Strange noise when recording audio

[jjamjohnson]

Hello all,

When using Bluetooth or WiFi there is clicking noise in the recording. I have tried to install various capacitors on the modules between VCC and GND but no significant improvement was detected. When recording to SD CARD without wireless started, I do not see this kind of issues.

I am experiencing the same issue with following setups:
1. ESP32 DevKit board + max4466 microphone amplifier + electet microphone + USB powerbank
2. ESP32 DevKit board + max9814 microphone amplifier + electet microphone + USB powerbank
3. Wemos D32 + max4466 microphone amplifier + electet microphone + LiIon battery (1.5A max current)
4. Wemos D32 + ES8388 audio codec + electet microphone + LiIon battery (1.5A max current)
5. Wemos D32 + ES8388 audio codec + electet microphone + Samsung USB PowerBank

For the first three setups, I am using timer to sample built-in ADC and record audio. For 4th and 5th I am using samples provided by ESP-ADF (examples/recorder/pipeline_raw_http and examples/recorder/pipeline_recording_to_sdcard).

The interesting thing is when using LyraT 4.3 board there is no this kind of issue with original microphones. The issue reproduces when I solder my microphone on the LyraT board or use microphone from LyraT microphone on my setups (4 or 5). This tells me that the circuit placed on microphone input needs to be adjusted to specific electet microphone, probably its impedance but not sure how. I am using microphones that are provided with max4466 modules.

Can anyone please help me with this?

Kind regards