Mutable Music's Spectrum is a short, LP-length disc featuring two masters of the middle ground between classical composition and jazz improvisation -- Muhal Richard Abrams and Roscoe Mitchell -- in a combined effort as improvisers, Romu, followed by two composed orchestral works performed by the Janácek Philharmonic under Petr Kotik; Non-Cognitive Aspects of the City -- by Mitchell, with a text of Joseph Jarman delivered by baritone Thomas Buckner -- and Mergertone by Abrams. Romu is a soulful duet between Abrams' piano and Mitchell's alto saxophone that represents both individual streams of searching and a spontaneous confluence of ideas; figures are effortlessly cast back and forth between the two players, are modified, these gestures lead to other things along the way and the whole journey ends very calmly and naturally at 12 minutes. Mitchell's Non-Cognitive Aspects of the City is both a narrated orchestral work (like Copland's Lincoln Portrait) and an orchestral lied, as vocalist Buckner is required both to speak and sing. The piece has a beautiful, Ivesian orchestration and Buckner does seem to be performing from the perspective of the "vox populi" similar to Ives' application of unison choral lines in works like Lincoln, the Great Commoner. Abrams' Mergertone, which also uses electronic keyboards at least at its start and later, a concertante solo piano part, is more impressionistic, declamatory, and spectral than the Mitchell, which has its text to provide continuity and direction. However, it could hold its own at a Darmstadt Festival without much trouble, but is not overtly Western stylistically or particularly "third stream," either.
Included in the book is a fine essay by George E. Lewis that reviews Mitchell and Abrams in the context of various pros and cons regarding improvisation and fixed music. It's a shame that the text of Jarman's poem isn't also included, but it is not as though one cannot divine the words from Buckner's delivery of them on the recording. Mutable Music's Spectrum demonstrates how Abrams and Mitchell can both be well inside the established norms of composition and improvisation and still tread somewhere off the path; it likewise demonstrates the vital contributions these masters continue to make in the realm of American music.