I guess the minimum setting which is completely off wouldn't generate EM hum, but I don't wear hearing aids so I wouldn't be sure. These last two posts have been about hearing aids, not headphones by the way. They have a little 'T' setting which is explicitly designed to pick up the EM frequencies generated by a coil in the earpiece of telephone sets for example - I didn't think you were meant to use it in general use, but I guess once you've set it on it might be a bit of a faff turning it off again. As far as I've heard, the Pyra is supposed to use a higher frequency to illuminate its backlight. I'd guess this would result in a higher tone in your hearing aid, and if that's hypersonic to you then that would not be a problem.