In the Adafruit forums, user Govner shows a sound reactive project using a pair of Adafruit Trinket M0 boards to perform light synchronization to sound.

In a nutshell, the project requirements were to produce a audio-frequency detection (with 3 Hz resolution) and color matching unit, for driving 5050 LEDs (Neopixel 24-ring or strips) reactive in real-time. It’s software options provide for simulation of all sorts of audio/color reactive displays. For example, in the “Close Encounters” mode, one can play the actual Hollywood production trailer for the famous “audio conversation exchange” on Devil’s Mountain and the Neopixel ring mimics the light segments of the mother ship — lighting specific colors and shades matching octaves and tones during the segment. This mode is but one of many. Bass guitar modes are cool as are specialized flower vase effects (pedestal mode).

And the Trinket M0 is the center of it all:

I just couldn’t be happier with the flexibility made possible using these Trinket M0s and C++ to yield the powerful math functions and effects needed to make this such a dynamic unit. It wasn’t cheap. The R&D was quite expensive as I am sure all developers are well aware. I wanted to just say how impressed I am with the Trinket M0s reliability and ease of implementation.

A demo is shown in the video below. You can read about the entire project in the Adafruit forums.

Each “Rainbow Pedestal” is currently frequency locked to the quartz singing bowl show (Note F, 4th octave) just for demonstrating the sensitivity of these units. Keep in mind that each “pedestal” will have its own singing bowl (unique note) and the color corresponds to “conventions” that will illuminate when that particular bowl is “singing”. I know, it’s confusing but here’s a little eye-candy demo. Each pedestal contains 2 Trinket M0s as well as the 24-ring WS2812s. (Plus lots and lots of other stuff).