Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: [Phys-l] Harmonics vs Overtones



Regarding BC's comment:

15.734 kHz; Women usually hear higher and longer.

bc, > 60 dB down at 3 kHz.


On 2009, Apr 02, , at 16:27, John Clement wrote:

I suspect
that most people on this list can no longer hear the 15kHz whistle
that analog TVs put out. The high end goes first.

Well, if we're going to be fussy about the analog color NTSC horiz.
line freq., it is supposed to really be
2250/143 kHz ~= 15.73426573...kHz. [And while we're at it, the
vertical field rate is supposed to be
60/1001 kHz ~= 0.059940055994...kHz, and the frame rate is supposed
to be 30/1001 Hz ~= 0.02997002997...kHz, and the color subcarrier
frequency is supposed to be 511875/143 kHz ~= 3579.5454545...kHz.]

But I haven't been able to hear a horizontal flyback transformer
vibrate since I was in my late 20s. My wife has said she could hear
it for nearly 2 decades longer than I could, but now she has finally
also aged to the point where she can't hear it either. My daughters
(in their 20's) say they can still hear it. Our family is way
behind the times in converting to DTV/HDTV, but we have analog cable
so we're not in a hurry.

David Bowman