Experimental music, by its nature, is hard to define. That’s because many of the artists who make it cross so many boundaries and work with the intention of creating an experience rather than adding to a defined repertory. Among such innovation-minded contemporary artists, Trimpin — the sound sculptor, composer, engineer, and inventor — is one of the most renowned.

Known in North America and Europe largely for his multifaceted installations, the 73-year-old creates his own instruments — often out of found objects like old Dutch clogs, toys, beer bottles, saw blades, and electric guitars — and animates and controls them via MIDI (Musical Instrument Digital Interface). Trimpin has been the recipient of numerous awards, fellowships, prizes, and commissions, including a 1997 MacArthur Foundation “genius” grant. His latest project, The Cello Quartet, will be presented at the 28th Other Minds Festival, which runs Sept. 25–28 at San Francisco’s Brava Theater.

The Cello Quartet features three cellos (without musicians) perched on separate platforms that move around the stage, another platform with a live cellist on it (rounding out the quartet), and another with a piano. Several live dancers, choreographed by Margaret Fisher, will be interacting with the moving instruments like circus performers. The production was made possible through a generous grant from the Hewlett Foundation.

Lori Goldston, the human cellist in the piece, said that she didn’t know Trimpin personally until he approached her about the project. While Goldston is no stranger to collaborating across genres, she said that working with him has been a “pretty unique experience” and described him as being full of curiosity.

“It’s been delightful working with him. He is a trusting collaborator, and his work is packed with joy and humor,” said the Seattle-based cellist. Of taking on a role in The Cello Quartet, she added, “I’m inclined toward improvisation and usually steer clear of backing tracks, looping, and other fixed sound sources, so working with MIDI-triggered sources is a big switch from my usual contexts. I’m an ultra-organic foil to the machines.”

Born in a small town in southwestern Germany, Trimpin grew up in a place where cuckoo clocks and other coin-operated entertainment machines could be found everywhere, and these fascinated him at an early age. He was exposed to live music because his father played in a brass band and gave music lessons, and there were many brass instruments around for the young artist to play and tinker with.

“When I was playing the trombone, I was not satisfied with the monophonic sound which came out of it,” said Trimpin. “So I actually added a second bell to have the polyphonic capabilities available, making sound with multiple notes and tones. I had a hacksaw and cut the trombone apart, and everybody always said, ‘You shouldn’t do this.’ But my parents didn’t complain, so it was OK.”

Eventually, Trimpin developed a curious allergy to the brass instrument and had to quit playing, which triggered his desire to experiment and create his own instruments. After moving to Berlin to attend university, he apprenticed as an electromechanical engineer and began working as a set designer, going “more in the direction of experimenting and working with sound sculptures,” he recounted. But he discovered that Germany was less hospitable to his practice, so in 1980, he decided to move to the United States. He settled in Seattle to continue his work. His first few years there, he worked occasionally on a fishing boat in Alaska to make ends meet.

“For several years, I was going off for one month on a fishing boat and fishing for salmon or herring, and you could make enough money — usually $10,000 a month in the early 1980s. But then I got hired by the [Sweelinck Conservatorium] in Amsterdam for three years, and then after that I was ready to go back to Seattle and work in my studio.”

One of his early grants came from New Langton Arts, an artist-run organization located in San Francisco from 1975 to 2010, for which he developed several new pieces.

In 2007, Bay Area filmmaker Peter Esmonde was searching for a unique artist to be the subject of his first documentary feature, and he chose Trimpin.

“I was looking for someone who spanned several artistic categories and ideally who did something visual and audio because in a film you need both,” said Esmonde. “And also somebody who was well regarded by his peers. So I just kept asking friends who were artists and musicians … and the name Trimpin came up. At the time, various arts organizations in Seattle were getting together to do a multi-venue retrospective of Trimpin’s stuff, and I thought, ‘If I am going to make a film, now’s the time to do it.’ I had the opportunity to film him assembling a number of works.”

The film, titled Trimpin: The Sound of Invention, premiered at the 2009 South by Southwest Film Festival and was shown at a number of other festivals as well. It beautifully captures Trimpin working on various projects in his studio, including a collaboration with the Kronos Quartet.

Esmonde said that working with Trimpin was terrific. “He is unique. Among people who know certain kinds of contemporary music or are very interested in certain kinds of kinetic arts and kinetic sculpture, he’s a real touch point.”

Trimpin’s work has been inspired by many experimental composers, including John Cage, Henry Brant, and Samuel Conlon Nancarrow, who was known for writing pieces for player pianos more complicated than a human could play. Trimpin met and befriended Nancarrow in 1980, working and collaborating with him until the composer’s death in 1997.

Charles Amirkhanian, executive and artistic director of Other Minds, which has long championed new and experimental music, has known Trimpin for many years and chose him to be one of the artists at the very first Other Minds Festival in 1993. An accomplished composer himself, Amirkhanian enthused, “One of my greatest discoveries was meeting Trimpin. This guy’s a MacArthur Fellow and an inventor of unbelievable talent. There are other people inventing instruments, but he goes beyond just making them. He actually figures out inventive ways to employ them in compositions. He wants to make sounds that aren’t electronic but are acoustic and controlled by computers though some sort of elaborate mechanism that produces the event that gives you the sound.”

Trimpin spent several years developing The Cello Quartet. And though he’s an old hand at creating innovative and original installations, he believes that this new project includes some things he has never done before.

“The kind of idea in my work with music [had always been] dealing with three parameters — timbre, pitch, and time,” said Trimpin. “But my interest [became] to give it a fourth dimension or parameter — adding space, movement, and motion. The Cello Quartet basically is three autonomous [cellos] and one live cello actually moving onstage while the music is playing. So everything is in motion and that’s adding the fourth dimension — the spatial imaging into a performing art where all four dimensions are a part of it.

“Also, in the first movement, I developed a system for the piano. Right above the piano strings there are some coils, and when the coils are energized, they bring the strings into vibration, without touching them, through a magnetic field. And this sound, which is based on the first 11 harmonic pitches, starting with a low A and going through 11 harmonics, will be transposed up 42 times, and then we are into the spectrum of light. So the colors you will see projected on the back of the stage are actually generated from the sound from the piano.”

When asked if the music at the festival, including Trimpin’s, is a bit way-out for the average ear, Amirkhanian explained Other Minds’ philosophy:

“There’s no way for people to find out about it except by going. One of the things that Other Minds tries to do is to find the music that speaks to people who don’t necessarily fixate on what’s the latest but want to enjoy themselves and hear something that’s a little bit more challenging and will expand their consciousness slightly. So we try not to do things that are so innovative that they make you deaf or they make you never want to go out of your house again — and there are people doing music like that. But we try to find the sweet spot where there’s innovation, intellectual capacity is challenged, and something beautiful results.”