A cappella singing that goes beyond the barbershop. The Bobs master any style - jazz, funk, high-brow, or punk

They call it ``Bob music,'' for lack of a better description. No one's come up with anything better. All that anyone can agree on is that the Bobs, a four-member group from San Francisco, sing a cappella. They spend a lot of time telling people what they're not: doo-wop, jazz, or barbershop. Critics, scratching their heads in puzzlement, have compared their supple voices and stunning harmonies to the Hi-Los, Lambert Hendricks & Ross, the Beach Boys, and Manhattan Transfer.

And Devo. With perhaps a little Robert Wilson or Philip Glass thrown in. Keeping the artful arrangements from getting too artful, the Bobs punk it up with new-wave dissonance, minimalist monotone repetitiveness, and the macho explosiveness of rap. With hand slaps and strange mouth noises, they provide their own percussion: air guitar, air drums, air accordion, air bass, and ``Jane Eyre,'' says Gunner (Bob) Madsen.

They also write 85 percent of their own material -funny, off-the-wall, sometimes earthy stuff about, say, the feeling of being very large right before you fall asleep. Or of having to mop. Or wanting to be somebody's third-world country (``I'll build a wheel-chair ramp to your heart.'') They got their name from the dog show term ``Best of Breed.''

While no one can focus on a genre for the five-year-old group, most agree that the Bobs are pretty sharp. They have two records out and were nominated for a Grammy in 1985 for best vocal arrangement. This year they started writing and performing topical songs for National Public Radio's ``Morning Edition.''

They're considered folk enough to get invited to major folk festivals, jazz enough to open for Sarah Vaughan, weird enough to share the stage with Robin Williams, and high-brow enough to go to Spoleto and Wolf Trap. Not to mention festivals and clubs in Europe.

At the Newport Folk Festival in August, they were perhaps the most unfolky group there, but no matter. From the tight harmonies of the Beatles ``You Really Got a Hold on Me,'' to the jungle screeches of an original tune, ``Banana Love,'' their high energy and excellent musicianship made the sun-drenched audience perk up.

Three of the Bobs were in Boston for an interview just before flying off to the Chautauqua Festival in Boulder, Colo.

``Nowadays, I find rock-and-roll music the same,'' says Matthew (Bob) Stull. ``There's hardly any difference between groups. When I was younger, there were words that you listened to in a song. You don't hear that on the radio anymore. It's all poison and mega-death.''

The group likes the fact that because they don't fall into a particular category, their audiences are diverse. They've collaborated with dance groups at New York's Lincoln Center and in San Francisco. ``That brings the dance crowd to hear us and it brings our crowd to see the dance,'' says Jamie Scott, the lone woman. ``Another thing I like is when people either bring their children - we've had four- and five-year-olds that really like it - or people will bring their grandparents.''

``Yeah,'' butts in Gunner. ``The first record became a children's record for a lot of people. People would buy it at concerts and say that their 3-year-old would play it over and over again. And they'd say `I wish you come out with another record because the kids are driving me crazy.' That surprised me a lot. I thought of us as on the intellectual side.''