On Fri, 13 Apr 2007 05:36:03 -0700, Frank Gilliland
wrote:

+++On Fri, 13 Apr 2007 03:09:54 GMT, james wrote
+++in :
+++
+++snip
+++I stated how could one detect it without a scope? please reread my
+++post and comprehend better.
+++
+++
+++I reread the original post as well. It's pretty obvious, even to the
+++most casual observer, that you meant to say "subsonic".
+++
+++
+++100 Hz is hearable or percieved. As I stated before there is a subtle
+++difference bwetween audible and hearable. Yes you can "hear" 100Hz if
+++increase the signal power compared to a 1000Hz tone. But at equal
+++power desity, a 100 Hz tone by most people is not "hearable" or
+++audible.
+++
+++
+++I didn't see anything in his post about the loudness of this 100 Hz
+++noise. Whether it was "hearable" or "audible", it was detected
+++nonetheless. And apparently it was loud enough to cause a problem, so
+++it's safe to assume that this "noise" (his word) was detected without
+++a scope. Your damage-control explanation about subtle differences in
+++definitions just doesn't resonate.
+++
+++
***********

That maybe true in your perception. Still my first statement is not
all that wrong. With communication receivers that I deal with have
high pass filters centered near 300Hz along with low pass filters to
filter above about 3000Hz. So if a 100Hz signal is causing
interference, it should not be heard if it is passing through the
audio block. I did forget that there is means for a low
frequency(below 300Hz) signals can bypass the audio block and get to a
speaker. Even still the quality of speakers in low tier CB radios
probably do not have that great of a frequency response. Then also a
harmonic of the 100Hz signal if large enough could pass through the
audio block.

LIke I said I never intended to get off on a tangent on audible or
hearable signal levels and human hearing response. I still thought
that I was in part correct with my first statement that a 100Hz signal
is at the low end of "hearable" and is best detected with a scope.
What I did forget is that the third harmonic and greater would be very
audible. I findeed that were the case.

If I am at fault of anything it is not taking enough to to be more
explicit and to general in my comments.

james