Issue: ReSpeaker Lite Produces pulsing White Noise Using AudioTools for I2S Loopback mic > speaker

[rightup]

Problem Description:

I’m using the to set up a simple I2S audio loopback on the ReSpeaker Lite. The goal is to read audio from the microphone (I2S input) and output it directly to a speaker (I2S output). While the audio is played, it alternates between the expected audio and bursts of white noise in a repeating pattern.

My Setup:

• Board: ReSpeaker Lite (ESP32)
• Library Version: AudioTools latest release
• Sample Rate: 16000 Hz
• Audio Configuration: 16-bit PCM, Stereo
  • Pins:
  • BCK: 8
  • LRCLK: 7
  • DATA_OUT: 43
  • DATA_IN: 44

Console logs:

I] StreamCopy.h : 158 - StreamCopy::copy 1024 -> 1024 -> 1024 bytes - in 1 hops
[I] StreamCopy.h : 158 - StreamCopy::copy 1024 -> 1024 -> 1024 bytes - in 1 hops
[I] StreamCopy.h : 158 - StreamCopy::copy 1024 -> 1024 -> 1024 bytes - in 1 hops
[I] StreamCopy.h : 158 - StreamCopy::copy 1024 -> 1024 -> 1024 bytes - in 1 hops
...

#include "AudioTools.h"
 
AudioInfo info(16000, 2, 16);
I2SStream i2s;
StreamCopy copier(i2s, i2s); // copies sound into i2s



void setup(void) {  
  // Open Serial 
  Serial.begin(115200);

  AudioLogger::instance().begin(Serial, AudioLogger::Info);

  // start I2S in
  Serial.println("starting I2S...");
  auto config = i2s.defaultConfig(RXTX_MODE);
  config.copyFrom(info); 

  config.pin_ws = 7;
  config.pin_bck = 8;
  config.pin_data = 43;
  config.pin_data_rx = 44;
  i2s.begin(config);

  Serial.println("I2S started...");
}

void loop() {
  copier.copy();
}

Steps I’ve Tried:

• Verified hardware connections to ensure the microphone and speaker are wired correctly.
• Tested different audio configurations (mono, stereo, 8-bit PCM, etc.).
• Increased logging level to AudioLogger::Warning for more detailed output.
• Simplified the setup to output a sine wave using SineWaveGenerator. This works perfectly, confirming that the output path is functional.

Questions:

• Should I use separate I2SStream instances for input and output instead of combining them into one?
• Are there any specific tweaks required for the ReSpeaker Lite to handle RXTX_MODE correctly?

Any suggestions or guidance would be greatly appreciated!

Thanks

[pschatzmann]

Try first to have the microphone working. properly.

It is my understanding that these are PDM microphones, so this will not work because you will need to have different definitions for reading and writing.

If I got it right, you can't use a different I2S port since the microphone and speakers share the same clock i2s pins.