ERIC HILTON and Rob Garza, collectively known as Thievery Corporation, are princes of local nightlife. So it's not surprising to glimpse them moving through the crowd upstairs at U Street's Local 16, one of several local clubs and restaurants that Hilton co-owns. Or at Georgetown's Govinda Gallery, wearing their trademark pinstripes, as they host the opening for an exhibition of photographers whose work is also featured on the Corporation's new album, "The Richest Man in Babylon."

Except that the Local 16 event was a fundraiser for the D.C. Statehood/Green Party, complete with blistering comments from Ralph Nader. And that the photos were stark black-and-white images from such war and famine zones as Ethiopia, Kosovo, Colombia and Belarus. And that the new album's title song features guest vocalist Notch decrying the "wicked stench of exploitation." Could D.C.'s masters of chill-out be feeling the heat?

"We have political ideas, like anybody. But I think it's more social than political, just more a general kind of empathy," says Hilton, sitting with Garza in the group's small recording studio at the back of 18th Street Lounge, another of the clubs owned by Hilton and his partners. "I like the Statehood/Green Party very much and feel an affinity with them. But that's personal."

"I think we just wanted to get away from the whole lounge, chill-out culture of, 'Let's make an instrumental track that repeats for four minutes,' " says Garza of the new album, which combines elements of samba, reggae, trip-hop and Indo-Persian music, among other styles. "We wanted to really develop our songs, to get more into songwriting."

The 18th Street Lounge is arguably the epicenter of the local "downtempo" scene, yet Hilton is skeptical of what such terms represent. "I can't think of a more vapid genre to create and market," he says. "It reminds me of easy listening back in the mid- to late-'60s. It's funny, because Rob and I collect a lot of those easy listening records, and we find these incredible gems within that genre. But most of it is just schlock.

"We're not into the idea of, 'Let's just kick back, have a drink and watch the world go by.' I don't think that's something that either of us believes in too much. I'm still trying to figure out what 'lounge culture' means. I DJ'ed here last Saturday night, and I was playing everything from heavy dancehall music to this Afrobeat stuff, yet we were in 18th Street Lounge. To me, that was appropriate music for this place."

"That's one of the things with labels," Garza says. "If you look at a term like easy listening, Antonio Carlos Jobim could be considered easy listening, even though he's one of the greatest composers of the last century. Or somebody like Henry Mancini or Burt Bacharach -- people will say that's soft, so it's easy listening, but they don't hear the subtleties."

"We've obviously been put in the lounge camp," Hilton concedes, "and perhaps musically we always will be. But I don't see why if you do soft music that involves subtlety, why it can't have some substance to it also. I don't think Rob and I are interested in making music without substance."

The change, he says, is not that the latest album has a new outlook, but that it has an outlook at all. "The previous records had a vibe, but maybe not an outlook."

"I think the difference in this record is all the events of the last two years," Garza says. "September 11, the war on terror -- it's hard to want to make just a lounge record."

Besides an outlook, "The Richest Man in Babylon" has a richer, more organic sound, resulting both from more versatile multitracking technology and the presence of many guest musicians. "Actual instruments bring a lot more color to the music," Garza says.

The duo used samples, loops and sequences, the basis of their earlier work, but also played such instruments as keyboards and bass. "After doing a lot of music on our gear here, we got a little bit bored," Hilton says. "We have a deep appreciation for live music, and I think a lot of the ideas that we wanted to explore this time required some live playing."

Session players contributed percussion, guitar, horns, sitar and other instruments. Sometimes the two musicians enlisted others to replace parts they'd already recorded. "We would play a keyboard line in a groove in a song," explains Hilton, "but instead of leaving it at that, we would bring in someone like Wayne Wilentz, who's a jazz keyboard player, to play the riffs a little bit better, with more flourishes."

The album includes such out-of-towners as British singer Emiliana Torrini and reggae vocalists Notch, Shinehead and Sleepywonder. But musicians like percussionists Robert Berimbao, Javier Miranda and Sonny Caberwal and guitarist Chris Vrenios are local, discovered at places like Rhumba Cafe, a Garza hangout, or 18th Street Lounge itself. "If I'm anyplace where I hear somebody who's good, I take note," Hilton says.

The expanded use of accompanists also reflects the changes in Thievery Corporation's live show, which has evolved from simple DJ sets to an ensemble band that includes five singers, two percussionists and a guitarist as well as the two masterminds. "We're doing beats and effects, samples, keyboard lines, and tape delays," Hilton says. "Obviously the music we make can't just be redone right on stage. We play the same list night after night, but we play around with individual songs."

The group is more successful in Europe than in the United States, drawing enthusiastic crowds from Portugal to Turkey. To handle the logistics of such distant treks, the largely self-sufficient duo -- which runs its own label, ESL Music -- has hired a live-appearance manager. The band's tours are now overseen by Seth Hurwitz, co-owner of the 9:30 club, where the Corporation performs Saturday night.

"People are more open to electronic music over there," says Garza of countries like Italy, where the new album moved 15,000 copies the first week, outpacing its U.S. sales.

"I think they're more open to eclecticism too," Hilton adds. "It seems like every negative review in the U.S. was making fun of the record's perceived multiculturalism, which I thought was really strange. But over there, they embrace it."

If Hilton and Garza aren't excommunicated from the lounge-revival movement for criticizing its banality and kitsch, the Corporation's live show might be the final offense. "People are surprised, but I think pleasantly so," Hilton says. "About two-thirds of the way through the show, they get the idea that this is going to get more and more up-tempo. By the end, it's very intense."

"It starts off very mellow," agrees Garza, "and then toward the end it's just almost . . ."

"Heavy metal," Hilton proudly interjects. "There's even crowd surfing!"

THIEVERY CORPORATION -- Appearing Saturday at the 9:30 club. * To hear a free Sound Bite from Thievery Corporation, call Post-Haste at 202-334-9000 and press 8121. (Prince William residents, call 703-690-4110.)

Not-so-easy listening: Rob Garza, left, and Eric Hilton.