The next time Tim Eriksen starts humming something different while doing the dishes, he might better pay attention. "A lot of the stuff I do around the house is the stuff people are most interested in," says the punk rock singer-turned-ethnomusicologist, speaking from his home in western Massachussetts.

Stuff like harmonic singing, also known as Tuvan throat singing, with its eerie overtones wandering above a gutteral bass line. Or shape-note singing, the centuries-old notation method and musical form usually found in hymn books. Both have worked their way into Eriksen's repertoire of northern roots music, a haunting New England-born relation of southern Appalachian song. Eriksen's drawn to both.

"In our national self-image, people locate tradition in the South and innovation in the North. They look to the Northern states for John Cage and the Southern states for Ralph Stanley. I feel like I'm kind of between John Cage and Ralph Stanley in my musical and philosophical life," he says.

To say Eriksen is a versatile musician is an understatement of the first order. A player of banjo, guitar, fiddle, bajo sexto, dulcimer and flute, he's performed folk punk with Cordelia's Dad, Bosnian pop with Zabe I Babe and South Indian classical music in college, all the while nurturing an abiding interest in the mid-19th-century music of New England.

That fascination led him to shape-note singing, and shape-note led him to Sacred Harp, a rarified a cappella form named for a book of distinctive hymns most commonly practiced in the Primitive Baptist tradition. Its four-part harmonies--intense, even raucous, and usually rendered in a minor key--are showcased in the soundtrack to Cold Mountain, which did for Sacred Harp what O Brother, Where Art Thou? did for bluegrass. Eriksen was brought in by producer T-Bone Burnett to coach other singers in Sacred Harp and perform in his own compelling voice. Nasal yet full-textured, without vibrato or ornamentation of any kind, it's a voice from another century: stoic, lonesome and without ego, as if forced by hardship to accept the dominion of greater powers.

For Eriksen, the group singing of Sacred Harp has become a passion. He regularly holds workshops, or sings, which he says feed the soul. "Honestly, I think what some people are looking for in music is work. It's that old adage that people get more out of helping others. And we're so tied up in passive music reception that there's no work involved anymore.

"I keep saying the next big thing in music has to be doing it. I think people are really hungry for it."

TIM ERIKSEN Saturday, April 25, at 8pm at Cayuga Vault, 1100 Soquel Ave., Santa Cruz. Tickets are $10 advance/$12 door; 831.421.9471; www.brownpapertickets.com. He holds a free shape-note singing workshop that day at 1pm at All Saints' Chapel, 2451 Ridge Road, Berkeley.

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