Plasma Speaker (Tesla Coil)

There are some things that go against conventional wisdom and make you scratch your head and ponder how it does that.

While skimming through AliExpress, I came across a product touted as a “Tesla coil music speaker,” which felt like a mislabel. Then I read the product description:

“Can play mobile phone / computer music, the sound quality is clear. 15 to 24V DC, arc length 24V 5–10mm is the most ideal, small volume, complete work and energy, can work continuously for a long time, still can with LED light from a distance, the milk bubble energy-saving lamps, flash frequency control, can play radio transmission, rotating arc, etc.”

I know, right? With a description as detailed as that, you just have to have one. I quickly added it to my cart, checked out, and patiently waited for it to make the long journey from China to my home.

Here’s a video of me assembling and testing the device:

There is real science behind this, and it is not a new phenomenon. Whereas a conventional speaker uses a diaphragm to change air pressure, the Tesla coil uses high-energy electrical plasma. A modified solid-state Tesla coil modulates the spark output, resulting in a low-fidelity square wave output similar to an analog synthesizer.

You can learn more from these Wikipedia articles: Singing Tesla Coil and Plasma Speaker.

This kit was a lot of fun and took less than an hour to solder and assemble. I recommend it to anyone with an hour or two to spare — it makes for a great party trick.