[Vintage-Audio] Re Frequency Behavior

Tue Jan 13 18:01:05 2004

Ok, I'll dance with you one more time.
I wasn't having fun. I thought you were asking about the speed of sound
at various tones and I told you. The speed of sound is not dependent on
the frequency of the sound wave. Given the same starting point of the
sound, the same amplitude, the same medium, and the same temperature, a
100 Hz tone, 1000 Hz tone, or 5000 Hz tone will all travel the same
speed. Given that they travel the same distance, they all should hit the
receiver at the same time. Obviously, the farther they travel, all tones
will be proportionally weaker by the time they get to the receiver. How
the receiver interprets these sounds, the receiver limitations, etc.
would determine ultimately whether all tones would be heard. If you guys
believe that  some frequencies, traveling the same distance, through the
same medium, the same temperature, etc. are attenuated (high or low), I
want to see the math for that

Since you want to throw some credentials around, I  have a Master's in
EE, major in physics, and minors in business and math. (chuckle, chuckle
to you too)

Pete, WA2CWA

On Tue, 13 Jan 2004 12:07:24 -0500 "Duane Fischer, W8DBF"
<[email protected]> writes:
> 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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