This is an audio visualizer built with p5.js.

I was jamming with a buddy one day and I thought it would be really cool to know what key he was playing just by looking at a visualizer connected to a microphone in a room.

I realized that if I take the FFT of a signal and slice it up into concentric circles that line up with the notes of the diatonic scale, you can get a pretty nice representation of the noise in the room.

After playing around with various parameters, I realized that this was a pretty cool music visualizer and that's pretty much what you see now. You can tweak various parameters in the sidebar:

• you can toggle the mode between song / microphone.
• you can toggle the view between polar and linear.
• you can toggle whether the octaves overlap or are spread out.
• you can toggle the grid that displays the notes.
• you can change the sharpness of the amplitude.
• you can change the gain.
• you can change the color scheme—the colors are deterines by anchoring a hue and sweeping through HSL for each octave.
• you can edit the opacity of each layer.

One thing that can use improvement is the FFT granularity. I'm using the 2048 bit FFT out of the box, I think with a custom script processor node you could probably build your own FFT that has much better granularity.

Here are some fun examples for you—click on the images to open up the visualizers with those presets.