The works from 1992 and beyond that Philip Glass has designated as his "symphonies" are a real mixed bag: There are the quite effective "Glass meets Bowie and Eno" first (Low) and fourth (Heroes), the rather dull second, the fantastic third (for strings only), and the sprawling pseudo-spiritual mess of the fifth (Choral). [A seventh (Toltec) and eighth have also been composed but not yet recorded.]
Though it may sound like the name of a Star Trek episode, Plutonian Ode is actually the title of the 1978 Allen Ginsberg poem that inspired Philip Glass's sixth symphony. This isn't the first time Glass has worked with the late "poet laureate of the Beat generation" and his texts: there was also the disastrous Hydrogen Jukebox, and the rather nice (and short) Echorus.
It is a curious and undeniable phenomenon that the more "interesting" Glass' music gets, the less interesting it actually is. There is probably more harmonic and melodic content in the first 10 minutes of his Symphony No. 6 than in the entire five-hour duration of Einstein on the Beach, but it ends up sounding like second-rate Zemlinsky, third-rate Berg or fourth-rate Philip Glass. Repetition, gradual process, static harmonies, churning rhythms — these are the hallmark "minimalist" ingredients that make this music tick. The more Glass tinkers with this formula, the less effective the result. I suppose you could say the same thing about his fellow "former minimalists" Steve Reich and John Adams, but Glass's music seems to be most affected by the "more is less" paradox. (Actually, of the "big four" founding fathers of minimalism, only Terry Riley has really managed to develop an effective and compelling new compositional style, in my opinion. He desperately needs a new website, however...)
Symphony No. 6 is written for full orchestra and soprano (the Bruckner Orchester Linz and Lauren Flanigan in this recording), and that's the other problem — the soprano is almost always present, warbling near the top of her range throughout most of Plutonian Ode's 50-minute duration. This kind of singing is frankly just not something anyone should have to listen to (or perform) for this long, and now I know why there aren't many other symphonies for soprano and orchestra out there.