! The maximum volume of the PCM5102 causes audio distortion

[Toy-Jie]

Hello everyone,

I am using the ESP32 A2DP to output audio to speakers through the PCM5102, and I have enabled set_volume(127), with the volume being determined by the speaker device.

However, setting set_volume(127) results in severe distortion with crackling sounds, while set_volume(100) resolves this issue. But some Android devices do not support set_volume.

? Could anyone explain how the crackling sounds are generated?
? Is it possible to independently set the output volume of the PCM5102?

[pschatzmann]

I was never using this value since this is much too loud and I always used the volume control on the phone to set the right volume.
I committed a correction that clips the values if they overflow...

[Toy-Jie]

Thank you for your response. I installed version 1.8.6, but it did not resolve the issue. On the contrary, the sound quality has significantly deteriorated.

Reducing the volume from 127 to 100 results in a noticeable improvement.

static const i2s_config_t i2s_config = {
.mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_TX),
.sample_rate = 44100,
.bits_per_sample = (i2s_bits_per_sample_t)16,
.channel_format = I2S_CHANNEL_FMT_RIGHT_LEFT,
.communication_format = I2S_COMM_FORMAT_I2S_MSB,
.intr_alloc_flags = 0,
.dma_buf_count = 16,
.dma_buf_len = 256,
.use_apll = true,
.tx_desc_auto_clear = true
};

[pschatzmann]

Oh my god: stop using this obsolete ESP32 Arduino version!
The current release is 3.1.1.

You are several years behind....

[Toy-Jie]

Apologies for the miscommunication. I am currently using ESP32 2.0.11 and A2DP 1.8.6. I am in the process of switching to ESP32 Arduino 3.0.7 and will provide feedback shortly...

[Toy-Jie]

Hi, I am currently using ESP32 Arduino 3.0.7 and A2DP 1.8.6. The demo is bt_music_receiver_arduino_i2s_3.ino. However, I am still experiencing distortion at maximum volume, which is quite troubling. I look forward to your response...

[pschatzmann]

I was testing with an AudioKit and cranking up the volume on the phone to the max. This provides a clean sound!

If this is not working for you, then I would rather think that it is a hardware problem...
Maybe your PCM5102 does not get enough power...

[harryberlin]

i'm using 150Ohm Resistor between Audio Positiv and Audio Ground for each Channel.

[pschatzmann]

Did you test my correction ?

[harryberlin]

Did you test my correction ?

No, my experience with the pcm5102 device on raspberry is, the audio is clipping. decreasing volume does not really solve the problem. the 150 Ohm resistors did solve the clipping audio problem.
so i did the same with esp32.

[pschatzmann]

Actually I could reproduce your issue on an AudioKit: it was indeed a software issue as well!