Clicking on silence

[Tuxorials]

So ive noticed that when i pause the music or theres a point in the music where the loudless goes to zero, the speakers do a slight click. it degrades the audio quality, especially at low volumes (i have 2kW of speakers connected to the dac so its almost always low volume)

Im using a ESP32 dev board, and a PCM5102A board

#include "AudioTools.h"
#include "BluetoothA2DPSink.h"

AudioInfo info(44100, 2, 16);
I2SStream i2s;
BluetoothA2DPSink a2dp_sink(i2s);
SineWaveGenerator<int16_t> sine(100);                // subclass of SoundGenerator with max amplitude of 32000
GeneratedSoundStream<int16_t> sound(sine);             // Stream generated from sine wave
StreamCopy copier(i2s, sound); 

static float notes_array_connected[] = { // frequencies aleatoric C-scale
    N_C3, N_E3, N_G3, N_C4
};
static float notes_array_disconnected[] = { // frequencies aleatoric C-scale
    N_C4, N_G3, N_E3, N_C3
};
void connection_state_changed(esp_a2d_connection_state_t state, void *ptr){
  Serial.println(a2dp_sink.to_str(state));
  if(state == ESP_A2D_CONNECTION_STATE_CONNECTED){
    play(notes_array_connected);
  }else if (state == ESP_A2D_CONNECTION_STATE_DISCONNECTED){
    play(notes_array_disconnected);
  }
}
void play(float notes_array[]) {
  static float freq;
  for (int i = 0; i < sizeof(notes_array); i++){
    freq = notes_array[i];
    sine.setFrequency(freq);
    unsigned long when = millis()+200;
    while (millis() < when){
      copier.copy();
    }
    sine.setFrequency(0);
    when = millis()+50;
    while (millis() < when){
      copier.copy();
    }
  }
}
void setup() {
  Serial.begin(115200);
  pinMode(27,INPUT);
  pinMode(21,OUTPUT);
  auto cfg = i2s.defaultConfig();
  cfg.copyFrom(info);
  cfg.pin_bck = 4;
  cfg.pin_ws = 15;
  cfg.pin_data = 2;
  i2s.begin(cfg);
  sine.begin(info,1);
  sine.setFrequency(0);

  a2dp_sink.set_channels (I2S_CHANNEL_STEREO);
  a2dp_sink.set_on_connection_state_changed(connection_state_changed);
  a2dp_sink.set_auto_reconnect(true, 1000);

  a2dp_sink.start("testing");
}
int dinky = 0;

void loop() {
  delay(10);
  float readings = analogReadMilliVolts(27);
  delay(10);
  readings+=analogReadMilliVolts(27);
  delay(10);
  readings+=analogReadMilliVolts(27);
  delay(10);
  readings+=analogReadMilliVolts(27);
  delay(10);
  readings+=analogReadMilliVolts(27);
  readings/=5;
  float reading= (readings * 5.6)/1000;
  if(reading < 9.6){
    digitalWrite(21,HIGH);
  }else{
    digitalWrite(21,LOW);
  }
  if (dinky % 20 == 0){
    dinky = 0;
  }
  dinky += 1;
  /*Serial.print(reading);
  Serial.println(",15,10");*/

}

any ideas or help appreciated on how to get rid of this (my first thought would be to always send some sound (really high frequency sine wave outside of audible range, just to keep the transmission between the esp and the pcm5102a dac active, but thats a dirty fix)

[harryberlin]

Do you have tried BluetoothA2DPSinkQueued instead of BluetoothA2DPSink?

[Tuxorials]

I tried now and it makes the problem better, but since i uploaded the sketch ive had a few exceptions. i forgot to save the first one but i have the second one. if i get a different exception i will upload it here

Debug exception reason: Stack canary watchpoint triggered (BtI2STask) 
Core  1 register dump:
PC      : 0x40098673  PS      : 0x00060c36  A0      : 0x80084f0e  A1      : 0x3fff2770  
A2      : 0x3ffbf388  A3      : 0xb33fffff  A4      : 0x0000cdcd  A5      : 0x00060c23  
A6      : 0x00060c20  A7      : 0x0000abab  A8      : 0xb33fffff  A9      : 0xffffffff  
A10     : 0x3fff2fe0  A11     : 0x3ffb6884  A12     : 0x3ffb6af8  A13     : 0x00000036  
A14     : 0x007bf388  A15     : 0x003fffff  SAR     : 0x00000004  EXCCAUSE: 0x00000001  
EXCVADDR: 0x00000000  LBEG    : 0x400926e1  LEND    : 0x400926f1  LCOUNT  : 0xfffffffd  


Backtrace: 0x40098670:0x3fff2770 0x40084f0b:0x3fff27b0 0x40084f46:0x3fff27d0 0x400850bd:0x3fff2800 0x400e6a3d:0x3fff2820 0x400e5d13:0x3fff2840 0x400e5989:0x3fff2860 0x40091805:0x3fff2880 0x40090a5a:0x3fff28a0 0x40090ae4:0x3fff28c0 0x400910f5:0x3fff28f0 0x401b8a2f:0x3fff2920 0x401b0583:0x3fff2940 0x401b0701:0x3fff2c50 0x401c5559:0x3fff2c80 0x401664ae:0x3fff2cb0 0x4016654b:0x3fff2ce0 0x400da75e:0x3fff2d60 0x400d3431:0x3fff2da0 0x400d34e9:0x3fff2e10 0x401be6da:0x3fff2e30 0x401be7b5:0x3fff2e50 0x400d6721:0x3fff2e70 0x400d662e:0x3fff2e90 0x400d681e:0x3fff2eb0 0x400d65f9:0x3fff2ee0

my sketch:

#include "BluetoothA2DPSinkQueued.h"

AudioInfo info(44100, 2, 16);
I2SStream i2s;
BluetoothA2DPSinkQueued a2dp_sink(i2s);
SineWaveGenerator<int16_t> sine(100);                // subclass of SoundGenerator with max amplitude of 32000
GeneratedSoundStream<int16_t> sound(sine);             // Stream generated from sine wave
StreamCopy copier(i2s, sound); 

static float notes_array_connected[] = { // frequencies aleatoric C-scale
    N_C3, N_E3, N_G3, N_C4
};
static float notes_array_disconnected[] = { // frequencies aleatoric C-scale
    N_C4, N_G3, N_E3, N_C3
};
void connection_state_changed(esp_a2d_connection_state_t state, void *ptr){
  Serial.println(a2dp_sink.to_str(state));
  if(state == ESP_A2D_CONNECTION_STATE_CONNECTED){
    play(notes_array_connected);
  }else if (state == ESP_A2D_CONNECTION_STATE_DISCONNECTED){
    //play(notes_array_disconnected);
  }
}
void play(float notes_array[]) {
  static float freq;
  for (int i = 0; i < sizeof(notes_array); i++){
    freq = notes_array[i];
    sine.setFrequency(freq);
    unsigned long when = millis()+200;
    while (millis() < when){
      copier.copy();
    }
    sine.setFrequency(0);
    when = millis()+50;
    while (millis() < when){
      copier.copy();
    }
  }
}
void setup() {
  Serial.begin(115200);
  pinMode(27,INPUT);
  pinMode(21,OUTPUT);
  auto cfg = i2s.defaultConfig();
  cfg.copyFrom(info);
  cfg.pin_bck = 4;
  cfg.pin_ws = 15;
  cfg.pin_data = 2;
  i2s.begin(cfg);
  sine.begin(info,1);
  sine.setFrequency(0);

  a2dp_sink.set_channels (I2S_CHANNEL_STEREO);
  a2dp_sink.set_on_connection_state_changed(connection_state_changed);
  a2dp_sink.set_auto_reconnect(true, 1000);

  a2dp_sink.start("test");
}
int dinky = 0;

void loop() {
  delay(10);
  float readings = analogReadMilliVolts(27);
  delay(10);
  readings+=analogReadMilliVolts(27);
  delay(10);
  readings+=analogReadMilliVolts(27);
  delay(10);
  readings+=analogReadMilliVolts(27);
  delay(10);
  readings+=analogReadMilliVolts(27);
  readings/=5;
  float reading= (readings * 5.6)/1000;
  if(reading < 9.6){
    digitalWrite(21,HIGH);
  }else{
    digitalWrite(21,LOW);
  }
  if (dinky % 20 == 0){
    dinky = 0;
  }
  dinky += 1;

}```

[mitchjs]

just looking at code; i dont like this line: for (int i = 0; i < sizeof(notes_array); i++){
prob shouldnt use sizeof on a passed in array, and doesnt sizeof return bytes?

size = sizeof(array_name) / sizeof(array_name[0]);
but not on passed in, as if i remember i pure c its calculated at compile time
best pass in the size to the function

[pschatzmann]

Apart from the errors mentioned above I would have the following suggestions

• Check your hardware settings: E.g that soft mute control is switched off
• Make sure that I2S can only be used by one functionality: eg. before doing your writing to I2S assign a NullOutput to A2DP and after you are done assign I2S again
• Take the error messages more serious: e.g. if you have a Stack canary watchpoint you should try to increas the Stack and analzse your backtrace to fiugre out where the issue might come from