[Vintage-Audio] Re Frequency Behavior

[Duane Fischer, W8DBF]

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 <sdaitch@ibb.gov>
To: vintage-audio@mailman.qth.net
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
>
> _______________________________________________
> Home: http://mailman.qth.net/mailman/listinfo/vintage-audio
> List Administrator: Duane Fischer, W8DBF
> ** For Assistance: dfischer@usol.com **

_______________________________________________
Home: http://mailman.qth.net/mailman/listinfo/vintage-audio
List Administrator: Duane Fischer, W8DBF
** For Assistance: dfischer@usol.com **