You mentioned I need a "fast loop". If I dedicate so much CPU time to the audio processing, would there still be enough CPU time left to interface a WS2812b LED strip? (I think the protocol used by these LED strips needs very accurate timings.)
I just made an interesting find. This board has an ESP32 and a 3.5mm jack built in. I wonder if this would complicate or simplify things.
I guess the ESP32 has a much higher clock speed, way more memory and a higher resolution adc, but if I need to put a peak detector, between my audio source and the input jack it wouldn't really help too much.
Btw is a peak detector something you have to diy or can you buy it as an IC? Because it looks kinda complicated to build.
I will try to build the modified circuit with the schotty diode and take a look at your code example later today.
Thanks for taking the time! 