Few bands could have conceived of, let alone pulled off, the exercise in excess that Dream Theater have with The Astonishing.

In a vast catalog that includes several album-length conceptual statements -- Metropolis, Pt.

2: Scenes from a Memory, Six Degrees of Inner Turbulence -- this is so extreme that it pushes at what their fans (a fanatical lot) may accept.

Guitarist John Petrucci has written a double-disc sci-fi rock opera, set in a dystopian future in an invented country (the package contains maps).

In it, music created and/or performed by humans has been outlawed by the state.

Only government-sanctioned and programmed machines are entrusted with those functions.

A small band of rebels cling to and fight for the vision (and redemption) of human music.

Petrucci consciously sought to create as grand a statement as Tommy, The Wall, and Operation: Mindcrime.

Whether or not he and the band have succeeded will likely be debated for some time.

Well over two hours long, The Astonishing contains 34 tracks.

Dream Theater are accompanied by the Prague Symphony Orchestra and three choirs, all conducted by maestro David Campbell (Beck's dad).

Petrucci entrusted the character voices to vocalist James LaBrie, who executes them authoritatively with his vast range and remarkable control.

Keyboardist Jordan Rudess is the wheel all this music turns upon.

In addition to his grand pianos, organs, and beautifully wrought synth sounds setting up melodies and harmonies, he handled the choral arrangements, and provided orchestral direction for Campbell.

Petrucci's guitar playing is, as usual, breathtaking (check "A Better Life"), though he doesn't solo as much.

Bassist John Myung and drummer Mike Mangini aren't used as prominently as they usually are, but a musical narrative of this scope demands rhythmic flow and consistency.

There are a couple attempts at singles -- the excellent melodic prog rock of "The Spirit of Music" and the more metallic "Moment of Betrayal" -- but singles aren't the point.

Several other individual selections do stand out: "Dystopian Overture" (which deliberately pays momentary homage to the "Overture" from Tommy); "A Life Left Behind" (whose intro reflects Yes' influence); "Three Days" (Mangini's shining moment, which commences as a ballad but transforms into a prog metal anthem); "Chosen" (a power ballad sure to become a concert fave); and "The Path That Divides" (an angular metal powerhouse overdriven by Rudess' manic organ).

But these tracks serve almost as "arias" in classical opera; they are connected by much more "recitative" (a narrative device to move the plot along).

Though it may be grandiose to say, like opera, The Astonishing shouldn't be disassembled, but judged holistically.

It was planned as an immersive, one-sitting listening experience.

As demanding as it is, the story and music are worth the effort.

Dream Theater have invested in the "album" concept (and in listeners' attention spans) even as the music biz doubles down on the notion that long-players are merely envelopes to hold singles.