I would say, based on what I hear and not that I have any kind of doctor or auduologist background, that certain frequencies could overlap a bit where the aid is producing very loud frequencies in a range where your hearing may be well or almost perfect resulting in those frequencies being too loud.
As for what is too loud, I think, over time, any exposure to loud noise builds up and deadens whatever it is that causes loss of hearing.
I know I must be careful with my aids in if I am crumpling paper or even urininating into water in an enclosed space can almost hurt. In one of my bathrooms, I have made an antique bathroom out off it on my first floor and there are three walls and a window (in one of the three walls) that are fairly close to the toilet. With my aids in, if I hit the water, it almost hurts my ears. I find it best to aim where their is no water. Clanking dishes and silverware, like when you load and unload a dishwasher can also be in that frequency!
If you see my audiogram, there is a sudden drop. I suppose if we were to analyze that drop and break the sudden loss down even finer, we may find that it drops at a bit different location than the aids are set for. The problem is, how many of these different changes in hearing can be fine-tuned then fine-tuned into the aid? I don't even know if my aids would have the flexability to be adjusted, say, nine times for such areas of rapid decline or even of rapid gain (if the is the proper word for when the ears pick up the hearing again).
250 500 750..1k..1.5k..2k..3k..4k..5k..6k
SRT=15 15; Audiometry 92% 80%
10/22/10 - First HA's, excellent results with (L&R) Oticon Hit Pro (BTE), RITE with Standard Speakers & 10mm Open Domes