Ivan Miranda’s MIDI Slapophone is a Mechanical Marvel of PVC and Motors

Fans of the Blue Man Group have frequently found themselves tapping their toes to the characteristic pounding sound of their PVC pipe instruments, which are essentially just slapping pipes of varying lengths with paddles to produce these rhythmically resonating tones that fill theaters. Ivan Miranda, a Spanish maker known for his ambitious 3D-printed creations, decided to take it a step farther. He decided to take the whole pipe-slapping thing and build a version of the slapophone that connects to MIDI, allowing you to control it electronically while still producing the physical slap sound.

Unlike typical slapophones, which require dozens of fixed pipes to cover a spectrum of notes, Miranda took an alternative approach. His design enables for telescoping assemblies, which are effectively numerous lengths of PVC pipe that move within one another. Each component of this instrument is built from four individual parts that nest together to form a compact quadruple extension system. Miranda painstakingly picked each pipe size, making sure the smaller ones slide into the bigger ones snugly , thereby keeping everything tidy even when fully extended. At the full extension, they can reach the lengths needed to produce those really deep low bass notes you want.

Its a motor-driven setup, with each motor giving it a smooth movement because of a toothed belt connected to a pulley. That pulley then pulls or pushes the inner pipe sections in and out smoothly. At the center of it all is an Arduino microcontroller, which serves as the operation’s brain, receiving MIDI inputs and calculating the exact lengths required for each note. With this brilliant invention, he was able to cover a pitch range of G1 to D3, or more than an octave of sound. Longer pipes provide deeper notes, and vice versa.

The only sound you’re going to hear when playing it is the physical thud of the pipes hitting together. The paddles are swung against the pipes using two stepper motors which he controls independently. Plus, they are constructed of layers of yoga mat material sandwiched between 3D-printed brackets, giving them both flexibility and a firm clean strike.

Playing this instrument is a bit more involved than just picking up and playing, but at a simple level you just need a MIDI keyboard spitting out note commands to the motors, which control the pipe lengths, and a drum pad to set off the slap. It’s pretty sweet. He divided the inputs in this manner to account for the time required to move all those hefty pipes around. Construction required extensive 3D printing; the brackets, adapters, frames, and pulleys were all created on his printer using nylon and common filaments. The primary construction is constructed of aluminum extrusions, with some great wheels to provide a smooth sliding.

However, early versions were a bit of a problem child in terms of resonance. Vibrations were dampened by the snug fit and solid mounts. So he experimented with pipe bends and softer mounting, eventually settling on several adjustments that improved the sound. It’s a power-hungry beast, and the entire equipment takes up a lot of space in his workspace. Amazingly, when someone sits down to play it, it produces true musical tunes.

Lou Wiss, a friend who came to visit, tuned up the pipes and recorded a few things on them, and was astounded by the recognizable sounds that began to emerge from the mechanical thumps. It demonstrates that, despite its flaws, this strange and beautiful machine functions properly. Miranda’s slapphone is a real mashup of old-school percussion with modern automation, a road few musicians have gone down.
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