With all due respect to Bill, I think the ability to detect "zero beat",
or to detect differences between two tones, has very little to do with
the acuity of one's hearing. It has to do with something else in the
brain.
I say this because I am extremely hard of hearing and have worn hearing
aids for the past 40 years. My ability to hear anything above about
4000 cycles is very limited. About ten years ago I took part in a
rather sophisticated aptitude testing regimen and part of the testing
had to do with something called "pitch discrimination". I took the test
twice, with hearing aids on and with them off, and scored 100% both
times. With my hearing aids off the tester had to crank up the volume
quite a bit so I could hear the higher pitched tones. Most of the tone
pairs were quite closely spaced, but I think my CW training (and
listening to weak signals on the low bands) may have made some
difference. It certainly wasn't because I have good ears!
-----Original Message-----
From: tentec-bounces@contesting.com
[mailto:tentec-bounces@contesting.com] On Behalf Of Bill Tippett
Sent: Monday, January 09, 2006 12:51 PM
To: tentec@contesting.com
Subject: [TenTec] [Orion] O2 versus Orion
N4PY wrote:
>I can get two tones easily less than one hertz apart by listening to
the
beats as long as the two tones are close in amplitude. What you
actually
hear is the phase between the two tones gradually changing, not the
frequency of the beat note. In this manner you can get much less than 1
hertz frequency difference. Try it. You will see what I mean.
Absolutely...and that's even with ~50 years
of headphone damage to my ears! :-) Unfortunately
my hearing also detects the 2+ Hz offset in Orion's
Main versus Sub frequencies when using Diversity
Mode (which is quite annoying at times).
Not everyone has good hearing and the ability
to detect beat frequencies. That's why planes have
visual synchronizaton meters so that pilots can adjust
throttles for identical engine RPMs and also why some
rigs have a zero beat light for those who can't hear
beat notes.
73, Bill W4ZV
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