[Fred.]

On Aug 15, 7:18*pm, bob wrote:
On Aug 15, 1:21*pm, "Fred." wrote:

I'm sure that a large number of differences in sound people claim they
can hear are based on ego and/or bias as you suggest. *But, I'm
eaually sure the human ear is remarkable in its capabilites, and in
the differences in capabilities between people. *We have only the
roughest idea what the typical human ear is sensitive to, let alone
the range of the atypical.

Human hearing has been a subject of scientific study for a good
century and a half. We have quite a good idea of what the human ear is
sensitive to. Some audiophiles may not have a good idea of what the
human ear is sensitive to, but that's a reflection on them, not on the
state of scientific knowledge.

While tend to reserve judgement, I'm truly reluctant to reject any one
claim on nothing more than what I personally hear, or on an electrical
measurement, which itself is based on certain expectations concerning
*normal* human hearing.

Claims are easy to reject when they fall well out of the range of even
"exceptional" hearing. There's a gray area, of course, where only
careful listening tests can tell you whether something is or is not
audible to a particular person. None of the claims in this thread come
anywhere near that gray area.

bob

Bob,

While I don't claim a great ear, I do know that when I was younger I
used to experience discomfort in stores which left their ultrasonic
motion detectors on during the day. Since this was obviously
impossible, you can imagine that I didn't talk about it much.
However, I did mention it once to my wife, who is a speech
pathologist, snd has some knowledge of hearing science. She, like you
would, discounted it as a minor insanity. Later our daughter
complained of the same problem. Since I never talked about it with
our daughter, I guess it's hereditary insanity :-).

Later, we encountered a vision specialist who had found that a number
of pupils who had been thought to be dislexic, really weren't having
processing problems, but had very high contrast sensitiviy. He had
ordered some lenses with 97% tint for one pupil. He had to try
several manufacturers because most of them "knew" nobody could see
through such lenses. During his presentation he passed a pair of the
lenses around the audience. As expected, most of us, including me,
with contrast sensitivity mesuring in the 99th percentile, couldn't
see much, but one woman, looking a printed page though them,
exclaimed, "Wow, that's great", and proceeded to read off the page
with obvious pleasure.

I also recall, working in R&D, discovering a serious defect in an
outsourced power supply, where the symptom which made us look at it
was a flicker in the lights which only one person could perceive, and
they weren't even quite sure they were seeing it.

Science produces theorectical models which are useful for prediction.
You can apply those models to "easily" discount claims, and have a
very high probability of being right. Yet, that leaves a finite
probablity of being wrong. And, any competant physicist will tell you
that science confines itself to measuring things that are relatively
easy to measure.

Our use of language to describe our perceptions, combined with social
accomodation, like my not talking about my sensitivity to ultrasonics,
tends to blind us to the very large differences in what people
perceive. And, dealing with things on a statistical basis, tends to
blind us to the existence of extremes.

Many claims should be met with doubt, and "show me". I'm just
suggesting that if you're too sure about what you "know", and take the
easy path of outright regjection, you may miss something important,
and incidentally commit an injustice.

Fred.