WHEN YOU THINK about the great pop culture duos, who comes to mind? In the movies, Laurel & Hardy, of course. And Rogers & Astaire. (DeVito & Schwarzenegger? Too early to tell.) On TV, it's Lucy & Desi, for sure. And Wayne & Garth (Sam & Diane . . . not!). And there are plenty in pop music: Sonny & Cher, Simon & Garfunkel . . . and Hall & Oates.

But wait -- they want us all to call them Daryl Hall and John Oates now. It's that "individual identities" thing.

And after a decade as our most reliable hit-producing, technotronic R&B dance duo, they've dumped dance music in favor of a slight return to their six-string roots -- they'll be appearing in their new acoustic incarnation at DAR Constitution Hall on Tuesday.

Their new album, "Change of Season," is a multi-crossover thing of beauty, an ideal meeting ground for the acoustic folk/Philly soul/Motown R&B/rock 'n' roll they've always shifted between.

What it is: their 19th album.

What it isn't: a dance album.

In fact, it's defiantly, almost perversely un-dance, and at a time when the charts are stomped all over by the Big Beat.

"If we were making dance records right now, you'd hear us a lot more on the radio," says Oates, calling from his Connecticut home. There's a faintly detectable grudging tone in his voice. "It's pretty well dominated by rap and dance records."

Just a few moments earlier, Hall had phoned in from his farm in Pawling in upstate New York (the album was recorded at A-Pawling Sound, a barn-turned-studio on his property).

Both men get quickly to the subject of change. The word is pretty inescapable when talking to them this time around: It's in the title of the album (which is on a new label, Arista), and prominently featured in the lyrics to many of the songs -- they've even covered the Mel & Tim hit "Starting All Over Again," and it may be an improvement on the 1971 original.

"Well, change is a pretty constant thing in everybody's life," says Oates.

"I think we used the idea of change as sort of a unifying factor, no matter what the subject was that we were talking about," Hall says, "whether it's personal change, change between people, how situations change, how people react to change, changes in the world . . . it's that kind of time, I guess. It seems like it's been a very transitional stage for both John and I. A lot of people around me have had romantic changes going on, emotional things like that. So I could comment on that."

One of the first things you notice about "Change of Season" is a musical shift, maybe even a return to their more delicate, graceful circa-1973 "Abandoned Luncheonette" sound. And that means they're singing together a lot again, which is always good news.

"But I don't consider it 'retrospective' so much," Hall says. "It's a kind of tapping into that traditional way of making music that we started with. Because that's all there was when we started back in the early '70s. I think if it's 'going back' to anything, it's back to the idea of just people playing together, and trying to be a little more organic and traditional about the playing. I see this album as a descendant of the 'Abandoned Luncheonette' album, but with a completely different attitude."

The album's format seems directly related to Hall and Oates's appearance on MTV's popular "Unplugged" show, on which rock performers strip their usually electronically reliant songs down to their almost-acoustic bedrock.

"It was the first time we'd played ensemble like that in front of people, trying to do the songs in a different way," Hall says. "That's when we realized how much we liked doing it."

"We've done the techno stuff," Oates says, "and we know what we are. We're singers. And if you're a singer, you want to sing. We're not rappers. We never were and we never will be. If it's not real to you, you can't do it, so we thought, let's just play on our strengths."

"Anyway, I'm not a very technological person," says Hall. "Even though I'm involved in all this stuff, I'm not a button-pusher. I like to play. And I felt like that was being taken literally out of my hands and the machines were making the music as opposed to me, and I didn't like that."

So on this tour, they're out to play: The band features Hall and Oates on acoustic guitars and longtime bass player T-Bone Walker on guitar and mandolin; plus backup players on "regular" drums, sax, grand piano, violin and cello. Oates says they'll be digging back for some gentler old favorites like "Las Vegas Turnaround," and taking a new look at their big hits -- including the dance tunes.

"This new instrumentation allows us to really approach even things we have played over the years in a completely different way," Hall says. "We're playing 'No Can Do,' we're playing 'Adult Education,' but it sounds different. You hear them as songs now."

And the concert will have a "very theatrical" look, Oates says, "not rock 'n' roll in the traditional sense. No moving lights or anything like that. It's all scrims and theatrical production elements. We'll be sitting around playing, so we wanted the show to move."

After the tour, both Hall and Oates plan to produce other artists and devote themselves to solo albums. Hall already has two solo projects under his belt (including the can't-hear-the-songs-for-the-synths "Three Hearts in the Happy Ending Machine"), and Oates says he's finally ready to step out alone.

"I never did one because I never really had the kind of songs or the specific idea of what I wanted to do," he says. "I didn't want to do one just to keep up with the Joneses -- you know, 'Well, Daryl did one, so I have to do one, too.' "

From their separate corners, they agree their duoship, or whatever you want to call it, continues strong and valuable.

"It's actually good in a lot of ways to have a partner," Oates says. "You know, when you have your up times, you're sharing them. And when you're having your down times, you have someone to fall back on."