canonic effect is not immediately apparent. The Quartet No. 8 (2001-2002) was written as a memorial to the victims of 11th September, and moves through three movements from complete instability to a kind of hypnotic serenity. The opening movement, On wings of sound, is entirely in glissandi, with no fixed reference point anywhere; it is a palindrome canon, a fact that can hardly influence one's perception of it's eerie writhing. A field of uninterrupted glissandos also marks the opening of the Quartet No.4, from 1976-77. Here, though, an accelerative process is in motion, the lines moving faster and faster up to an unexpectedly serene close. The Quartet No.3 from 1975 is similar to the Fourth in it's use of ostinato, but comes closer than any of Coates' other quartets to the idea of theatrically contrasting the personalities of the different instruments, as in Charles Ives's Second Quartet or those of Elliott Carter. The final movement is a Prayer couched in stately chords of parallel fifths - you might notice it's repeated eight-note tune coming back in retrograde. The entire quartet takes a sense of unease from the viola and cello being tuned a quarter-tone off from the violins.