By Cooper Wentz
What drove me to make the Acousonix Hammer was a conversation I had with Bryan Galloup and several forward-thinking colleagues in the industry. I was reflecting on principles preached by my favorite inventors and entrepreneurs: domesticating, demystifying, and simplifying complex processes until only the essentials remain.
I had always envisioned a setup that included expensive FFT analysis software, a computer, a high-quality external microphone, a voicing jig, and a guitar. Even then, you still needed a tapping tool, either a hammer or a finger, to ring the guitar out properly. Then I realized I could embed the FFT engine, the microphone, and the computer circuitry inside a single hammer. That idea would make an excellent teaching tool because it strips away all the extra setup and focuses students on one simple action.
With the Acousonix Hammer, students immediately see what is happening inside a guitar. The hammer contains a small computer, a condenser microphone, and a readout screen. When you strike any object, it runs an FFT analysis to isolate the dominant frequency, and that number appears on the display. The device then waits for the next loud sound before repeating the analysis.
In practical terms, the hammer tells you an object’s natural frequency. Tap a window and you see its loudest vibration frequency. That measurement dictates our perception of pitch and defines the character of the sound. By reducing FFT analysis to a single most important number, the tool becomes remarkably approachable.
On a guitar, striking different spots reveals different resonances: hitting the top plate shows its dominant frequency; tapping near the sound hole measures the air resonance; striking the back or the shoulder region reveals their primary frequencies; even an isolated, uncoupled top plate registers its inherent frequency. If you love a guitar that rings at 160 Hz, you carve your next build until the top plate reads 160 Hz, and you have effectively replicated the instrument’s voicing.
Developing the Acousonix Hammer involved a lengthy discovery phase full of learning curves, late nights, and more than a few head-banging moments. Performing a full FFT analysis on a tiny microcontroller proved tricky. Adding all the features I wanted without any buttons was even more challenging. My goal was a tool that simply powers on when you hit something and immediately shows the frequency. Achieving that goal required ten to fifteen prototypes, each with different microcontrollers and quirks to iron out.
Getting the computer to identify the true dominant frequency meant implementing a major peak algorithm. Once that was working, I shifted to handcrafting every unit: wiring, sanding, three-dimensional printing, and finishing every part manually.
Each condenser microphone has adjustable gain, so I set the gain for each one by hand with a screwdriver to compensate for slight electronic variations. I solder every wire into each microphone myself while a 3D printer produces the custom enclosure parts.
Next, I wire up the readout screens and braid the leads in a helical pattern to reduce electronic interference. Each enclosure is lightly sanded so the screen snaps in without cracking. I secure screens with precise drops of glue in the corners, just enough to hold them during assembly. Then I wire each battery pack and the USB-C charging port, braid those wires up the handle, and glue each braid so it never unwinds.
To finish the handle, I apply wood glue and sand through progressively finer grits—sometimes up to 1,000 grit—then dust fill any seams. I use exotic hardwoods such as Amazon rosewood. Each handle is buffed, and I scuff the glue-joint areas so the new glue adheres properly. That completes the handle shaft, where a cap protects the recharge port and the hammer head attaches.
I assemble all the components for the hammer head and the striking structure using a polymer compound that feels like a firm eraser. It compresses under impact, exciting the guitar without harming lacquer or polyester finishes. I hand shape and sand each tip, then apply a feed and wax finish, plus a micro wax coat over the entire hammer.
The result is a teaching tool that makes voicing and basic acoustic analysis far less daunting. Instead of overwhelming students with desktop FFT software, external microphones, and complex setup instructions, they simply hit the guitar and read a number. If they like how it sounds at that frequency and if guitar shape, dimensions, and materials remain consistent, they carve their braces until the hammer reads that same number every time. It is a simple, direct lesson.
Even advanced luthiers such as Bryan Galloup have found the Acousonix Hammer phenomenal. He used it on the fly while evaluating tonewood sets in Italy and Switzerland, rapidly testing hundreds of samples compared to older tonal-analysis methods. Banjo makers, violin builders, and acoustic researchers have also embraced it for faster voicing, tuning, and exploration of instrument acoustics. In every case, the Acousonix Hammer transforms a once-complicated workflow into a simple, intuitive process.
For more information about the Acousonix Frequency Hammer, visit https://www.galloupguitars.com/the-acousonix-frequency-hammer/