Pat Metheny loves to confound people's expectations.

As one of the most distinctive, original guitarists of the past decade, and as one of its most successful jazz musicians, Metheny could be excused for milking the pastoral, neo-fusion sound that has made the Pat Metheny Group's albums best sellers and led to constant global tours. After all, such success is a rarity among groups that improvise heavily -- as is the makeup of his audience, which includes both jazz and rock fans, young and old.

Yet Metheny has also involved himself with artists as disparate as Joni Mitchell, Sonny Rollins and David Bowie. He's embraced and affected the rapidly evolving guitar synthesizer technology, using it to reshape sound and musical structure. He's written and performed a number of sound tracks, most recently "The Falcon and the Snowman" and "Twice in a Lifetime." He was the only jazz player at last year's Live Aid concert. Just 31, he's been a major influence on a new generation of guitarists and composers.

And now he has recorded a provocative new album and is touring with legendary avant-garde saxophonist Ornette Coleman. They'll perform at the Warner tomorrow night.

"I'm intrigued with the idea of trying to play all the music that I like and trying to deal with why I like it," Metheny explains, "as opposed to saying, 'Okay, I have a style now and that's what I do . . . I like all this other stuff but it's out of my realm.' "

He shrugs.

"Style is something that people worry too much about."

Unlike so many guitarists of his generation, Pat Metheny has never been into the speed/thrills bag. His early influences were melodic players like Wes Montgomery, Jim Hall and Chet Atkins; even then Metheny didn't buy the notion that technical bravura was a substitute for taste, imagination and the willingness to take risks.

"It's always been difficult for me to quantify what I like and what appeals to me about music," Metheny says, "but there's something I hear when a player -- and it doesn't matter what style -- is meeting the music that means the most to him and it's just a little bit out of his range. When he goes beyond what he can play . . . that effect is what has always drawn me to a particular music."

Under an unruly shock of hair that would not have been out of place in '60s San Francisco, Metheny is fresh-faced, surprisingly earnest and unaffected. He speaks in a flat midwestern accent, sounding a tad like the young Jack Nicholson, but without any sense of menace.

Growing up in Lee's Summit, Mo., Metheny found himself in a musical vacuum. "There just wasn't anybody teaching," he says. "Had there been, I probably wouldn't have gotten the playing experience, because that would have meant there was somebody in town better than me and all the people that hired me would have gladly hired some experienced guy. But the best possible teacher, as we all know, is experience, and I played four to six nights a week from the time I was 15 until I got out of high school with players who were substantially better than I was."

Which may explain the gray hairs streaking through his mop. "But I haven't had a difficult time," he insists. "I've been working nonstop since I was 15, and I've always had a gig or the possibility of getting gigs and have had lots of musicians around who were encouraging. There were times when I didn't have any money, but I never was discouraged about the music because I felt I could play better each year than I could the year before."

At 16 he was fronting a band (one saxophonist, four drummers) that played the music of Coleman and Albert Ayler, hardly the conventional vocabulary for a teen-age musician. But early on, Metheny separated himself from the masses who have an instrument and started working at becoming one of the few who had a music and a point of view.

A further sign of his precociousness: Though he never graduated from college, he taught for two years at Boston's famous Berklee College of Music. He was 19 at the time, the youngest teacher ever on staff, younger than most of his students.

"I was around musicians who discouraged me from being the next Wes Montgomery," says Metheny, explaining the development of his idiosyncratic style. "I got to play with some great Kansas City players when I was very young. I was a real eager kid, I'd get the newest Pat Martino and John McLaughlin records and would transcribe tunes and bring them into the gig. But when I was trying to sound like somebody else, these guys would put me down for it, blatantly. I think they genuinely preferred what I was playing when I played my own way as opposed to trying to sound like someone else. And I always ended up sounding like what I sound like anyway.

"Playing fast on guitar, playing hip lines fast, is extremely difficult," he adds, "and very few people have done it well. Anyway, I couldn't think fast enough to play hip lines fast so I would just play slow . . . or fast enough to make it seem like I could play fast if I wanted to," he says, laughing.

"Now I can play fast and play pretty hip, but it's only been in the past three or four years that I could do that. It's still not anywhere near the level that I want, but it's starting to come."

Metheny's first major national exposure came during his three years in vibraphonist Gary Burton's band. It was here that the Metheny sound -- characterized by clean, uncluttered playing, melodious tunes couched in conventional song structures, persuasive rock-flavored rhythms, sophisticated improvisations, imaginative use of electronic technology to create ethereal, impressionistic textures and narrative underpinning -- came into focus.

"Those Kansas City musicians would say, 'You've always got to tell a story,' " Metheny recalls. "And when people would compliment me, they'd say that was a quality they liked, that I'd have things lead from one thing to another. I wasn't trying, but I guess my instinct was to do that. All my favorite players have that quality, they keep you hanging, waiting to hear the point. It's narrative, rather than just linear, which I like. Trane managed to do both; in fact, he could do it in 3-D!"

After leaving Burton and slowly putting together his own group, Metheny embarked on the rigorous touring schedule that has made him one of the most visible figures in contemporary jazz. In 1977, its first year, the Pat Metheny Group put 150,000 miles on its bus; now the musicians fly around the country and around the world (including South America, Europe, Japan and Australia in the past year).

One other thing set Metheny apart: a willingness to incorporate elements of the music styles he'd grown up with, including rock, folk and country, into his sound without compromising its integrity.

"It's not a conscious thing, it's the natural thing, the logical thing," Metheny insists. "The thing that's amazing about the jazz form is that it's so resilient and so strong that it's capable of supporting almost anybody from almost any background. We see this all the time, musicians come to New York from all over the world with a common language and vocabulary that we all understand, tunes that we all know, records that we've all listened to, and a respect for what's gone down over the past hundred years that's common to all of us.

Bringing your own background to jazz, Metheny continues, "is not just a good idea . . . it's essential. My main responsibility is to play the music that I like, that I feel close to. I saw 'A Hard Day's Night' 15 times when I was 11 and I've always kept up with the Top Ten. I always was a pop music fan; I essentially became a musician because I was a fan of music. You can't function as a jazz musician without dealing with all of your personal quirks; you have to face them every night."

Not surprisingly, his music was accessible -- and sure enough, it was soon accessed by a sizable portion of the public. Being popular, he says, suits him just fine.

"The thing that drives me crazy," he complains, is musicians who give an audience the impression that they're performing "because that's how they make their money . . . they don't want to be there, they don't care that you're there, they're going to play what they're going to play. You're either going to like it or hate it. They don't care and then they're going to go home . . . I can't stand that, and that's always bugged me about jazz. When people who are nonmusicians and not serious listeners say 'I don't like jazz,' it doesn't surprise me . . .

"Jazz is the greatest music that America has ever produced. But the musicians who play it are a lot of times their own worst enemy, because they feel that because jazz is such a great art form, they've already gotten to the point where they deserve something just by virtue of their being a jazz musician. I can't stand that."

Despite a genuine affection for and a solid grounding in bebop, hard bop, free jazz and fusion, Metheny has managed not to sound like anyone else. He's been an innovator, not an imitator, as influential in the past decade as John McLaughlin and Larry Coryell were at the beginning of the '70s.

But while many of his contemporaries opted for either the heavy electronics of fusion or the simplicity of straight-ahead jazz, Metheny evolved a wide-open, earthy sound that used technology to enhance the "acousticity" he favors. Which is ironic, he points out, since "the first thing I did when I got a guitar was plug it in. I've been dealing with electricity from the absolute beginning. Every performance I've ever done has been electric, and the goal for me has been to try and deal with technology in a responsible way.

The past five years, however, "have been a monsoon of new possibilities," says Metheny, tempering his observation. "I feel so lucky to be the age that I am because I grew up hearing a lot of acoustic music and I have a frame of refence based on acoustic music that's real. As a result, when I deal with electric instruments, I have a sound in my mind that I can compare things to. But I worry about a young musician who's 8 years old now. What's his frame of reference going to be? If he gets a DX7 [synthesizer], he's never going to hear a real instrument."

Reservations or no, Metheny has been in the forefront of the technological revolution. For the last six years, he's been a consultant and point man for New England Digital, the Rolls-Royce of computer-based instruments; he was particularly active in designing the guitar interface for the company's Synclavier. His arsenal of guitars, many custom-designed, is backed up by a phalanx of digital delays, guitar synthesizers and other tools of computer-based technology.

"I'm one of the more experienced musician-users," Metheny points out. "I've kind of grown up with it, know it in an intimate way . . . It's mainly exciting on a compositional level. It helps me stay organized, like a word processor for musicians."

He notes that in the pre-synth era, "the touch of the player had a lot to do with what came out. Which is the big problem with today's instruments. But they'll get to it soon, probably by this afternoon because it's happening so fast. We're only this year getting a drum machine that's got dynamics. For six years, they were either on or off; you couldn't get any graduation. The Synclavier or Linn 9000, the most sophisticated sequencers available, only have eight levels of dynamics; I hear at least 50 and I expect that to come out of my instrument."

So Metheny and other musicians in the vanguard are caught in a curious dilemma, looking for a balance between the spontaneity of improvisation and the limitations of the rapidly emerging technology. What's both frightening and exhilarating, he says, is that "the technology is so far beyond where we're at as musicians." He has just picked up a new Synclavier hardware option "where you record right to disc. You don't go to tape ever and it's better quality than the best digital recording.

"It's all in memory, and anything, everything can be punched in, note by note, phrase by phrase, word by word, hit by hit, and it's going to be the easiest thing in the world to do. There will be pitch devices on every channel of every input of every console so that any instrument can be any other instrument. It's just going to be unbelievable, but it's also intimidating, like having a 90-piece orchestra sitting in the other room waiting for you to pass out the parts."

Metheny compares all this new technology to a painter discovering new colors and finding a way to make a canvas three-dimensional. "It's a quantum leap from the options any composer's had available to him before," he says.

The downside is " 'option anxiety.' On a new tune, should I play acoustic or electric, should I play nylon string or steel . . . if I use the Synclavier, I have 3,000 sounds available on disc . . . It used to be somebody handed you a piece of music and you'd pick up the guitar and play it. Now there's just so many decisions that have to be made."

Of course, all these options without a base are meaningless. Technology without imagination, says Metheny, "can definitely lead to a dead end."

The ultimate beneficiaries will not be those who are technically proficient but have little to say, but those who have little skill but great conceptions.

"We're already seeing it in producers like Trevor Horn. This guy is no virtuoso player, but he is a brilliant musical conceptual artist and it is totally intertwined with his relationship to technology, to his ability to have a sound image in his mind and render it to life so we can hear it too. And, on a certain level, that's no different from hearing Art Tatum play."