A one-man pop/jazz/blues band - a cappella and ad lib

WITH technical precision that would make an opera star's jaw drop, singer Bobby McFerrin can jump back and forth from bass notes to falsetto melodies in one breath. He can sing two notes at once. And he loves to see his audience having a good time.

``It's the most exhilarating experience of my life,'' says Bob Stoloff, a Berklee School of Music professor, who jumped up on stage for an impromptu ``jam session'' with Mr. McFerrin during his concert last weekend at Berklee. Funny thing was: Neither man had a trumpet or guitar or piano. They created their own ``instruments'' with their voices.

``There are a lot of singers who are real nice to listen to, but the real task of any artist is to get inside people and change them - enlarge their hearts,'' McFerrin said in an interview after the show. (He will perform at Berklee again on Monday.)

McFerrin's solo a cappella singing has taken him to Europe, where German critics labeled him ``Stimmwunder,'' or ``Wonder Voice.'' He adds improvised riffs in between lyrics that give the impression there's a backup band in the wings. He slaps his chest with one hand to keep the groove, slides his other hand down the neck of an imaginary bass, and stamps his foot to the beat. Dressed in jeans, sneakers, and a flannel shirt, McFerrin is a one-man band, comedian, and teacher - who defies the traditional image of a pop singer.

Last month, McFerrin won a Grammy Award for Best Male Jazz Vocalist for the second year in a row. And his latest album, ``Spontaneous Inventions'' (Blue Note), debuted on the pop charts in March.

At the Berklee concert, McFerrin's and Stoloff's vocalizing began as a quiet calypso rhythm with deep bass notes and rattling percussion - all made with the throat, tongue, lips, and vocal cords. The singing soon crossed over into jazz, funk, blues and eventually segued into a hilarious version of ``Dixie,'' complete with voice imitations of piccolo and snare drum. All the while, neither singer knew what was coming next, nor that they'd end up tapping and rapping on each other's bodies, as if they were instruments themselves.

Besides McFerrin's own off-the-cuff concoctions, he sings tunes from the Beatles to Bach, from Charlie Parker to Chick Corea, and even a ``Wizard of Oz'' medley.

``I don't memorize my things, and nothing is ever really the same way twice,'' McFerrin says. ``Everything is improvised, in the sense that even though things might have a structure, the structure is used only as a starting point....''

To McFerrin, musical improvisation is just an extension of a person's natural ability to be creative.

``I feel that everyone improvises in their daily life. My wife is a great improviser; she doesn't realize it, but I watch her - like in the kitchen - and if she comes across any kind of a problem, immediately the mechanism of improvisation begins to work. It's simply problem-solving.''

The ability to improvise in music, therefore, is something anyone can learn. ``Once you realize the common factor between improvisation and ordinary events in your life and what your medium of creativity is, then it's easier to click into improvisation - rather than just learn it from a technical standpoint.''

Of course, part of McFerrin's corner on this market is his wide imagination, fueled by audience participation. ``I view the audience as my helpers,'' he says. Wandering out into the aisles, he may ask a woman her name, then make up a song about it. Sometimes he has cards available in the lobby beforehand so people can write down ideas for him to improvise on during the show. He even forms a ``choir'' of audience members who learn to be his ``backup group.''

``Some [audiences] you have to work on a bit, and I think it's because we've grown up to simply sit back and not participate in the creative process of the artist on stage,'' he says. ``But in everyone of us, there's this little part of us that wants to somehow participate in a performance.''

In his gentle, humorous way, McFerrin coaxed the Berklee audience out of its passivity and urged lightheartedness - something he had to do himself early in his career. ``I used to take myself a lot more seriously, '' he says. ``I wasn't so open to having fun with the music. But that was something that just gradually came out. There was always this `fun bubble' in my throat that always wanted to come bursting out.''

Though McFerrin has had little formal voice training, his parents (his father sang baritone at the Metropolitan Opera; his mother is a college voice teacher) gave him support early on. ``I learned a lot of [technique] just being around my parents when they were giving lessons.''

In his own teaching, McFerrin sees the dangers of ``information overload.'' Some of his students ``have had too many teachers, so here I am, their 21st teacher, and when I tell them to do something, they run through all their teachers telling them to do the same things. By the time they've got the information, they don't know what to do anymore - they're stuck.''

Singers today can also be hampered by what the music world expects them to sing.

``If you're going to go for the gold in pop music, there's a formula that you pretty much abide by,'' he said.

``The record companies are saying, `This is the sound of music today, and if you want to be successful, we'll just surround you with this stuff, and you do your thing, but we're gonna put your thing in this box here, and what's gonna come out is going to be popular!''

McFerrin said he'll soon be leaving solo work to collaborate with other artists - dancer Meredith Monk, for instance - which will feed him with new ideas. ``I'm getting to a critical point in my career where it would be real easy for me to get stuck doing solo stuff. If you're doing something long enough, people begin to see you as that one thing, and they won't let you change.''

Whatever McFerrin ends up doing along his career, it's safe to say there will be a crowd close by, because close interaction with people is very important to him.

``There's only one thing that I do consistently [before going on stage], and that is to stop and reflect on why I do what I do. [It's] simply to make people happy.... Not to dazzle with technique and fireworks, but simply to make people feel joy. That's my job.''