Analogue spectrum analyser

Audio is a huge, deep, twisty rabbit hole of expensive gear, performance optimisations, and indecipherable jargon. And that’s what makes it fun. If you’re at all into audio, this ten-band frequency analyser provides an easy, graphical way to show you exactly what’s going on when you’re listening to the latest Taylor Swift LP.

You can roughly divide this project into the pretty bit, the clever bit, and the very clever bit. For the pretty bits, the maker used addressable RGB LEDs, 10 mm thickness transparent acrylic to diffuse the light from the LEDs, and black acrylic to provide a background. The clever bit is the ESP32. The very clever bit is the custom PCB designed by emdee410, which makes everything possible. The exact details are beyond us, but we do know that the circuit is analogue, with each frequency band having been given its own op-amp rather than having frequencies broken out digitally.