Author of the aforementioned thread here.

The hardware mod is the only solution for complete silence - the amplifier inputs will always pick up noise from something.

If you look at commercial DAC + amplifier ICs, they also mute the amplifier after a period of silence so it's a common issue.

@cbrightly https://github.com/macaba/ESP32AudioLibrary

Initial commit of ESP32/M5Stack audio library done. Not that many objects yet, I'll be adding more as time allows.

Yep! It'll be going on GitHub at some point.

It won't be compatible with the the original audio objects from the Teensy library;

1. I've moved over to float datatype for audio samples (it makes certain audio algorithms so much easier) so I've been slowly porting across the objects when I use them.
2. I've added some functionality that lets you get more detailed CPU reporting.

You can see my handy 'Amp on/off' control now:

Re: Noise on speaker

Hi all,

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! :)