Music player via ESP32

Question

I have a music player via an ESP32 and an SD card module

Structure:

SD card module (with the .wav files) -> ESP32

ESP32 pin 26 to Audio amplifier module LM386 IN (with 10µF capacitor between IN and GND) and ESP32 GND to Audio amplifier module LM386 GND and from Audio amplifier module LM386 GND and VCC to the external power supply constant 5V

From audio amplifier module GND and OUT to the loudspeaker (8 Ohm 100W)

Problem:

When I want to play the .wav files from the SD card via the ESP32, I always get a loud noise when it plays and only the music of the .wav file in the background

Can anyone help me?

Code (is just the code snippet):

bool startAudioPlayback(const String& pfad) {
  // Vorhandene Instanzen löschen, um Speicherlecks zu vermeiden
  if (wav != nullptr) {
    wav->stop();
    delete wav;
    wav = nullptr;
  }
  if (file != nullptr) {
    delete file;
    file = nullptr;
  }
  if (out != nullptr) {
    delete out;
    out = nullptr;
  }

  // Neue Instanzen erstellen
  out = new AudioOutputI2S();
  out->SetPinout(27, 26, 26);  // Anpassen der Pins je nach ESP32 Setup
  out->SetGain(0.1);           // Setzt die Lautstärke auf 10%
  out->SetRate(480000);         // Common sample rates are 44100 or 48000 Hz
  out->SetBitsPerSample(16);   // Use 16 for CD quality audio
  out->SetChannels(2);         // Set to 2 for stereo

  file = new AudioFileSourceSD(pfad.c_str());  // Dateipfad als C-String übergeben
  if (!file->isOpen()) {
    Serial.println("Fehler: Datei konnte nicht geöffnet werden");
    delete file;
    file = nullptr;
    delete out;
    out = nullptr;
    return false;
  }

  wav = new AudioGeneratorWAV();
  bool success = wav->begin(file, out);

  if (success) {
    Serial.println("Spiele Audio ab...");
    while (wav->isRunning()) {
      if (!wav->loop()) {
        wav->stop();
      }
      delay(1);  // Kürzere Verzögerung, um die Schleife effizienter zu machen
    }
    Serial.println("Audiowiedergabe abgeschlossen.");
  } else {
    Serial.println("Fehler beim Starten der Audiowiedergabe");
  }

  // Instanzen löschen
  delete wav;
  delete file;
  delete out;

  // Instanzen auf NULL setzen, um wiederholte Zugriffe zu verhindern
  wav = nullptr;
  file = nullptr;
  out = nullptr;

  return success;
}

Answer 1

You can't put a 10uF capacitor from DAC output to GND. Or from any IO pin for that matter. It will prevent the audio from working and may even damage MCU output. Remove it.

Maybe you intended to connect the cap in series to remove DC. So connect it accordingly.

Also the component values are unknown. At least don't mount the bass boost components until you get it working. And make sure the Zobel network is present for providing high frequency load impedance so the amp does not oscillate.

There is also no supply bypass cap on the supply inpu pin or on the bypass filter pin.

If you draw the circuit and components as per the data sheet examples, it should work.

Edit: Also, your schematics are not correct because you say you use a LM386 module bought from Amazon. It also has realy

And you are outputing the WAV file as digital audio stream on I2S bus, you have no DAC to convert it to analog and you connected the digital output which is just series of bits into the analog amplifier.

Which is why it sounds the way it does - you can hear the audio being distorted but recognizable, because I2S data output is not analog audio, it's digital bits.