[Vintage-Audio] Re Frequency Behavior

Tue Jan 13 12:11:01 2004

Sheldon, 	

Yes, on all points. 	

Pete was having some fun throwing math equations around, but Pete, I have a
minor in mathematics from the University of Michigan, so be careful! You might
have to buy some new batteries for your calculator OM! (chuckle)		

Because I am blind, I know far more about what people hear, listen to, filter
out and so forth than anyone who is sighted. I use it every single day. A
sighted person learns 92% of everything visually. That means all of the other
senses, and there are far more than the five people think of, only 8% get used.
What is the greatest sense organ anyhow? The skin! What do we do? We cover most
of it up so its functionality is severely limited. Before we go down the path of
nudists ... Ha Ha.  	

Bob? If you want to debate hearing, write me off list. Who was it that said:
"Everybody is talking, but nobody is saying anything?" 	

DBF	

----------
From: Sheldon Daitch <[email protected]>
To: [email protected]
Subject: Re: [Vintage-Audio] Re Frequency Behavior
Date: Tuesday, January 13, 2004 8:39 AM

Duane,

I think we may be in total agreement.  Maybe I wasn't quite as elegant in
writing.  The only part where I might disagree, in regards to radio
reception, is under the situation where next channel interference is
high enough, and the receiver has variable bandwidth filtering, so
that the higher audio frequencies are filtered out.  Depending on the
depth and shape of the filters, one could strip out most of the higher
audio frequencies, of a high pitched female announcer, and yet
still pass the lower frequencies of a heavy-bass announcer.  Under
this unique set of circumstances, you could make a case for
the lower audio frequencies.

Pete has a nice explanation of the speed of sound, but I think what he
overlooked is the attenuation factor of higher audio frequencies
vs lower audio frequencies.  I believe that was part of your concern,
wasn't it, range, not velocity.

Sheldon

"Duane Fischer, W8DBF" wrote:

> Sheldon,
>
> First, the human ear is trained from before an infant is born to listen in a
> specific frequency range for vocal patterns. Hence, humans focus on certain
> frequency ranges and filter out others without even realizing they are doing
so.
> A higher pitched voice tends to be heard above the general din of noise
> pollution we all experience in our daily comings and goings.
>
> The best example of this filtering I can think of, is that of a mother hearing
> her child several rooms away with a TV set going, people talking and all sorts
> of other racket. She hears the child whimpering and nobody else in the room
> hears a thing.
>
> The low note carries the greater distance because it has a longer wavelength.
> For instance, the kid down the street with the kickers in his trunk. You can
> hear the bass a quarter mile away, but nothing else.
>
> It was said that a female announcer on a radio station could be heard at a
> greater distance because of her high pitched voice. I disagreed. The radio
> signal carries only so far, regardless of what sex is doing the talking.
> However, because her voice is generally of a higher pitch it may be easier to
> hear because it is above the area of the general noise. So it 'appears that
she
> is heard farther away simply because the frequency of her voice is higher than
> the background noise.
>
> Your thoughts?
>
> DBF
>
> ----------
> From: Sheldon Daitch <[email protected]>
> To: [email protected]
> Subject: Re: [Vintage-Audio] Re Frequency Behavior
> Date: Monday, January 12, 2004 3:42 PM
>
> Duane,
>
> Maybe we are trying to compare apples and oranges here.
>
> In general, lower audio frequencies are attenuated less than
> higher frequencies, thus, you can hear the rumble of the loud
> bass much further away than the higher frequencies from the
> same boom box.
>
> When you get into the second part of your question, which
> announcer would be "heard" at a greater distance, assuming
> no interference, one would think there should be no
> difference in radio range, if that is the intent of your question.
>
> Now let's subject the signals to some interference, and
> then it becomes a little more difficult to answer, as the filtering
> necessary to reduce or eliminate the interference  might also
> be the same frequency range as the announcers voice.
>
> So now, at the RF side of the equation, I am at a loss for
> a definitive answer, as I think it might be a lot more
> subjective and related to the skills of the listener.
>
> More thoughts?
>
> Sheldon
>
> "Duane Fischer, W8DBF" wrote:
>
> >
> > Is it true that a higher note is often easier to hear, but a lower note
> travels
> > a greater distance?
> >
> > Now leaving the length of the sound wave out of the discussion momentarily,
> > given a male and a female announcer for a radio station, speaking at the
same
> > volume into the same mike, which signal will be heard at the greatest
> distance?
> > The one with the highest voice pitch or the one with the longest wave
length?
> >
> > Duane W8DBF
> >
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