The Journey to Build a Six-String Acoustic Cello with Luthier Trevor Davis and Player Geoff Manyin

A six-string acoustic cello would allow for greater range of tone, though building one would definitely pose challenges

By David Templeton | From the January-February 2024 issue of Strings Magazine

When cellist Geoff Manyin of the Austin-based quartet Invoke gets together with his longtime friend and master luthier Trevor Davis, also of Austin, the two self-described “Scotch heads” enjoy sipping fine Scottish whisky, talking about music, and brainstorming together on what the ultimate musical instrument might be. “Trevor is best known for making double basses, so he and I were able to bond over our love of the low tones,” explains Manyin, whose work with Invoke has drawn acclaim for its playful, unstuffy approachability and entertaining musical invention. “And at some point, probably over some whisky, we dreamed up the idea of making an acoustic six-string cello.”

Though some electric cellos do have six strings, acoustic cellos have been sticking to four strings for the last 500 years or so. A six-string acoustic cello—something like a viola de gamba, which can have six or seven strings—would allow for greater range of tone, though building one would definitely pose challenges. “It was the kind of thing where you go, ‘That’s a cool thought, but I don’t know if we’re really going to make that happen,’” Manyin admits. “A few years passed, and the pandemic was in full swing, which led to some changes in Trevor’s workflow, and one day he gave me a call out of the blue saying, ‘Remember that thing we were talking about? The six-string cello? I think I might be interested in making it now.’”

Trevor Davis Six-string cello
Trevor Davis Six-string cello. Photo: Zachary Matteson.

As Davis recalls it, the idea had been alive in his mind ever since those original conversations. “It was a wild idea, man!” Davis says. “I knew I’d have a blast making it, and Geoff thought it would be a cool instrument to have. Once I finally got serious about it during Covid, we’d sit out on the front porch and talk about what he really wanted from it. Would he really use the full range of it, with a low F chord? How would it need to function for him, physically? Building the basic instrument was easy enough, but the real work kicked in when it came time to set up the six-string part of the cello—and just getting the strings made was really difficult.” 

For those custom strings, he turned to the engineers at the Austrian string and rosin company Thomastik-Infeld in Vienna. “They really came through,” says Davis. “They only have so much machinery, and only so much time on those machines, and I’m sure they have a lot more important things to be doing than making a cello low-F string. It took the better part of a year. I ordered four of them, four F strings. But once I got them, wow! The darn thing sounds like a bass. It was like Dorothy stepping into Oz, a whole new world opening up in Technicolor.”


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As for the challenges of getting the setup on the cello right, Davis said there were bow-clearance issues and string-crossing issues to address, all so Manyin could comfortably and effectively play the instrument. He had to build the tailpiece from scratch, and engineered the scroll to be extra strong, with a carbon-fiber rod down the center to help withstand the extra string tension brought on by the additional strings.

“It was a lot,” he says. “But who doesn’t love a challenge?”

The goal, of course, was to end up with an instrument that Manyin could actually play—and possibly record with. “Getting the cello so he could really lay into that C string—because cellists really like laying into the C string—while still being able to have nice clearance on the F string, that took some work,” Davis recalls. “Getting all of that figured out so it was nice and balanced, that took some work.”

Trevor Davis Six-string cello
Trevor Davis Six-string cello. Photo: Zachary Matteson.

Much of that work took place after the instrument had been completed and delivered. “There was a lot of tweaking and changing,” Davis says. “We went through a couple of different bridges. There was a lot of experimentation.”


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Because Davis’ shop is in the same town where Manyin lives, the cellist could simply drive to the other side of Austin whenever he realized the instrument needed something. “I’d basically show up, hang out, do some play testing,” Manyin says. “I’d say things like, ‘So, this is great, but maybe there could be a little more room to dig into the low strings,’ or I’d ask about messing with the bridge angle or something. It was a lot of fun.”

Some of what Davis learned from the project has become useful in his regular instrument-making work. “I’ve been experimenting for a while with making smaller basses, because sometimes smaller players ask for that,” he says. “Getting a smaller bass to sound as big as possible is the goal, so I can use a lot of what I learned from building Geoff’s cello.”

After a couple of years with it now, Manyin says the six-string has become the primary cello he plays on. “It’s a real cool instrument,” he says. “It’s a little quieter than a standard cello, because of the thicker fingerboard and tailpiece and everything, but the extra range it gives me is really awesome for the kind of music we play in Invoke. We’re able to compose for it and really take advantage of the lower tones, which are normally part of the double bass world.”


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Allowing that he is still growing in his understanding of how to get the most out of the instrument, Manyin says that playing a six-string cello requires adapting physically to its unique characteristic and ergonomic requirements. “As it is currently setup, playing on the high E string is very difficult, because the margin of error from my angle of attack is basically zero,” he says. “So, I’ve developed a technique with my left hand of muting the neighboring strings. That way, I can play one note at a time when needed. There’s also a bit of extra arm weight required when hitting the low string. So, it’s a bit of a balancing act, but it’s been a fun adventure.” 

Trevor Davis Six-string cello
Trevor Davis Six-string cello. Photo: Zachary Matteson.

Asked about the possibility of making more six-string cellos in the future, Davis doubts there will be much demand, but if there is, he’s more than ready to make another. “I don’t think there will be many people who are interested in a six-string cello, but of course, I’d love to make another one for somebody, if we were on the same page about what everybody wants,” he says. “That said, I want to make instruments that people will really play, not sit in a corner somewhere gathering dust. What I love about Geoff’s cello is that he actually plays it. He’s recorded with it on Invoke’s latest album. He really uses it. That’s just really cool.”

Asked a similar question about the chances his instrument will inspire other players to tackle the musical adventure of playing the six-string cello, Manyin thinks he might be in a one-of-a-kind situation. “With this instrument, while I certainly am grateful that it exists—and while I think it’s worth having for what I do—it has made me realize that, yep, the work that all of those people have done over the last few hundred years to perfect and refine classical instruments makes sense. Having four strings does seem like the sweet spot for most people. But who knows? Anything is possible.”