Hmmm, ever see bear s**t in the woods?

You obviously haven't been watching the current
Charmin commercials...

I'm talking real world.

You mean those cute little pastel bruins aren't REAL? I'm heart-broken...

While you can choose to position source and receiver at any distance
apart, unless a receiver exists, no Doppler effect can be perceived.

This is both incorrect and meaningless.

Meaningless, because you can't see anything without an eye or camera, hear
anything without an ear or microphone.

Incorrect, because the Doppler effect occurs when the source or listener moves
with respect to the medium. Period.

"William Sommerwerck" wrote in message

Hmmm, ever see bear s**t in the woods?

You obviously haven't been watching the current
Charmin commercials...

I'm talking real world.

You mean those cute little pastel bruins aren't REAL? I'm
heart-broken...

I thought you spent time in the woods, Bill.

"William Sommerwerck" wrote in message


Incorrect, because the Doppler effect occurs when the source or
listener moves with respect to the medium. Period.

This is an odd kind of sort of true statement. The basic cause of Doppler is
relative motion between the source and the receiver. However, for that to
happen, one or both have to be moving with respect to the medium. That is
unless there is some kind of wind shear. I guess wind shear is the
falsifying condition. It's not always true.

"William Sommerwerck" wrote in message

The distortion does not exist until the sound reaches the receiver.

WRONG!

The Doppler shift occurs AT THE SOURCE.

I'll go so far as to say that it is preconditioned at the source.

If I am moving at the same
velocity as the source, there is a second Doppler shift that cancels
out the first.

That's one way of looking at it.

Doppler shift is produced by motion relative to the medium -- not by
relative motion between the source and the receiver.

I falsified that in another post. Two words: wind shear.

THINK... think, think, think... before you lift finger to respond.

Good advice, and now its time for you to take it! ;-)

"Natalie Drest" wrote in message



I bet you think my name really is Natalie Drest.

You're lying? Whoda guessed?

I should introduce
you to my friend Sarah Bellum, she writes all my stuff...

Is she like Bob's Auntie Bellum?

In this place, William Sommerwerck was recorded saying ...
The distortion does not exist until the sound reaches the receiver.

WRONG!

The Doppler shift occurs AT THE SOURCE. If I am moving at the same velocity as
the source, there is a second Doppler shift that cancels out the first.

Doppler shift is produced by motion relative to the medium -- not by relative
motion between the source and the receiver.

THINK... think, think, think... before you lift finger to respond.

OK _ I've thunked and thunked and thunked and this argument still seems
pretty perverse to me.

What you're saying is that if I'm riding on the traditional train,
listening to its whistle I will experience a Doppler effect that is
equal and opposite to that experienced by the whistle - and that's why I
won't hear any change in the tone of the whistle!

I think not.

--

George
Newcastle, England

Problems worthy of attack
Prove their worth, by hitting back [Piet Hein]

Incorrect, because the Doppler effect occurs when the source or
listener moves with respect to the medium. Period.

This is an odd kind of sort of true statement. The basic cause of Doppler is
relative motion between the source and the receiver. However, for that to
happen, one or both have to be moving with respect to the medium. That is
unless there is some kind of wind shear. I guess wind shear is the
falsifying condition. It's not always true.

I should clarify this by saying that the Doppler effect (the squashing or
stretching of wavelengths) exists whether or not there is someone or something
to perceive it. Whether it is perceived depends on whether the "perceptor" is
moving.

Note that if the tran is still and I move at 70 mph wrt the train, I hear a
Doppler shift.

What you're saying is that if I'm riding on the traditional train,
listening to its whistle I will experience a Doppler effect that is
equal and opposite to that experienced by the whistle - and that's
why I won't hear any change in the tone of the whistle!

That is absolutely correct.

Think about it.

Hmmm, ever see bear s**t in the woods?

You obviously haven't been watching the current
Charmin commercials...

I'm talking real world.

You mean those cute little pastel bruins aren't REAL?
I'm heart-broken...

I thought you spent time in the woods, Bill.

Well, I do occasionally attend rondys... There's one coming up Labor Day
weekend...

I'm not afraid of bears, but if I saw one coming my way, I think common sense
would override my lack of fear.

In article ,
William Sommerwerck wrote:
What you're saying is that if I'm riding on the traditional train,
listening to its whistle I will experience a Doppler effect that is
equal and opposite to that experienced by the whistle - and that's
why I won't hear any change in the tone of the whistle!

That is absolutely correct.

Right! And if you play a 20 Hz and a 2 KHz tone through a full-range
speaker, the cone will move with both signals and the higher frequency
signal will be modulated in frequency by the 20 Hz signal. BUT, if you
mount your head on a driver producing a 20 Hz signal (which does not
even need to be in phase with the first 20 Hz signal), both the 20 Hz
note AND the modulation will be inaudible at your position.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

In this place, William Sommerwerck was recorded saying ...
Incorrect, because the Doppler effect occurs when the source or
listener moves with respect to the medium. Period.

This is an odd kind of sort of true statement. The basic cause of Doppler is
relative motion between the source and the receiver. However, for that to
happen, one or both have to be moving with respect to the medium. That is
unless there is some kind of wind shear. I guess wind shear is the
falsifying condition. It's not always true.

I should clarify this by saying that the Doppler effect (the squashing or
stretching of wavelengths) exists whether or not there is someone or something
to perceive it. Whether it is perceived depends on whether the "perceptor" is
moving.

Note that if the tran is still and I move at 70 mph wrt the train, I hear a
Doppler shift.

Maybe we're talking at cross purposes here but isn't that just another
way of saying there has to be relative motion between source and
receiver? Either or both can move but their motion relative to one
another is what is important.

--

George
Newcastle, England

Problems worthy of attack
Prove their worth, by hitting back [Piet Hein]

George Perfect wrote:

The distortion does not exist until the sound reaches the receiver.

Arny! That's about the silliest thing I've ever heard from
someone that is techno-savvy.

Maybe he didn't express himself absolutely accurately but Arny still
makes an important point - and one that I still suspect you may be
missing.

The Doppler effect requires source and receiver to be spatially separate
and in relative motion. If another body was (say) between source and
receiver but travelling in step with the source, it would not perceive
any Doppler effect.

It is therefore true to say that Doppler occurs only at the receiver.

Shouldn't it be possible to accurately describe, without regard to
the receiver, the DIFFERENCE between two waveforms - one with Doppler,
and one without?

--
Steve Maki

Bob Cain wrote:


It is possible to talk about it relative to anything including the
air with no receiver present. It's evidence is in the wavelength of
the tone in the air if you know the frequency in the reference frame
of the transmitter.


If you know, then you are the receiver. Without a receiver you can't
know anything. The transmitter knows nothing of the shift.

Maybe we're talking at cross purposes here but isn't that just
another way of saying there has to be relative motion between source and
receiver? Either or both can move but their motion relative to one
another is what is important.

Not quite.

Relative motion between source and observer is NOT required for there to be
Doppler shift. Doppler shift occurs WHENEVER the source is moving.

It is whether the listener is in motion with respect to the source that
determines whether he will hear the Doppler shift.

"Scott Dorsey" wrote in message
...
In article ,
William Sommerwerck wrote:
What you're saying is that if I'm riding on the traditional train,
listening to its whistle I will experience a Doppler effect that is
equal and opposite to that experienced by the whistle - and that's
why I won't hear any change in the tone of the whistle!

That is absolutely correct.

Right! And if you play a 20 Hz and a 2 KHz tone through a full-range
speaker, the cone will move with both signals and the higher frequency
signal will be modulated in frequency by the 20 Hz signal. BUT, if you
mount your head on a driver producing a 20 Hz signal (which does not
even need to be in phase with the first 20 Hz signal), both the 20 Hz
note AND the modulation will be inaudible at your position.

And you'll look really silly, too.

Peace,
Paul

"William Sommerwerck" wrote in message


I'm not afraid of bears, but if I saw one coming my way, I think
common sense would override my lack of fear.

Been there done that. Bears are best seen at a distance, preferable with
natural obstructions in-between if possible.

I've seen a ton more bear crap than bears.

On Wed, 18 Aug 2004 15:10:20 -0700, Bob Cain
wrote:



Arny Krueger wrote:


The distortion does not exist until the sound reaches the receiver.

Arny! That's about the silliest thing I've ever heard from
someone that is techno-savvy.

Bob, surely you've heard the joke about the driver caught running a
red light who told the judge that at the speed he was going the red
light was doppler-shifted to green?*
It's not a green light without the driver going at the
[in]appropriate speed.



Bob

* The punch line is totally off-topic, but as I recall it, the judge
agreed to drop the redlight-running charge, but calculated how fast
the driver had to be going to doppler-shift the red light to green,
and charged the appropriate fine (a dollar for each MPH over the
limit) for how much he was speeding.

-----
http://mindspring.com/~benbradley

George Perfect wrote:

In this place, Bob Cain was recorded saying ...

The Doppler effect requires source and receiver to be spatially separate
and in relative motion. If another body was (say) between source and
receiver but travelling in step with the source, it would not perceive
any Doppler effect.

It is therefore true to say that Doppler occurs only at the receiver.

It is possible to talk about it relative to anything
including the air with no receiver present.


With respect, Bob, that is the key I do believe you are missing.

The Doppler effect has no meaning until it is perceived by a receiver
(listener in this case) spatially separate from and in relative motion
with regard to the source.

Sorry, but that's just wrong. It has measurable
consequences independant of there being a listener. It
isn't like quantum mechanics. They exist whether they are
measured/received or not.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

Steve Maki wrote:


Shouldn't it be possible to accurately describe, without regard to
the receiver, the DIFFERENCE between two waveforms - one with Doppler,
and one without?

Of course it is. If the motion is relative to the medium,
then observable consequences exist in that medium regardless
of whether they are ever interacted with in any way.

It can also be measured by an observer moving relative to
the medium when the wave has not been shifted in it by
motion relative to it, but that does not negate the first
statement.

Not sure, really, what the point of this sub-discussion is
anyway.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

Scott Dorsey wrote:

Right! And if you play a 20 Hz and a 2 KHz tone through a full-range
speaker, the cone will move with both signals and the higher frequency
signal will be modulated in frequency by the 20 Hz signal.

That is not true in the case where the radiation impedence
seen by the piston is the same as the characteristic
impedence of the air and such a situation is physically
realizable.

That isn't what is happening to cause the thing called
Doppler distortion. The intuitive explanation is false.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

Here is the condition for absence of Doppler (1 dimension):
If the source position is described as p(t), then the listener
position must be p(t-d/c)+d, where d is the distance between
source and listener if both are still, and c is the velocity
of propagation.
In other words, at any point in time tau, the listener must
be distance d away from wherever the source was d/c seconds earlier.
(d is a constant, although the distance between source and listener
need not be constant).
Ramifications: there can be relative motion between source and
listener without Doppler, and there can be Doppler without relative
motion between source and listener. Depending upon initial distance
between source and listener, the two could even be moving sinusoidally
out of phase and still the listener may not experience Doppler. Or,
they may move completely in phase, with the listener experiencing
Doppler. This is true because of the finite (nonzero) time of propagation.
Constraints: effects of relativity ignored. Also, the source must
be able to transduce the desired pressure at every given instant. Of
course, the pressure transduced is not independent of the source motion.
If the velocity of motion becomes comparable to the velocity needed to
generate the desired pressure wave, distortion of the signal will result.
This distortion unquestionably can be considered to appear "at the source",
because it is an amplitude distortion, rather than simply a
displacement in time experienced by the listener. Personally, I would never
call this amplitude distortion "Doppler distortion".

Dave



"William Sommerwerck" wrote in message ...
The distortion does not exist until the sound reaches the receiver.

WRONG!

The Doppler shift occurs AT THE SOURCE. If I am moving at the same velocity as
the source, there is a second Doppler shift that cancels out the first.

Doppler shift is produced by motion relative to the medium -- not by relative
motion between the source and the receiver.

THINK... think, think, think... before you lift finger to respond.

Here is the condition for absence of Doppler (1 dimension):
If the source position is described as p(t), then the listener
position must be p(t-d/c)+d, where d is the distance between
source and listener if both are still, and c is the velocity
of propagation.
In other words, at any point in time tau, the listener must
be distance d away from wherever the source was d/c seconds earlier.
(d is a constant, although the distance between source and listener
need not be constant).
Ramifications: there can be relative motion between source and
listener without Doppler, and there can be Doppler without relative
motion between source and listener. Depending upon initial distance
between source and listener, the two could even be moving sinusoidally
out of phase and still the listener may not experience Doppler. Or,
they may move completely in phase, with the listener experiencing
Doppler. This is true because of the finite (nonzero) time of propagation.
Constraints: effects of relativity ignored. Also, the source must
be able to transduce the desired pressure at every given instant. Of
course, the pressure transduced is not independent of the source motion.
If the velocity of motion becomes comparable to the velocity needed to
generate the desired pressure wave, distortion of the signal will result.
This distortion unquestionably can be considered to appear "at the source",
because it is an amplitude distortion, rather than simply a
displacement in time experienced by the listener. Personally, I would never
call this amplitude distortion "Doppler distortion".

This strikes me as utter gobbledygook.

Ben Bradley wrote:

Bob, surely you've heard the joke about the driver caught running a
red light who told the judge that at the speed he was going the red
light was doppler-shifted to green?*
It's not a green light without the driver going at the
[in]appropriate speed.



Bob


* The punch line is totally off-topic, but as I recall it, the judge
agreed to drop the redlight-running charge, but calculated how fast
the driver had to be going to doppler-shift the red light to green,
and charged the appropriate fine (a dollar for each MPH over the
limit) for how much he was speeding.

LOL! Love it. Cleverer trumps clever.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

"William Sommerwerck" wrote in message ...

This strikes me as utter gobbledygook.

Sorry dude, just trying to help you out.

Dave

"The Ghost" wrote in message
om...
"Natalie Drest" wrote in message
...


.........................Everyone knows that boffins who take
themselves too seriously kill a party atmosphere quicker than you can
say
'Frequency Modulation modulation'.

Quite true. And, since only your close-knit group of queers were in
attendance, I wouldn't have fit in anyway.

Ha ha ha!!! You're funny when you get mad- all the veins on your forehead
all stand out. I haven't seen a ghost do that before.

I merely try to help those that appear to need it most. Like you.

Appearances can be deceiving. Have you considered the possibility
that so-called "silly error" was intentionally included in order to
give nitwits like you yet another opportunity to demonstrate to the
world that you have nothing technically substaitive to offer.

I must confess I hadn't. Upon examination though, the proposition seems not
merely ludicrous, but positively paranoid.
Do you always pepper your hypotheses with cunning traps for would-be
pedants? (Maybe you should... because they ARE out to get you, you know....)
Oh, yes I see you do- you've tried with the word 'substaitive'. I'll leave
it well alone, since you're clearly a dangerous man with a fearsome
intellect. (Don't worry, spelling isn't everything...)


I didn't expect you to thank me, I said you ought to. It's called
'manners'.
Look it up.

That's a distinction without a difference. If you have no
expectation, I have no obligation.

Well, is one obliged to have good manners? Some lay that obligation upon
themselves as a matter of their own dignity, others clearly don't... the
choice, as always, is yours. You get to decide the kind of man/queen/boffin
you are.

Furthermore, respect commands
respect. Disrespect is either ignored or reciprocated.

Did I disrespect you by pointing out an error? Sorry if you took it that
way. While I'm at it, I'll apologise for all the other people who
disrespected you by ever offering a suggestion. Must be tough for all you
geniuses- nothing but disrespect all day long.


All the same, I bet you correct the error before you submit your work to
anyone...

Well, you're wrong on all three counts. It wasn't work. It isn't
going to be submitted to anyone. And, the so-called "silly error"
isn't going to be corrected.


That's called 'cutting off your nose to spite your face'. But of course you
knew that already- and everything else.
Including the identity of all those out to get you.

I bet you think my name really is Natalie Drest. I should introduce you
to
my friend Sarah Bellum, she writes all my stuff...

I never did, and please don't. And since we are on the identity
topic, the "queen" label clearly applies, irrespective of one
interprets it.

I'm sorry, you completely lost me there.
Since 'People who can't say what they mean don't mean what they say', I'll
forgive what appears to be confused ranting.
I'm sure you're really not a paranoid, perfectionist, humourless boffin in
need of anger management- you're just a misunderstood lonely person in need
of love.
Perhaps we should have invited you to the party.
Here's the deal: we'll invite you to the next one if you promise not to
postulate any hypotheses.
But you'll have to wear your lab coat.

(Why didn't the ghost come to the party?
Because he had no body to go with!)


--
"I won't go into binary counting here. For further information you can
search the Internet, or cut off all but one of your fingers."
-Roger Nichols

Natalie Drest wrote:

[phenomenal riposte trimmed]

Whoever you are, Natalie, you're one tough broad. :-)


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

This strikes me as utter gobbledygook.

Sorry dude, just trying to help you out.

Thanks, but it made no sense whatever.

"Natalie Drest" wrote in message ...

I must confess I hadn't. Upon examination though, the proposition seems not
merely ludicrous, but positively paranoid.
Do you always pepper your hypotheses with cunning traps for would-be
pedants? (Maybe you should... because they ARE out to get you, you know....)
Oh, yes I see you do- you've tried with the word 'substaitive'. I'll leave
it well alone, since you're clearly a dangerous man with a fearsome
intellect. (Don't worry, spelling isn't everything...)

Congratulations to the queen for finding yet another silly error.
I'll leave it to you to wonder whether it was intentional or not.


Well, is one obliged to have good manners? Some lay that obligation upon
themselves as a matter of their own dignity, others clearly don't... the
choice, as always, is yours. You get to decide the kind of man/queen/boffin
you are.

One aspect of good manners, in which you are clearly lacking, is to
focus on your own behavior and to mind your own business.


Did I disrespect you by pointing out an error? Sorry if you took it that
way.

No, you disrespected yourself, and I followed suit.

That's called 'cutting off your nose to spite your face'. But of course you
knew that already- and everything else.

No, it's called you being too stupid to understand.



I'm sorry, you completely lost me there.


Since 'People who can't say what they mean don't mean what they say', I'll
forgive what appears to be confused ranting.

Get a new record. That one is broken and tiresome.

I'm sure you're really not a paranoid, perfectionist, humourless boffin in
need of anger management- you're just a misunderstood lonely person in need
of love.

At least you are right about one thing.

Perhaps we should have invited you to the party.
Here's the deal: we'll invite you to the next one if you promise not to
postulate any hypotheses.
But you'll have to wear your lab coat.

I don't have a lab coat. No matter, because I won't accept the
invitation anyway.

(Why didn't the ghost come to the party?
Because he had no body to go with!)

No, it's because ghosts don't travel in queer circles.

On Thu, 19 Aug 2004 07:19:10 -0700, "William Sommerwerck"
wrote:

Relative motion between source and observer is NOT required for there to be
Doppler shift. Doppler shift occurs WHENEVER the source is moving.

It is whether the listener is in motion with respect to the source that
determines whether he will hear the Doppler shift.

????

Chris Hornbeck

Chris Hornbeck wrote:

On Thu, 19 Aug 2004 07:19:10 -0700, "William Sommerwerck"
wrote:


Relative motion between source and observer is NOT required for there to be
Doppler shift. Doppler shift occurs WHENEVER the source is moving.

It is whether the listener is in motion with respect to the source that
determines whether he will hear the Doppler shift.


????

Well, it's true, isn't it? Let's say the wave propagates at some
speed V. Let's say the sound source is moving through the air
at speed 1/2*V. The wave is then causing the air pressure to
oscillate at twice the frequency that the driver is moving. If
we assume no relative motion between sound source and listener,
then the listener is still hearing the same frequency the driver
is oscillating at. The rate of oscillation of the air pressure
is only the same as the rate of oscillation of the sound source
if the sound source isn't moving.

So, I don't know if William's statement was relevant to anything
or not, but I can't see anything untrue about it either.

- Logan

Has anyone estimated the Doppler shift on the speaker of the TV that
Keith Moon threw out the 7th floor hotel room window?

Gary wrote:

Has anyone estimated the Doppler shift on the speaker of the TV that
Keith Moon threw out the 7th floor hotel room window?

Not yet, but it does raise the interesting question of the
nature of Doppler mixing from a constantly accelerating Tx.
I know, I know, who else but me would be interested in
that. :-)


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein