I was at my co-op board meeting last night in a small elementary school auditorium - stage, high ceiling, a coupla columns, light fixtures hanging from ceiling. The speakers were not miked; they were just speaking a little bit louder than normal so the 50 or so people in the auditorium could hear.
Two people start getting this crazy feedback in their hearing aids - a high whistling sound that I could hear from 10 and 20 feet away, respectively. Not at the same time.
Then, after adjusting the hearing aid somehow, they both got it again a few minutes later. Again, not at the same time.
Can someone explain, in layperson’s terms, what causes this? What adjustment were they making? What adjustment should they have made to keep it from recurring?
Hearing aid feedback is primarily caused by a poor fit combined with a high incident sound volume level (e.g., a noisy room). The hearing aid should sit firmly in the ear canal. If it doesn’t, sound from the output can leak out and get picked up by the sensitive microphone. Once started, feedback can be squelched by both lowering the volume and re-adjusting the fit.
My father always blames a low battery when his start squealing for no reason. A fresh battery does seem to make a difference because I have stood there and watch him replace the battery to end the noise. Naturally it also causes him to readjust the fit at the same time… so maybe it has nothing to do with the battery.