Ray, you are way way way off buddy but I see how you arrived at your
conclusion. Not a bad guess.
The hissing is coil noise. Let me expand on that for folks not familiar.
Coil noise is a generic electronics term for the sounds that circuits can make
from electrical resonance. When an electric
By now, I’m quite sure all y’all have heard of the latest with the iPhone7+.
It hisses at you when you push the unit very hard: that is, according to some.
After considering the matter, I have come to the conclusion that I think I
know what is or may be going on. I tried this with my iPhone6
