This is a port of my audio monitor for the ESP32 (https://github.com/atomic14/esp32-tft-audio-monitor) to the WIO Terminal.
There's a couple of changes. The biggest change is that the samples are now collected using a timer instead of DMA transfers. It is possible to set up a DMA transfer to read from the Wio's microphone, but I wanted to keep this code as simple as possible.
You'll need VS Code and the PlatformIO plugin installed. It should just build and run.
Press the five-way button to toggle the different visualisations.