It took a pair of self-proclaimed “space-age pimps” to do it, but OutKast brought together all sides of the hip-hop nation last Sunday night at the Orpheum Theatre. From white dudes in hoodies to black girls in leopard-print micro-skirts, it was a youthful, multi-culti crowd that proved OutKast’s popularity to almost anyone under 30. Actually, most of the crowd seemed to be well under 20 — not including the various moms/dads/chaperones in tow. Despite their broad-based national appeal, the Atlanta-based duo favor a decidedly regional style of hip-hop. This is some “Dirty South shit,” they reminded us — which means brain-tickling bass, quick-tongued double-time flow, and a mess of moral and ethical contradictions that would take Tipper Gore years to figure out.

At the heart of OutKast’s appeal is the yin-yang dichotomy between Andre 3000 and Big Boi — the poet and the playa. On Sunday, Andre played the Funkadelic freak to the fullest. Sporting a glittering turquoise jump suit (completed by codpiece and gray wig), he came off like a mix of Sgt. Pepper and Liberace and Star Trek — on acid. Big Boi dressed with down-home street style, fresh-dipped in fuzzy white Kangol, fat gold chain, and shiny denim. Flip-flopping from anti-materialist stage patter to cheddar-loving bounce (“Get Rich to This”), fiery political rhetoric (“Gasoline Dreams”), and thugged-out posse cuts (“Gangsta Shit”), the pair highlighted their odd-couple incongruity while proving to be a potent and telepathic hip-hop tag team.

Performing from a set that resembled the inside of a musty cave, OutKast played cuts from deep inside all four of their albums, including a large chunk of their recent hit, Stankonia (LaFace). Accompanied by a DJ, two guitarists, three back-up singers, and on occasion a quartet of male dancers, they had no problem re-creating the soulful mix of gospel voices, psychedelic guitars, and skittering beats that form the core of their sound. And being Southern, these guys cranked the bass way up (at one point I swear my molars shifted), which didn’t work so well in the dome-ceilinged Orpheum.

Besides the acoustical troubles, there were some pacing problems. An early introduce-the-band segment derailed the ferocious energy of the opener (“Gasoline Dreams”), and a slew of second-string MCs (Big Gipp, BackBone, Slim Calhoun) put a damper on the show’s middle section. But when OutKast finished the two-hour show with the incredible triple punch of “Rosa Parks,” “Ms. Jackson,” and “B.O.B.” (the best junglized-Afro-metal-crunktastic cut ever), all sins were forgiven.