Over the course of 37 years, The Necks have released 18 albums of music that defies description: not entirely avant-garde, nor minimalist, nor ambient, nor jazz, and yet all of these, and more. The band’s extended improvisations, frequently underpinned by an insistent groove, have a deceptive simplicity that masks the music’s deep layers, leading the Los Angeles Times to call the group “a magic act masquerading as a piano trio.” The Necks make their Pierre Boulez Saal debut with a career-spanning program of classics and recent pieces.