You could hear the whine from across the room a few seconds before a call would ring through.
People always asked how I managed to answer the phone so fast. Electromagnetic Supplementary Perception, of course.
It was clearly electromagnetically "noisy", but I do't recall ever having heard any on my phones make any unexpected audio noise... (My old-and-abused rock concert and motorcycle weary ears probably can't get up as high as inverter whine any more though...)
Also, GSM phones used TDMA (keying the transmitter on and off to occupy one of -hm- eight, I believe - time slots on a given channel.)
This is practically asking for EMC issues.
LTE, on the other hand, transmits continously (I believe - I do not work in RF engineering anymore, but try to read up on new tech every now and then.:) - much less interference-causing than the constant on/off of TDMA.