This video demos an audio spectroram on the M5Stack Core2.
It was obtained as firmware downloaded from the M5Stack Burner. Select Core2 and then the demo Audio Spectrum.
It uses the Core2 microphone to capture ambient audio and LCD to display the spectogram.
Ref:
* M5Stack Shop: Core2 (https://m5stack.com/collections/m5-core/products/m5stack-core2-esp32-iot-development-kit?variant=35960244109476 )