I get all kinds of shit hurled in my direction.
I do hope that that comment was not about me. I made every attempt to discuss rationally and politely with you yesterday and the day before, while you were little but patronising and arrogant in return. I do not wish to reopen any hostilities, but I cannot turn a blind eye while you posture as a completely innocent victim. There are valid reasons why people get extremely frustrated with you and having the support of these good people here that you have helped does not erase that fact.
In order to preserve the peace could I therefore suggest that you not provoke the situation yourself any further.
You are mistaken. My moderate high frequency hearing loss is nothing compared to the dB level at the foot of Niagara Falls. That 90dB threshold you referred to earlier was at 12.5K, an ultra-high frequency that is way outside the range of the sounds encountered in everyday living! Putting it in more concrete terms, the frequency of the highest note on a piano is 4186 Hz. My 90dB threshold is at 12,500 Hz! And I always wear my hearing aids anyway. So if that's where you think you got, then you got nowhere.
Now, without any "sh**" intended, could we calmly and courteously make one further attempt to illuminate the topic of the thread a little. As I said yesterday, I am not claiming there is one answer to the question. As yesterday, I am exploring one possible mechanism at work. If this offends you then you are very welcome to take your own advice and stop reading my posts (as are any other readers). This is the point at which to do so if that is your wish (although of course your engagement and input is most welcome). The rest of my post is only an attempt to illuminate a technical question posed in the original post. Nothing more or less.
Here is my hypothesis:
If Dr. Nagler wears his hearing aids in the "Maid of the Mist" then I guess that they must be capable of not amplifying any sound to a point loud enough to cause hearing damage. According to the following webpage the noise level at the loudest point of Niagara Falls is 95dB:
http://teacher.scholastic.com/activities/explorations/bats/libraryarticle.asp?ItemID=235&SubjectID=141&categoryID=3
That is the loudest point, not necessarily the point reached on the "Maid of the Mist". But lets say 95dB reaches Dr. Nagler's outer ear/hearing aid. The hearing aid would presumably not amplify this at all.
I do not know Dr. Nagler's level of hearing loss at the sound frequencies of the waterfall. If it were around 45dB (for example), then Dr. Nagler would hear the waterfall as being around 50dB. So the situation we would have is a very high frequency (12.5kHz?) 11dB SL tinnitus failing to be masked by 50dB of lower frequency noise.
This scenario seems reasonable to me, and less of a mystery. Any input or modification of the hypothesis is welcome in a spirit of open discussion (including real figures to replace my hypothetical ones). I have to be away from the internet for a while, so cannot respond immediately.