Re: Noise on speaker
I've been working on porting the Teensy Audio Library to M5Stack to allow full (& easy) audio synthesis.
However the background whine/hiss from the speaker when no audio is being played is very annoying (and quite loud on my M5Stack).
My suggested modification in this case is to put a wire from Pin 1 of the speaker amplifer to GPIO5.
Then it's just a simple case of
digitalWrite(5, HIGH); to turn on the amplifier, and
digitalWrite(5, LOW); to turn off the amplifier.
There seems to be a 30-100ms delay for the amplifier to turn on, and very little delay for it to turn off so I sadly can't get my audio library to automatically turn the amplifier on/off because I would miss the beginning of any new audio playback.
So I've just attached the amplifier control to
BtnA for manual control so I can at least turn off the noise.
Good luck to anyone else attempting this mod! :)