But when I heard it played, I realized there's a loud clack every time a note is sounded. I think it's produced by the solenoid that's opening the teeth — but since it sounds like the CLACK of creepy horror teeth, it adds a nicely (and fittingly) crepuscular element to the project.
Better yet, the clack is timed not with the closing of the mouth but with its opening, which is somehow yet more freaky.
VOC-25 is a conceptual vocal synthesizer based on the Axoloti Core and 25 sets of plastic teeth, each set representing a unique note on the keyboard. The three-part wooden setup echoes the look of a classic desktop computer including monitor, main console and keyboard. RAW vocal audio samples are fed into the main console via USB, creating a personal voice bank. There are two built-in effects, reverb and delay. The Axoloti board inputs MIDI via the 25-key keyboard, but it also outputs MIDI. These signals are converted to DC current via control boards located inside the monitor segment. The custom-built boards direct the "choir" – 25 individual solenoids, each one connected to a set of hinged teeth. The setup can be used standalone with its built-in speakers, but it also outputs mono in the back, and using external monitors is a good way to reduce mechanical noise.