RTA
Peter Larsen wrote:
Scott Dorsey wrote:
Note that none of the standard tests go above 8 KC, because going
higher than that requires compensating for the differences in ear
structures between different people and it becomes more expensive.
Hmmm ... I always thought it was based on the religion of "important for
speech" discounting all other aural pleasure.
Nope, it's based on economics and the religion of diminishing returns.
But to be honest, speech perception is very important, and your insurance
company probably doesn't care about your other aural pleasure.
But if there is a severe enough problem, it'll show up below 8 KC too.
Interestingly the most likely place for early impulse noise damage is 6 kHz
and falls smack dab in the gap between spot checking at exactly 4000 Hz and
exactly 8000 Hz.
Yup. That's because so many things make sound in that range, so we are
exposed to a lot of it.
Anyway, it was a different rant I had on my mind, namely that one should not
confuse hearing threshold with frequency response of hearing and that one
needs to understand the concept of recruitment and the fact that signal at
neighboring lower frequencies add as a bias that facilitates audibility. It
is the latter effect that is the cause of people seemingly being able to
hear above what their threshold graph suggests that they are good at.
This is true, but this is a whole other set of hearing problems which require
different tests than the simple threshold test. A lot of hearing deficits,
and most minor ones, just result in a threshold shift. Others do result
in linearity changes. And yes, increased overall level can make it easier
to hear lower level sounds because of the effect you describe.
But it
is a nuisance to talk to the house staff during the intermission and hear
them saying "Ah, the bell is chiming, they (the audience) are coming back
in" .....
In the US, it's more common to dip the house lights for the five-minute
call. Maybe because we have more deaf audience members...
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
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