Prog rock was a dirty phrase before Steven Wilson started Porcupine Tree in 1991.

The bloated pomp and elongated soloing of ELP, Yes, and a pre-pop Genesis - wildly successful throughout the '70s and early '80s - didn't translate and couldn't carry its rotting carcass into the waning years of the 20th century.

Wilson - a moody but realistic lyrical presence and a quietly passionate, even raw, crooner - wouldn't let go of the ghosts.

To his credit, he turned Porcupine Tree into a wrenching expressionist beast with a tender heart, a daring ambient swell and a wider range of lyrical ideals and musical influences than prog's elders would allow themselves. And for that, Wilson's Porcupines got the rapt attention of a mega-sold-out crowd on Saturday at Electric Factory.

While there were rewards for longtime fans, treated as they were to the snarky romanticism of "The Start of Something Beautiful" and the throbbing "Russia on Ice," the night's grand event was its first half - the entirety of Porcupine's new 55 minute, suite-like The Incident. After a voiceover asked for patience and quiet for The Incident's more densely somnolent moments (usually provided by keyboard/programming wizard Richard Barbieri), an evocative film presentation followed Wilson & Co. through a nexis of tracks tied to the album's sweetly bombastic title track. Now that's old school prog, yo - so much so you could imagine pigs flying behind the Pink Floyd-ish tones of "Time Flies" or the tubular bell-ringing of "Drawing the Line."

Remembering, though, that Wilson has long progressed from prog's bong-and-gong past, there were odder elements found within The Incident's mood-swinging mien. While a hammering guitar's crunch could be tied to grunge and an industrial kink could be felt throughout the rhythmic proceedings, Wilson's own voice - backed often by Beatles-like harmonies - sounded vaguely like Simon LeBon. Rather than find that disquieting, it was a strange way through which to handle the ruminative yet contagiously melodic strains of atmospheric whisperers ("I Drive the Hearse") and heavy organ-filled rockers ("The Yellow Windows of the Evening Train").

A voice as charming and mellifluous as Wilson's has meant the world to the intricacies of such a complex but concise song-suite.