The Vo-96 Acoustic Synthesizer is one of the most innovative musical instrument products created in years. Strap one onto any acoustic guitar and you can transform the way it sounds by breaking—or at least manipulating—the laws of physics. Here's the story of how inventor Paul Vo made a device that sounds like magic.


Vo is best known as the inventor of the infinite sustain technology inside the Moog Guitar. In one of its settings, if you strum the strings of that beauty, they'll keep vibrating forever. It's a hugely impressive technical accomplishment, but that's just a fraction of what Vo's acoustic synthesis technology is capable of.


The Vo-96 builds on those concepts and explodes them; it's a hugely sophisticated add-on for an acoustic guitar that basically transforms that old wooden box into an entirely new instrument. Depending which setting you're using, the Vo-96 can sound like everything from a violin to a woodwind to an analog synth.

Vo, 61, has been developing the technology for nearly a decade. In 2004, after 20 years of working in product development in the audio industry, Vo turned his sights to the vibration control technology behind the Vo-96. He says he'd been convinced the technology could work since 1979 but that it wasn't realistically possible until about 2000.

Vo moved to Raleigh, North Carolina from California, set up a lab and got down to work. In 2006, he first presented the technology to Moog in nearby Ashville, North Carolina as a gnarly but functional acoustic prototype. A cobbled-together electric prototype of the instrument came the following year after which Moog and Vo officially began the 18-month process of designing and building the Moog Guitar. The resulting instrument is a masterpiece of engineering inside and a work of art outside.



Now, Vo has turned his attention back to his orignal concept with the Vo-96, which he sees as the purest expression of his technology. Initially, the thing itself looks sort of monstrous, like, "How the hell am I going to attach this to my guitar?" There's a lot going on in this diagram below, but after you've installed the Vo-96 in a guitar, the only portion that's visible is the top user interface piece. The box containing the Vo-96's electronics goes inside the guitar's body.


You've probably heard an electric guitar make all sorts of crazy sounds thanks to either digital or analog processing. The Vo-96 works entirely differently, although technically the unit is doing both analog and digital backflips to alter the guitar's sound. Rather than modify the waveform after the fact—as in the case of an electric guitar and an effects pedal—the Vo-96 alters the waveform in real-time.

In other words, the Vo-96 changes the very physics of how a guitar makes sound to begin with. How do you do that? The device has what Vo calls a "two-way conversation" with the guitar strings. It listens to the strings and then applies a precisely calculated magnetic energy back to the strings to change how they sound.


The interface portion of the device contains 12 transducers, two for each string. The transducers take samples of the energy from the vibrating string, converts the samples into an electrical signal and then sends it down to the battery-powered controller box inside the guitar. The box computes precisely how much energy needs to be applied to each string, and sends that information back up to the transducers, which in turn do the work. That operation happens at a much faster rate than the string is vibrating, which means that from a practical point-of-view, the transducers are simultaneously listening and talking.

And, really, that description is an oversimplification of the technology. The Vo-96 has intensely granular control over the way the strings vibrate. You see, what it's actually doing is altering the vibration of 16 different harmonics on each string. (16 harmonic partials x 6 strings = Vo-96.) For each of those partials, the device can either apply more force or take force away. You can mute a particular harmonic, or you can sustain it forever—or at least for as long as you've got battery power.


Depending on which harmonics you alter and how you alter them, you get an entirely different-sounding instrument. For practical reasons, the first edition of the Vo-96 will come with just six preseets that you can tweak using three capacitive-touch sliders. You just can't build a simple user interface to modify all 96-possible control channels.


So this is just a fraction of what's possible. "Mother nature has been generous with this thing," says Vo. "It turns out that there is more sound in a string than I could have imagined in my head." The presets on the initial run of the Vo-96 represents what Vo thinks is interesting based on his own experimentation. But now, he wants to know what guitar nerds across the world think.


Information about the Vo-96 only just started trickling out about six months ago. Moog Music—which owns a license to Vo's technology—posted photos of a mysterious prototype codenamed "LEV-96" in last October. There were beautiful images of the kit and an enticing description of the technology, but it was still hard to understand what exactly the device was. And it wasn't until February that anybody actually heard it.


Today, Vo launched a Kickstarter to try to get 350 units of the Vo-96 into production. Kickstarter might seem an odd choice for a proven inventor like Vo. Indeed, the Moog Guitar has been a successful product for the company, and it's universally lauded; it took top honors at the music industry trade show NAMM when it was announced back in 2008. Despite Moog's enthusiasm for the LEV-96 prototype last fall, the company has no public plans to turn it into a product—or at least not into a product like the Vo-96. The company did a beta test-run of 12 LEV-96 units last year, but that was good old-fashioned research and development. Moog is a legendarily innovative musical instrument company, but it's got a bottom line to worry about, and in its current form, the Vo-96 isn't polished and ready for primetime.

Vo, on the other hand, isn't willing to give up so easily. "I was convinced there was a market for this even if it can't be a retail product," he says.


Vo constantly expressing his gratitude to Moog for their support on both the Moog Guitar and the Vo-96 projects, calling them "Total benefactors." But Vo's 100-percent committed to developing and advancing the vibration control tech, and the two parties mutually decided that he should go off on his own and develop the concept further. That's what the Kickstarter is all about—funding additional R&D with manufactured, fully functional units as it has been developed so far. (Earlier today, Moog issued a press release inviting people to contribute to Vo's Kickstarter.)

He says he wants to get the Vo-96 out there to see what a larger test audience would do with it. From there he can make modifications to the software for firmware upgrades and to the hardware for future iterations.


Getting a Vo-96 won't be cheap—between $1050 and $1450—depending on when you sign on to the project. The money from the Kickstarter campaign would go to paying for the components for the initial product launch as well as to accelerate software development. It's been a long wait already, but it still can't get here fast enough.


[Kickstarter and Vo Inventions]