Weird coil whine noise from iPhone Xs Max

[alpi123]

I accidentally discovered this and don't know if it's common or not.

If I hold on my phone's right bottom speaker (while the phone is on) to my ear, but very close, I can hear like a buzzing noise, or coil whine if you will.

Does anybody else have that?

 

[liljak]

Tested on my XS Max, I also hear it.
Was on the home screen with the mute switch enabled.