This Animal-Shaped Glockenspiel Is Really a Rad Experiment
The Zoolophone is a glockenspiel with keys shaped like zoo animals. It’s adorable, right? Turns out it’s also a pretty cool engineering experiment.
Although it looks like a children’s toy, the musical instrument is the result of two years of research by professors at MIT, Harvard, and Columbia universities. They wanted to know how they might use a computer algorithm to develop shapes that produce specific frequencies and vibrations. The idea is that by learning more about how shape impacts sound, designers could create quieter fans, bridges that don’t amplify vibrations under stress—oh, and neat musical instruments.
Like xylophones and glockenspiels, the Zoolophone is a metallophone, an instrument with tuned metal bars that produce sound when struck. The tone and amplification a metallophone make depends on the shape of the instrument itself. Most metallophones require hand-crafting to get resonant frequencies and amplification just right—they use rigid geometries (like bars) and hand-drilled dimples on their undersides that allow them to create predictable sounds.
The researchers wanted to know if they could automate (and simplify) the process by which a customized metallophone is built. By coming up with a desired form, then setting a list of parameters (think height, width, thickness, material), was it possible for an algorithm to create a shape that would produce a chosen amplitude and frequency? “A lot of parameterizations we use in this project are things that anyone who uses Photoshop or Illustrator would be familiar with to change an image,” says David Levin, a researcher at MIT and Disney Research. “We just apply them to explore this soundscape computationally.”
Levin says the first step is to choose a desired shape—in this case, animals. From there, the researchers set algorithmic parameters that allowed the software to perforate and deform that shape to achieve a specific tonal quality. This isn’t unlike the conventional process in which humans tune instruments by creating indentations and altering the geometries of the instrument’s bars. The difference, Levin says, is a computer can cycle through far more designs at a much faster rate. “It lets you find designs that have much better performance than one could find manually,” he says.
The downside, of course, is you can’t have everything you want. Achieving a particular sound requires concessions when it comes to the aesthetics of a shape. Just because you want your E note to look like an elephant doesn’t mean the elephant will produce the most beautiful note—the algorithm might clip the trunk or deform the leg to produce the desired sound. “There are tradeoffs,” says Wojciech Matusik, another MIT researcher on the project. In the end, you have to choose what you value more: the shape or the sound.
So in the case of the Zoolophone, does the form (i.e. the desired animal shape) dictate function (i.e. the sound), or vice versa? Levin says that, in the case of the elephant, form won out, resulting in a bar that sounds just a little off. When the bar was made to ring in tune, “it looked way too much like an anteater for everyone’s comfort,” he says. “If you want to preserve elephant-ness, it does come at a cost.”