Though no one is making much of it, an era is coming to an end.

For the past 20 years, Jeff Kaiser — trumpeter, composer, electronic voyager, record label owner and impresario — has almost single-handedly given Ventura a sizeable new-music profile. And when he presents his Ockodektet at Ventura City Hall on May 26, it will signal his farewell to the city.

“I’m entering a doctoral program at UC San Diego in the fall,” Kaiser says, speaking from the Experimental Music Festival in Boise, Idaho. “John Fumo, the trumpeter, went on tour and I took over his classes at Cal Arts for a month. And I discovered I really love teaching at a university level. I’m 45, and it’s time to get my higher degree.”

Kaiser has made Ventura a viable link in the San Francisco-to-Santa Cruz-to-Santa Barbara-to-Los Angeles itinerary of experimental, avant-garde and left-of-center musicians of almost every shade. One such performer is poet Dorothea Grossman. Grossman works in tandem with trombonist Michael Vlatkovich, who improvises musical epigrams while Grossman reads her humorous and heartfelt poems. It is a highly specialized format and a hard sell to bookers. Yet Kaiser has not only presented the duo live, but released their recordings on his pfMENTUM label.

“Everything Jeff does is musical,” Grossman says. “Nobody works harder. He’s not happy unless he is overworked — with students, running the label, booking concerts and preparing music. He has put Ventura on the map as far as new music is concerned.”

“He has the ability to realize music in a very short amount of time — to compose it, rehearse it and present it — and that’s quite difficult to do,” Vlatkovich adds. “It’s particularly hard with a large group, and to have control over the group. But Jeff has absolute trust in the people he assembles. It’s a given that they can play, but there are other issues to consider: Will they like each other? Will they pull together as a unit? Did one of them get a parking ticket that day? The dynamics can be so difficult. Jeff knows how to pick people and make their weaknesses disappear and bring out their strengths. It’s truly fascinating.”

Percussionist Brad Dutz, who has recorded 10 albums for pfMENTUM, is continually intrigued by Kaiser’s compositions. “His writing features a lot of colors, and he uses graphic notation in color. That makes all the musicians think more about what they’re going to play. Plus, he’s got all this knowledge about electronics, which he feeds through the trumpet: processing, digital delays, reverb pedals.”

“Jeff’s not afraid of that technical world,” says flute virtuoso Emily Hay. “He combines the composition and programming aspects of his music with the technical ability. He’s expanded his sound palette and I admire that.” Hay is also grateful for the recording opportunities Kaiser has provided. “His concept was to create a communal collaboration among Southern California musicians so their music can be heard. With pfMENTUM, all of this music is in one place, and with it, we have a collaborative presence. We know people are listening from the e-mails and responses we get. It’s reached as far away as Siberia and Macedonia.”

Kaiser will be working in town — mostly with students — for a few months, “courtesy of the I.R.S.,” he jokes.

“I have a lot of mixed feelings about leaving,” Kaiser admits. “I walk down the street and I see people I know everywhere. I produced my first concert here 20 years ago. Ventura has allowed me to grow organically in a way that I couldn’t in New York or L.A. It’s allowed me opportunities to develop as an individual, without the circle of influence. My degree will be in Critical Studies and Experimental Practices. Ventura allowed me to think like that.”

What animates Kaiser, the composer-player? “I get an idea stuck in my head,” he enthuses, “and I feel compelled to do it. I just want to be able to hear my ideas. I want to create these other worlds that I hear. I think that the world of the psyche is every bit as compelling as the physical world.”

“Michael and I have a running joke,” Grossman says. “We say that Jeff Kaiser is actually the secret mayor of Ventura. Otherwise, how would he be able to do all the things he’s accomplished?”