On the day of their last concert here, pop duo Hall and Oates sit down in a suite at the International Hotel to discuss their recent string of successes; their attitude is one of hard-won confidence.

Everything about this unlikely pair suggests "West Side Story"--Daryl Hall with his all-American, blond good looks, rangy and athletic in a brown leather jacket; John Oates in a silky red shirt setting off his well-groomed dark hair and Latin coloring. They are part tough, part smooth, articulate and savvy, and, like their music, loaded with cosmopolitan style.

It's a natural result of having at least one single in the international top 10 for almost the entire half-year since the release of their platinum album, "Private Eyes." The first single from the album, "I Can't Go for That," has hardly begun to descend on the charts, while a second release, "Did It in a Minute," is already rising quickly. The title belies the years of creative turmoil and commercial insecurity that went into making Hall and Oates an overnight success.

In the decade-plus of their partnership, Hall and Oates have learned some hard but lucrative lessons, not the least of which was to take control of their own production, which they did for the first time with 1980's "Voices." That album typified the pop/soul, highly integrated sound that had taken them through every genre from folk to hard-rock to avant-ish pop, while a modest if confused following took shape. With "Voices," the momentum grew in direct proportion to the duo's increasing control and self-confidence.

"Basically, we have an uncluttered mental direction," says singer/guitarist Oates. "We know what we want and there's no longer any outside ideas cluttering that up."

Although he describes their music as reflecting the black, white and brown roots of their native Philadelphia, singer/keyboardist Hall rejects strict categorization. "There's definitely soul and rock, and even some Puerto Rican influences," he says, sipping water and stretching one foot out to rest on a couch. "That's why we got that 'blue-eyed soul' image. But it's a bad term. It comes from an innocence and an ignorance of the life style of the northeastern United States."

"And also of the past traditions of rock," adds Oates, leaning over to stress what he calls "our ongoing crusade" against the stratification of pop music. "Radio used to be a melting pot, and it turned away from that. We keep saying that radio ought to become more of a melting pot than it is, and it seemed to fall on deaf ears for a long time, but lately it's starting to happen again, at least in New York."

"We came from a tradition of integrated music," explains Hall. "It's all about growing up in Philadelphia where you had shows with white and black acts, and the audiences were mixed, too. There wasn't that polarization that goes down in places like the Midwest where kids don't interact with each other."

In fact, it wasn't until Hall and Oates themselves melded their Philadelphia soul influences with their affinity for traditional pop that they created a definitive sound easily at home on both "black" and "white" and even foreign airwaves. "The Police are THE world band, but I'd say we're running close behind them in terms of our popularity," says Hall, without a trace of false humility. And indeed, they have songs topping the charts in Sweden, Australia, Germany, England and Spain.

"We haven't made it to Africa yet," says Hall with the clipped, charged tones of a true businessman, "but eventually we'd like to expand to those areas." It's part of a "long-range plan" which includes cutting a Spanish-language version of "I Can't Go for That" on their return to New York. "It ought to be fairly easy to do," says Oates with a chuckle, "especially the ooh-ooh parts."

Both were in bands as early as junior high school, and Hall worked for Philadelphia's pop powerhouse, Gambel and Huff, before he met Oates. Their first encounter was in an elevator where they both sought to escape a gang rumble at a dance where they were playing with separate bands. And both insist that their success comes from musical experience, not business acumen.

"There are two kinds of music going on today, and I'm not talking about style," Hall says matter-of-factly. "There's the adolescent mentality and the mature approach, and it has nothing to do with softness versus loudness or how much you jump around, but with ability. People talk about the dreaded second-album syndrome, but who the hell cares about that? We're so far past that in terms of experience that we're capable of saying that much more. It's taken us 13 albums and a lot of work, but we know how to get exactly what we want, and that adds power to our music."

Hall gets testy at the charge that the two are commercially calculating. "We're no more calculating than we ever were. We're just better at it, and that comes with maturity. We never sit around trying to think up what's the most commercial thing we can do."

"We still share a common vision," explains Oates. "And in the actual craft of it, we know what we're doing, and we're dealing with the technical discipline of making a record, so we have to be calculating to that degree. But I just call that musical maturity."

The duo will expand on that experience when they begin work on a new album this June, but they are clearly looking forward for some rest from the road before the whole writing/recording/touring cycle begins again. They'll return to New York where Hall keeps his collection of medieval armor and Oates races around in his turbo Saab, but both are already eager to spin out some more hits.

"We're workaholics," confesses Hall. "But we're highly motivated. We have a very nebulous vision, and it's striving for completion of that vision that motivates us, causes such a great amount of energy."

He pauses, for once at a loss to express himself. "It's hard to explain, but remember that guy in 'Close Encounters,' when he kept trying to envision and recreate and get to that mountain? That's kind of what it's like for us."