Regular click on audio playing but ONLY with basic speakers, no problem with regular headphones

[samyrabih]

Hi!
I'm currently finishing a Teensy-based audio guestbook and I'm trying to use the headphones output to play an intro before recording.
I'm using:
- Teensy 4.0
- Audioshield

With a regular headphones plugged on the audio shield, the WAV present on the SD card is played without problem.

But if I use small speakers (like the ones used for Arduino based systems, 3W/4 Ohms, two speakers in parallel), I can hear a regular click in background.

I was able to record it using my smartphone.

The frequency of this click is ~4.58hz

The code can be found here: https://github.com/samy/une-histoire-au-bout-du-fil/blob/main/Livre_dor/Livre_dor.ino#L355

The speakers are directly plugged on the jack of the audio shield.

If you have any idea, it should be cool

 

[samyrabih]

Since it is a old phone-based system, I put back the old speaks of the phone (instead of modern ones) and it seems to fix the problem.

Perhaps kind of resistance/impedance problem ?

So I will keep the old ones.

Thanks for reading me