[Trevor]

On 25/04/2017 5:29 AM, Michael Black wrote:
On Tue, 25 Apr 2017, geoff wrote:
On 24/04/2017 7:45 PM, Trevor wrote:
Secondly if we are to take your statement literally then nobody
should wear ANY hearing aid for fear of damaging what is left of
their hearing at any frequency!

I'm surprised people bother to make these comments without
knowing anything about hearing aids.

And despite me making no claim to know anything about audiology ,
it would still vastly surprise me that the simple remedy for a loss
at a particular band is solely to boost the **** out of that band.
14k, 8k, 3k, or whatever.

What I remember is that the ear has two or maybe more levels of
nerves to detect sound, because otherwise the ear would be required
to handle too wide a dynamic range. I'm not sure how that translates
to loss at higher frequencies, but from what I was told, one could
lose the ability to hear low level sounds, but still hear loud sounds
fine. This was decades ago, and maybe it was a simplification for
"the layman".

I don't think you can boost the high frequencies by too much, and
expect "perfect" hearing. One has to live with something in between
"original" and bad hearing.

For many people the ability to hear above a certain frequency is lost
completely, or close to it, and no amount of gain would help. But
hearing aids are designed to cover the voice frequency range, and rarely
go past 8kHz anyway. Fairly high boost in the 2-8kHz range is not that
uncommon for those with simple high frequency loss. But *NO* hearing aid
will give a user "perfect hearing", only something more useful perhaps.



Someone mentioned their parents or grandparents getting used to
hearing aids, and giving up. Apparently that's common, one adjusts to
what there is, so hearing aids can take time to adjust to. So I
assume people adjust to the level of improvement that a hearing aid
can offer.

The electronics don't or didn't provide the same level of dynamic
range as regular ears, so AGC, automatic gain control, kicks in
somewhere in hearing aids, so that's another thing one has to adjust
to.


Actually the aids themselves can easily cover the ears dynamic range at
very low gain, however if you have say 60db loss, maintaining 100dB
dynamic range would require a peak SPL of over 160dB! Not something
anybody could tolerate even IF the aids could manage something remotely
close to that. Fact is very loud sounds still sound loud to most hearing
aid users so the dynamic range provided must be restricted if they are
to hear quieter sounds at all.