For Science!
5 Crazy Ways to Make Music with Technology

CJ Miozzi | 24 Sep 2014 15:00
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Strings, brass, percussion, woodwinds... yawn. We've been making music with these instruments for the longest time - but the last 100 years have seen the emergence of some new forms of instruments thanks to the advancement of technology. Here are five innovative ways to make and control music and the science behind how they work.

1. Lightning

We'll kick off this list with what is undoubtedly my favorite application of technology to musical purpose: the singing Tesla coil. Sometimes called the zeusaphone or thoramin after ancient gods of lightning, this mad scientist's contraption is a Tesla coil modified to serve as a plasma speaker.

There is no physical speaker here - the sound is produced directly from the electric arcs. Conventional speakers work by vibrating a physical diaphragm - generally a thin membrane - which in turn moves the air around it, propagating a sound wave. To use a simplistic example, imagine striking a bell, or tuning fork. While the object is vibrating, you hear a tune. But stop it from vibrating by touching it, and the tune stops.

How does electricity produce sound without a physical diaphragm? The same way a bolt of lightning does. When an electric current discharges through the air, be it as a bolt of lightning or as a man-made occurrence, the air through which it travels is near-instantaneously superheated into the fourth state of matter: plasma. By the gas laws we learned in high school, we know that an increase in temperature without an increase in volume results in an increase in pressure, so the electric arc is a high-temperature, high-pressure plasma channel. Since the air around this channel is of lower pressure than the plasma channel, the plasma rapidly expands into the surrounding air, producing a shock wave, or sonic boom, that propagates through the air - not unlike a physical diaphragm.

By modulating the spark output of a Tesla coil, you can control the precise pitch of the electric sonic boom and produce some rudimentary sounds - enough to play simple MIDI tunes, like from all our favorite retro video games.

Something that doesn't always come across in the YouTube videos is how loud zeusaphones are. Some measurements have placed the sound output of these behemoths at 120dB. To put that into perspective, sandblasting or a loud rock concert measure in at 115dB, and at 125dB, pain begins.

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