Indie and prog-rock have a lot more in common than most of their listeners might like to admit. Both are dominated by apostate wallflowers who act a lot cooler and more self-assured than they really are, and their artists, despite creating an aura of aloofness, are notoriously defensive. If you wanna take the psychoanalytic bent, both have masculinity issues: Prog compensates with double kick drums and the phallic gratification of rabid shrrredding, while indie prefers to spin its shortcomings into anti-heroism. This is not to detract from the legacy of either music-- both have rich and diverse histories-- but the reps of each have been tarnished by generations of feckless dudes whose spotlight-hogging has rendered the genres unusually susceptible to generalizations. In fact, the terms themselves are generalizations, almost always used negatively: These days, bands are most commonly dubbed "prog" or "indie" when their music isn't provocative enough to earn a more individually tailored description.

On De-Loused in the Comatorium, the Mars Volta weren't straddling any fencelines. Rather than carrying over characteristics from the rough-edged indie-esque stylings of their former band, At the Drive-In, or plunging headfirst into the never-ending math equations of psilocybic canterbury prog, they artfully missed both marks: too sincere for indie but not quite prolix enough for prog; too melody-driven for prog but not repetitive enough for indie. Listeners' initial bemusement enabled the band to transcend genre reducibility, which won De-Loused quick (if hesitant) points from critics and fans. But two years later, there are few other recent records for which putatively in-the-know listeners are so cautious of voicing approval. If you liked De-Loused (or thought so, at least) but often found yourself biting your tongue in the company of others, you were probably in the majority.

The Mars Volta drew attention for its technical proficiency, but behind all the meter-changes and 32nd-note polyrhythms, De-Loused featured some very strong melodies. The album's best moments registered in part because of the galling pomposity with which they were delivered, but the tripartite solos and Cedric Bixler Zavala's ornate vocal wallpaper wouldn't have held up without a backbone. The band managed to ingratiate themselves with so many who would have otherwise relegated De-Loused to the realm of ironic pleasures because they had the tact and melodic good sense to make masturbation acceptable for a deceptively Victorian set of listeners.

Of course, there was always the kid with the green Ibanez who didn't know better and staged impromptu Omar Rodriguez-Lopez deification rituals. With no apologies, Frances the Mute-- The Mars Volta's new 77-minute, five-track, gratuitously subdivided, and feebly narrated album-- is for him. Call it what you will, but be sure to have finished your homework before tackling this gnarled swamp thing.

I'm reluctant to say Bixler-Zavala and Rodriguez-Lopez have become better musicians in the two years since De-Loused was released. Any possible strides in technical proficiency are showcased in brazenly flown-from-the-rafters pandering. But the Mars Volta are also a band in the truest, bluest sense of the word, and their strong unity actually manages to temper songs that are premised on lack of temperance. Solos are kept to a minimum; the band chug full-throttle on the same set of tires. Their most sophisticated algorithms are contained within sturdy sonic superstructures. In this sense, they're more Mastodon than King Crimson-- only they kick about a third as much ass as a Dream Theater side project.

Predictably monolithic and impossibly huge, Frances never stops chugging. Its five songs are divvied up in several, nearly indistinguishable movements, but the album moves wholly, as a gross, plodding, overstuffed mass. Opener "Cygnus...Vismund Cygnus"-- which is said to tell the story of an HIV-positive male prostitute and drug addict born out of rape, but who knows?-- builds to a powerful, string-driven climax at around the eight-minute mark but never bothers to come back down, staying aloft in a spiral of guitar arpeggios and overeager drumming before eventually devolving into a chorus of synth textures. At six minutes, "Widow"-- a yowling "November Rain"-style ballad-- is half the length as the next shortest track, and still at least two minutes too long. It, too, subdues into a wash of chattering electronics, as if an envoy to the next, equally inconsequential track.

Despite its long-windedness, Frances the Mute doesn't require a long attention span: It's as mesmeric as it is mercurial. Like an effective pop novelist, the Mars Volta manage to convey vast amounts of information in easily digestible fashion without saying much at all. Zone out to the closing 30-minute "Cassandra Gemini" for proof: Even at this length, the track seems brief, sailing by in stupefyingly uneventful fashion. What may at first seem like extraordinary, ceaseless fluidity gradually sublimates into wah-wah wish-wash. Smoke a bowl first if you need to, but nothing short of opium will convince me that there aren't more productive ways to spend 30 minutes trying to fell a redwood with a plastic spoon than listening to this beast.

At least some things haven't changed. For instance, Frances largely retains the audacity of De-Loused's lyrics. "Cassandra Gemini" approaches storytelling with the same breed of macabre circumlocution that pocked the band's debut. (A grizzled, possibly vocoded voice delivers this bracing narrative: "There was a frail syrup dripping off his lap-danced lapel, punctuated by her decrepit prowl/ She washed down the hatching, gizzard soft as a mane of needles.") But no matter what your feelings for De-Loused, at least the band had a mind to curtail their most capricious jams before they lost all context. Here, they seem hellbent on making an album that's as contiguous as possible, and the result is a homogeneous shitheap of stream-of-consciousness turgidity.