MUSIC TUCK AND PATTI : Vocal Marriage : They’re a husband-and-wife singing duo who specialize in interpreting the American song.

Some of the finer things come in small packages. A case in point is Tuck and Patti, now dancing all over the jazz charts. This duo--joined both in music and in wedlock--achieve an intimate chemistry and put on a full-bodied show, giving equal weight to improvisation and the celebration of the American song.

They’ll demonstrate what makes them tick for the first time in Santa Barbara at the Lobero on Aug. 24.

Just one question: Are they a jazz act? Yes and no. The third and newest album, “Dream,” for instance, covers a lot of ground--in and beyond the realm of jazz. They swerve from the anthemic original title track to the lush Bernstein-Sondheim ballad “One Hand, One Heart” to a Wendy and Lisa pop hit, to a solo guitar version of Stevie Wonder’s “I Wish” to the reggae chestnut “Sitting in Limbo” to the spunky a cappella “High Heel Blues” to “As Time Goes By.” How dare they?

Yet it all coheres nicely, and the proof is in the artistic packaging. Guitarist Tuck Andress packs a punch. He has an encyclopedic approach to music in his rhythmically charged guitar style, but retains a warmth and friendliness. “Reckless Precision” was an apt title for his solo album of last year. Patti Cathcart, meanwhile, wriggles her way around their diverse repertoire, working as much out of soul and blues traditions as jazz.

It all began innocently enough in San Francisco in the early ‘80s, when the duo formed to play in nightspots and quickly became a local favorite.

Opportunity--a deal with Windham Hill Records, to be exact--came knocking. The label saw in them a dynamic act capable of tapping the pulse of a new jazz audience, weaned on pop, soul and other non-jazz idioms, that likes variety in its diet.

Immediately after their debut, the happy couple took their act on the road and they haven’t gotten off it much since. They spoke on the phone from a stop in Milwaukee. On conference call, of course.

Your albums have had this seemingly careful balance between jazz standards, latter-day pop standards and a few unexpected things. Do you design albums that way?

Patti: They’re not real thought-out until it’s time to do them. I like to approach records freshly. When the project is ready to begin, then we stop everything but that.

The order of the album takes shape as the album starts being recorded. Songs we thought might have gone on there don’t wind up happening, and others find their way in. But we just take things from different places. We still haven’t gotten to all the areas we’d like to get to. We’ve never really gotten to the Latin side of it. That will come up at some point.

You now have this three-album discography. It must change your perceptions. It becomes your signature, in a way, doesn’t it?

Tuck: We’re used to all the music not really existing outside of our performance of it. Now, in people’s minds, their idea of Tuck and Patti is what they hear on the records. Our idea of Tuck and Patti was always whatever we happened to do that night. Of course, people who came back had certain favorites and would request them, but it’s nothing like it is now.

Patti, how did your tune “High-Heeled Blues” come about?

Patti: I like that tune. That’s an improv that’s developed over the years. It used to be a Latin song and has been all sorts of things. Tuck would play and I’d just start singing along and make things up. Over a year ago, it became an a cappella song and then it became a cappella blues. That day, I recorded three versions of it and that version seemed the funniest to me, so that was the one we used. But it was always different.

Tuck: Because of the process we were talking about earlier, where the discography takes on its own life, now that version exists as a fact of life in people’s consciousness.

What you are doing is, on one hand, pretty unconventional, but also a great forum for presenting songs. Was your emergence a matter of good timing?

Patti: I think it had everything to do with it. It was during that time when all those networks, the “Waves” and “Breezes,” were coming out. Those played a crucial part in (certain) acts getting through during that time. We happened to slip through one of those windows of opportunity.

It seems that, after all this time, you’ve developed a sense of telepathy together. Is that true?

Tuck: It’s getting there. We do certain things that probably seem telepathic, like we don’t count tunes off--we just listen to each other breathe, even when we’re starting on the same beat. But I think there are plenty of surprises. And there are plenty of times when Patti is hearing it one way and I’m hearing it another and go off somewhere, and we meet somewhere on the other side.

Patti: (Laughs) Sometimes we meet where we least expect it. That keeps it exciting 13 years later, that’s for sure.

Tuck: At our worst now, we sound better and more coherent than we probably did at our best at some earlier point. So even on bad nights, people don’t really know when we’ve gone astray.

Live music is the thing for you, isn’t it? Is that where you feel your best expression lies?

Patti: Well, I love working in the studio, but there just isn’t anything like live playing. In performance, there are people there, and that’s what causes that magic to happen--all that combined energy.

* WHERE AND WHEN

Tuck and Patti will play at the Lobero Theater, 33 E. Canon Perdido St., Santa Barbara, at 8 p.m. Saturday. Tickets are $17 and $19. For information, call 963-0761.