By Jeff Woodard

It was just over a year ago that the widely-respected and nearly impossible-to-categorize guitarist Bill Frisell finally made his first appearance in Santa Barbara at SOhO, in a loose, beautiful duet show with bassist (and Santa Barbarban) David Piltch. The Seattle-based and internationally-revered Mr. Frisell made a more "formal" debut last week at the Lobero Theatre, with his New Quartet (one of his many projects), and it was a real dazzler.

Somehow, the term "formal" is a bad fit for music that so deftly celebrates the cross-breeding of genres and open-ended explorations of structure. Although he's generally lumped in the jazz world, from whence his career sprang, Mr. Frisell has long since moved in directions away from that music, at least in any strict understanding. He has delved passionately into country, folk, blues and world music (in the last year's album, "The Intercontinentals"), among other things. He leaves easy definitions in the dust, where they belong, according to his aesthetics.

True to form, Mr. Frisell's New Quartet, responsible for the 2001 album "Blues Dream," is a weirdly compelling mixture of rock, country, blues and experimentalism. There's a powerful chemistry here, between Greg Liesz's colorations on the pedal steel, lap steel and guitar, the sure, solidifying force of Mr. Piltch on acoustic bass, and drummer Kenny Wolleson's deceptively easygoing rhythm factory.

This night, they sounded at times like a thinking-person's extension of the jam band scene, but their band sound goes beyond that. With its loose and lanky vibe, the acoustic bass grounding, steel guitar cloudscapes and the unusual world of sound that is Mr. Frisell's guitar playing, it sounded at times like a roadhouse band from another planet. The theater was transformed into a surreal saloon-cum-opera house for a night.

Stylistic tags are worn loosely, and often shaken off, by the guitarist, including a sense of twisted "Americana." How else, though, to explain the mysterious ease with which Mr. Frisell wraps a new aura around the old chestnut "Shenendoah?" That was a highlight of the first set, opened with pensive introduction in drop-D tuning before the band joined in with its thick and dreamy ensemble feeling.

For an encore, Mr. Frisell traded his Telecaster for a hollow body jazz guitar to play the drawling Hank Williams classic "I'm So Lonesome, I Could Die," but that tune contained some of his most categorically jazz-flavored soloing of the night. Genres are always subject to change and mutation in Mr. Frisell's hands, as with the others. On a swampy number, Mr. Piltch played a melodically-driven solo, briefly quoting a fragment from the Weather Report tune "Birdland," and nobody flinched.

Mr. Frisell refuses to settle down into a strict identity other than his own voice, which can slip without warning from twangy touches in into bizarre loops from his effects. On the lumbering "Blues for Los Angeles," a solo suddenly got harmonically twisted, suggesting a slow motion John McLaughlin in the house.

The second set revolved around a sequence of cover tunes, including a pair of Bob Dylan songs- a bluesy recasting of "Masters of War" and a poignant instrumental recasting of "A Hard Rain's A-Gonna' Fall," in which the lyrics seemed to resonate in the background. Most surprising, though, was a cover version of Lucinda Williams' recent ode to escapism "Ventura," from her recent but already-classic album "World Without Tears."

One great thing about this band is its showcase for Mr. Liesz. He is an L.A.-based sideman of note, having worked with Joni Mitchell, on the latest Jack Johnson Browne album and, not incidentally, with Ms. Williams. But he doesn't get nearly enough credit, or stretching room, considering his unique artistry. Mr. Liesz and Mr. Frisell have a strong empathetic connection, partly because Mr. Leisz's slippery sounds on steel guitar (both pedal and lap) forge a kinship with Mr. Frisell's own elusive tones, conjured both through finger work and his subtle use of digital delay and other electronic effects on his guitar.

On the concert's final tune, Mr. Frisell's rambling (and chordally Dylan-esque) "That Was Then," Mr. Leisz took up his big Chet Atkins model Gretsch guitar to interact with Mr. Frisell. They didn't so much swap riffs as help to concoct an engaging collective texture, a key objective in this and other Frisell groups.

It must be reported that this group made for an ideal fit in the Lobero's intimate, historic ambience, given the group's inspired blend of musical aspects at once organic and plugged-in. It seems safe to say that Thursday's show was one of the trippiest shows ever hosted in this space-and in a purely artful way. Here's hoping that Mr. Frisell makes the Lobero a regular stop on his travels.