At 37 minutes, Mezmerize, the first half of the forthcoming double album from heavy mental quartet System of a Down, is the band's most punctual outing. But somehow, the group manages to cram in what feels like three albums' worth of chaotic riffing, thunderous double-bass-drum blasts, operatic crooning, growling death roars and blazing accordion — yes, accordion — into the LP's 11 songs.

Perhaps System's tightest and most intense material to date, Mezmerize — which comes out on May 17 — is loaded with breakneck, Slayeresque riffs and a complex sense of melody that's reminiscent of Faith No More. Fans will probably be jazzed to hear that the album recalls the band's 1998 self-titled debut more often than the less frenzied Toxicity — anyone concerned that songs like the lighter "Aerials" and Toxicity's title track signaled a weakening of the group's sound, fear not.

Mezmerize starts deceptively with an acoustic intro, but then lunges forward at bullet-train speed with the furiously paced first single, "B.Y.O.B." Perhaps the most political song on the album, its lyrics pose the question, "Why don't presidents fight the war?/ Why do they always send the poor?" (see "System Of A Down Shoot Fiery 'B.Y.O.B.' Clip, Find Inspiration In Fistfights").

The band keeps the intensity on full through the following seven songs.

"Revenga" features guitarist Daron Malakian's intricate instrumental work and a deft balance between frontman Serj Tankian's more soothing vocal persona and his trademark rapid-fire rantings. Malakian's piercingly high vocals are actually featured more prominently throughout Mezmerize than any of the band's previous efforts: The guitarist and Tankian trade off lead vocal duties at various points in almost every track, and practically every chorus is dual-harmonized.

"It's the first time that [Malakian] is actually singing lead as well as harmony in most cases," Tankian said. "I love those harmonies; I love those pushing vocals going against each other. Our tonality is just so different that when you put them together, it's like one. If you balance it right, it's like one voice."

Then comes the spastic aural assault of "Cigaro," followed by "Radio/ Video," which boasts a playful, almost circuslike tempo early, and then kicks into high gear with bombastic bass licks and abrasive guitar work. Tankian spouts seemingly free-associated lyrics ("Gonorrhea, gorgonzola") on the hyper "This Cocaine Makes Me Feel Like I'm on This Song," and it burns rubber with complex riffage and bass lines before stopping on a dime.

The disc finally eases down for its two closers, the digitally manipulated, synth-heavy "Old School Hollywood," and the anthemic "Lost in Hollywood." According to Malakian, the lyrics to the former were inspired by an uncomfortable experience he had playing in a celebrity baseball game.

"I went there just being a guy, not taking it so seriously," he said. "I just wanted to get a shot at hitting the ball in Dodger Stadium, because I am a sports fan. But everyone else there was wearing [serious sports equipment] and they were all in uniform and there was a coach on the team. And I was really uncomfortable that day, to be honest: It was just a strange vibe to be on the same team with people that you grew up watching on television. like Tony Danza. So I just went home and wrote a song — that's just what happens to me when I go through some kind of traumatic experience."

So far, details have yet to surface regarding Hypnotize, which is expected to come out in the fall, although it was revealed that the albums will be interactive — but not in a way you might expect. Bassist Shavo Odadjian described the halves of the double LP's packaging as one part "male," one part "female," and fans will be able to connect the cardboard packaging of both discs with an extra panel flap. With this extra bit of cardboard, which will be part of Hypnotize's packaging, you'll be able to slide the two together, interlocking them (see "Details On System Of A Down Album, Tour Emerging").

"It's supposed to be one CD at the end," Odadjian said. "It's kind of cool the way it links and it becomes one."

For a full-length feature on System of a Down, check out "System of a Down: Doubleheader"