What began in 1980 as a Dixieland-only festival is now a showcase for many other musical idioms. This year, Dixieland Monterey’s Executive Festival Producer Al Pedersen is even bringing in Zydeco, and ace fiddler Tom Rigney. “Over time we’ve broadened our scope,” he says.

In the same way that rock is indebted to roots like rockabilly and blues, modern jazz is a descendent of what could be called roots jazz, namely ragtime, the blues and Dixieland, which developed in New Orleans around 1910. This year’s event visits three venues at Portola Hotel and will spill over into the Golden State Theatre. Connecticut-based pianist and 20-year festival veteran Jeff Barnhart is eager for that to happen. “Going back to the Golden State is exciting,” he says. “It’s one of the great gaslight-era theaters – the exact era as Rag and Dixieland. I can feel the ghosts when I’m playing there.”

In addition to appearing with his own trio and as a duo with his flautist wife, Anne, Barnhart will sit in with four of the event’s nine bands, in a number of settings, doing swing and boogie woogie with Carl “Sonny” Leyland, standards and swing with young pianist Jason Wanner, and straight-ahead Dixieland with The Crescent Katz and the Ellis Island Boys, two traditional New Orleans washboard groups. The Ellis Island band worked for Disney for decades and their grandmother was Zasu Pitts, a famous silent film star. “So they have some great old stories to tell,” Barnhart says.

With his other half, who is classically trained, Barnhart goes by Ivory and Gold, a nod to his piano keys and his wife’s gold flutes, which he says yield a warmer tone than the silver varieties. “Anne can play high notes by the dozen,” Barnhart says, “but when she gets those beautiful round low notes it almost feels like you could crawl into it if you wanted to.”

Another of jazz’s great traditions is the practice of players sitting in with one another, which is preserved here with Jam Cab on Friday and Saturday night. No festival badges are required for entry. “It’s really fun, and everybody has a wonderful time,” Pedersen says. “It’s a free, spontaneous open jazz jam.”

Given the open arms and diversified offerings, it allows for a lot of access points. Like Barnhart says, “You can truly say there is something for everyone and it’s not just empty hype.”

DIXIELAND MONTEREY PRESENTS JAZZ BASH BY THE BAY pre-event concerts 7pm Thursday; festival: 11am-10pm Friday, 9am-10pm Saturday, 9am-3pm Sunday, March2-5. Portola Hotel and Spa, 2 Portola Plaza, and Golden State Theatre, 417 Alvarado St., Monterey. Daily badges start at $45. 754-8786, www.jazzbashmonterey.com