Re: [music-dsp] intensity of Doppler effect

[Andy Farnell]

This is a quite interesting, and less than obvious question,
that I keep on thinking about.

My thoughts turned to the phenomena of sonic boom. Where the velocity of a 
source is equal to c, the 
propagation velocity of the medium, then we have an extreme limit of Doppler, 
in which all the acoustic energy 
is condensed into a single high amplitude solitary front. Only at the point 
where the listener is co-located 
with the source, or passes through the trailing Mach cone, is a single high 
amplitude impulse heard.

Can Doppler be interpreted in terms of Mach?  They seem to tie together in 
relativistic wave physics.  If so, 
given this extreme interpretation of Doppler, does amplitude change for other 
cases, where source velocity is 
just less than c?  And by extension, values much less than c?

But for sound we need to remove extraenuous factors.  Trivially, something 
sounds louder if its moving towards 
you because it is "getting closer". We need to remove geometric loss by 
assuming a source at a very large 
(infinite) distance such that the waves at the receiver are still Huygens 
constructions but are effectively 
planar (analogy of sunlight through pinhole). Then we need to remove all real 
gas laws (adiabatic, viscous 
losses) for the medium, making our acoustic waves perfect (Riemann) plane 
waves. Now, if an object radiating 10 
Watts of energy stays in the same place, and is observed at some distance D, 
for 10 seconds, the receiver gets 
all of that energy from thr source incident upon it, 10 Watts of acoustic 
energy, and during the time it 
absorbs 100 Joules of energy. If we do not have to assume the rest of energy 
radiates away in other directions, 
all of the energy emitted from our perfect "sound laser" must be received by 
the observer.

Then we can use the pitcher and catcher analogy often used in other relativity 
thought experiments.

Also, there must be a certain energetic "channel capacity" (pitched balls 
already in the air). If D > 340m and 
the stationary source begins emitting energy for one second, then ceases, the 
medium of the channel will 
contain a one second (10 Joules) burst of energy.

If the channel is "already full", and during the next moments either source or 
receiver move toward one 
another, then the receiver must absorb what is in the channel plus energy 
emitted by the source during that 
time (catcher has to collect more pitched balls per second).

So far we are taking the extra energy to be accounted for by increase in 
frequency, as for Planck's equations, 
(Evan already mentioned particle velocity and the fact that particle k.e. = 
1/2mv^2, but care is needed when 
relating this to "intensity", as in acoustics we may mistakenly involve 
perceptual (psychoacoustic) factors. 
What we are really interested in, is whether a measurable increase in amplitude 
occurs in addition to the 
expected frequency change.

As I was researching my reading landed me here:

en.wikipedia.org/wiki/Relativistic_Doppler_effect

Where I found this passage, which uses terms unfamiliar in acoustics, but I am 
sure a capable mathematician can 
connect the dots...

"Doppler effect on intensity[edit]

The Doppler effect (with arbitrary direction) also modifies the perceived 
source intensity: this can be 
expressed concisely by the fact that sourcefstrength divided by the cube of the 
frequency is{a Lorentz 
invariant^[5] (here, "source strength" refers to spectral intensity in 
frequency, i.e., power per unit solid 
angle and per unit frequency, expressed in watts per steradian per hertz; for 
spectral intensity in wavelength, 
the cube should be replaced by a fifth power). This implies that the total 
radiant intensity (summing over all 
frequencies) is multiplied by the fourth power of the Doppler factor for 
frequency."

So, I guess the question is "are longitudinal acoustic pressure waves subject 
to relativistic Doppler 
effects?". I believe the answer is yes, and the OP usefully points out that 
most classical sound textbooks omit 
the amplitude aspect of the effect.

It have some important implications in vehicular noise models, and is likely 
already a component of more 
sophisticated models.

best,
Andy



On Thu, Oct 12, 2017 at 11:13:55AM -0400, Ethan Fenn wrote:
> >
> > Since only the speed difference between sender and receiver does matter:
> > No.
> > This article is pretty thorough on this topic:
> > https://en.wikipedia.org/wiki/Doppler_effect
> 
> 
> Well, according to the article the pitch change will not be identical in
> those two scenarios. But it will be approximately the same for speeds well
> below the speed of sound.
> 
> -Ethan
> 
> 
> 
> On Thu, Oct 12, 2017 at 11:02 AM, STEFFAN DIEDRICHSEN 
> wrote:
> 
> >
> > On 12.10.2017|KW41, at 16:31, Phil Burk  wrote:
> >
> > Do the two cases sound different?
> >
> >
> > Since only the speed difference between sender and receiver does matter:
> > No.
> >
> > This 

Re: [music-dsp] intensity of Doppler effect

[Ethan Fenn]

>
> Since only the speed difference between sender and receiver does matter:
> No.
> This article is pretty thorough on this topic:
> https://en.wikipedia.org/wiki/Doppler_effect


Well, according to the article the pitch change will not be identical in
those two scenarios. But it will be approximately the same for speeds well
below the speed of sound.

-Ethan



On Thu, Oct 12, 2017 at 11:02 AM, STEFFAN DIEDRICHSEN 
wrote:

>
> On 12.10.2017|KW41, at 16:31, Phil Burk  wrote:
>
> Do the two cases sound different?
>
>
> Since only the speed difference between sender and receiver does matter:
> No.
>
> This article is pretty thorough on this topic:
> https://en.wikipedia.org/wiki/Doppler_effect
>
> Best,
>
> Steffan
>
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Re: [music-dsp] intensity of Doppler effect

[Renato Fabbri]

Thanks Evan,

I'll try to write that (and other bits of our discussion)
mathematically so we can have some consensus
and then send it to a Peer-Review.

For a week or so lets see if we have other understandings
about the phenomenon and if other members of the list
also have thoughts on this.

I am particularly inclined to not trust whatever theoretical
discourse we make before we have some peer review
because it seems not so obvious (at least at the moment).

R.


On Wed, Oct 11, 2017 at 2:22 PM, Evan Balster  wrote:

> Hey, Renato —
>
> Per the other recent thread on this topic, the power of a sound wave is
> proportional to the square of (frequency x displacement).  So even though
> there's no increase in displacement, the doppler effect for an approaching
> object will cause an increase in its sound's AC power (and loudness, to an
> ideal listener, and signal amplitude, to a microphone).
>
> Summarizing the other thread:  Microphone voltage typically corresponds to
> the differential of the diaphragm's displacement (because magnet/coil
> movement causes electrical induction).  Because this differential (dx/dt
> where x=sin(ωt)) becomes steeper as frequency increases, an increase in
> sound frequency will produce an increase in signal amplitude even as the
> air displacement remains constant.  This is why we measure power as a
> simple RMS in signal processing systems even though it's
> frequency-dependent in physics.
>
> – Evan Balster
> creator of imitone 
>
> On Wed, Oct 11, 2017 at 8:25 AM, Renato Fabbri 
> wrote:
>
>> Dear Music-DSPers,
>>
>> These considerations about the intensity of the Doppler
>> effect is quite estrange and seems really to have not
>> received a note in the literature, probably IMHO because
>> it only changes the DC component (mean pressure)
>> and thus has not been detected in experiments.
>>
>> Therefore, if we can manage to give a decent
>> account of it, I am willing to write a short note
>> and upload to arXiv.
>> And maybe send it to a minor conference
>> to which I attend or a minor journal.
>> (Citing this group and in co-authorship
>> with whomever helps in the derivation
>> of the description.)
>>
>> Also, I've found some posts with the same question
>> in online forums: it seems to be a quite
>> often difficulty.
>>
>> Best,
>> R.
>>
>>
>> On Mon, Oct 9, 2017 at 2:30 PM, Renato Fabbri 
>> wrote:
>>
>>> Ok, I think I managed to better express the problem.
>>>
>>> the power of the wave is P = DE/DT (D is Delta, E is energy, T is time).
>>> If the receiver is not moving and the source is moving
>>> in the direction of the receiver with speed s,
>>> and DT=1:
>>>
>>> DE2 = DE + DE(s/c) + mv^2/2
>>>
>>> (c is the sonic speed ~340)
>>>
>>> The first term is the energy emitted by the source.
>>> The second term is due to the additional amount of the wave
>>> that is being received in the same time span.
>>> The third term is just the kinetic energy.
>>>
>>> Naively, one might think that:
>>> P2 = DE2/DT
>>>
>>> and the decibel difference is:
>>> dB = 10log_10(DE2/DE)
>>>
>>> But.
>>> What we hear is the pressure oscillation amplitude,
>>> with the DC component (bias, offset) not being relevant.
>>>
>>> So, my conclusion, at the moment, is that,
>>> in fact, the loudness difference we have in the Doppler
>>> effect is only due to the distance between the source and
>>> the receiver.
>>> This is because the second and third terms in DE2
>>> really exist but introduce only a DC component.
>>> The DC component varies but such variation
>>> should yield quite
>>> an irrelevant contribution to the intensity of the wave.
>>>
>>> *If* all these thoughts are right,
>>> then the question still remains:
>>> what (probably negligible) is the contribution
>>> of the variation of the DC component
>>> to the intensity (or power) of the wave.
>>>
>>> (???)
>>>
>>> Best,
>>> R.
>>>
>>>
>>>
>>>
>>> On Mon, Oct 9, 2017 at 8:24 AM, Renato Fabbri 
>>> wrote:
>>>


 On Sun, Oct 8, 2017 at 11:29 PM, Evan Balster  wrote:

> Hey, Renato —
>
> .
>


> Imagine a 330-meter-long wavefront moving right at 330 meters per
> second toward a quarter-sized object; if the object is still, it receives
> sound sound energy on its surface over the course of one second.  If it's
> moving left, it received the energy over a smaller window of time,
> experiencing it as a higher frequency.
>

 That's about it: if one is receiving the same amount of energy over a
 shorter time span,
 (my hint is that) there should be an increase in the power, intensity
 and thus loudness
 (with the care to notice that loudness depends on more things so its
 increase is not assured).

 R.


> – Evan Balster
> creator of imitone
> 

Re: [music-dsp] intensity of Doppler effect

[Evan Balster]

Hey, Renato —

Per the other recent thread on this topic, the power of a sound wave is
proportional to the square of (frequency x displacement).  So even though
there's no increase in displacement, the doppler effect for an approaching
object will cause an increase in its sound's AC power (and loudness, to an
ideal listener, and signal amplitude, to a microphone).

Summarizing the other thread:  Microphone voltage typically corresponds to
the differential of the diaphragm's displacement (because magnet/coil
movement causes electrical induction).  Because this differential (dx/dt
where x=sin(ωt)) becomes steeper as frequency increases, an increase in
sound frequency will produce an increase in signal amplitude even as the
air displacement remains constant.  This is why we measure power as a
simple RMS in signal processing systems even though it's
frequency-dependent in physics.

– Evan Balster
creator of imitone 

On Wed, Oct 11, 2017 at 8:25 AM, Renato Fabbri 
wrote:

> Dear Music-DSPers,
>
> These considerations about the intensity of the Doppler
> effect is quite estrange and seems really to have not
> received a note in the literature, probably IMHO because
> it only changes the DC component (mean pressure)
> and thus has not been detected in experiments.
>
> Therefore, if we can manage to give a decent
> account of it, I am willing to write a short note
> and upload to arXiv.
> And maybe send it to a minor conference
> to which I attend or a minor journal.
> (Citing this group and in co-authorship
> with whomever helps in the derivation
> of the description.)
>
> Also, I've found some posts with the same question
> in online forums: it seems to be a quite
> often difficulty.
>
> Best,
> R.
>
>
> On Mon, Oct 9, 2017 at 2:30 PM, Renato Fabbri 
> wrote:
>
>> Ok, I think I managed to better express the problem.
>>
>> the power of the wave is P = DE/DT (D is Delta, E is energy, T is time).
>> If the receiver is not moving and the source is moving
>> in the direction of the receiver with speed s,
>> and DT=1:
>>
>> DE2 = DE + DE(s/c) + mv^2/2
>>
>> (c is the sonic speed ~340)
>>
>> The first term is the energy emitted by the source.
>> The second term is due to the additional amount of the wave
>> that is being received in the same time span.
>> The third term is just the kinetic energy.
>>
>> Naively, one might think that:
>> P2 = DE2/DT
>>
>> and the decibel difference is:
>> dB = 10log_10(DE2/DE)
>>
>> But.
>> What we hear is the pressure oscillation amplitude,
>> with the DC component (bias, offset) not being relevant.
>>
>> So, my conclusion, at the moment, is that,
>> in fact, the loudness difference we have in the Doppler
>> effect is only due to the distance between the source and
>> the receiver.
>> This is because the second and third terms in DE2
>> really exist but introduce only a DC component.
>> The DC component varies but such variation
>> should yield quite
>> an irrelevant contribution to the intensity of the wave.
>>
>> *If* all these thoughts are right,
>> then the question still remains:
>> what (probably negligible) is the contribution
>> of the variation of the DC component
>> to the intensity (or power) of the wave.
>>
>> (???)
>>
>> Best,
>> R.
>>
>>
>>
>>
>> On Mon, Oct 9, 2017 at 8:24 AM, Renato Fabbri 
>> wrote:
>>
>>>
>>>
>>> On Sun, Oct 8, 2017 at 11:29 PM, Evan Balster  wrote:
>>>
 Hey, Renato —

 .

>>>
>>>
 Imagine a 330-meter-long wavefront moving right at 330 meters per
 second toward a quarter-sized object; if the object is still, it receives
 sound sound energy on its surface over the course of one second.  If it's
 moving left, it received the energy over a smaller window of time,
 experiencing it as a higher frequency.

>>>
>>> That's about it: if one is receiving the same amount of energy over a
>>> shorter time span,
>>> (my hint is that) there should be an increase in the power, intensity
>>> and thus loudness
>>> (with the care to notice that loudness depends on more things so its
>>> increase is not assured).
>>>
>>> R.
>>>
>>>
 – Evan Balster
 creator of imitone
 

 On Sun, Oct 8, 2017 at 6:26 PM, Renato Fabbri 
 wrote:

> Ok that the Doppler effect changes the frequency of the received sound.
>
> But, at the same time, it seems to me that there *might* be a change in
> the intensity of the wave, not due to the change in the relative
> localization
> of the source to the receiver, but due to the relative speed.
>
> I already searched about this a few times in the past years
> and found nothing.
> Maybe because the 

Re: [music-dsp] intensity of Doppler effect

[Renato Fabbri]

Dear Music-DSPers,

These considerations about the intensity of the Doppler
effect is quite estrange and seems really to have not
received a note in the literature, probably IMHO because
it only changes the DC component (mean pressure)
and thus has not been detected in experiments.

Therefore, if we can manage to give a decent
account of it, I am willing to write a short note
and upload to arXiv.
And maybe send it to a minor conference
to which I attend or a minor journal.
(Citing this group and in co-authorship
with whomever helps in the derivation
of the description.)

Also, I've found some posts with the same question
in online forums: it seems to be a quite
often difficulty.

Best,
R.


On Mon, Oct 9, 2017 at 2:30 PM, Renato Fabbri 
wrote:

> Ok, I think I managed to better express the problem.
>
> the power of the wave is P = DE/DT (D is Delta, E is energy, T is time).
> If the receiver is not moving and the source is moving
> in the direction of the receiver with speed s,
> and DT=1:
>
> DE2 = DE + DE(s/c) + mv^2/2
>
> (c is the sonic speed ~340)
>
> The first term is the energy emitted by the source.
> The second term is due to the additional amount of the wave
> that is being received in the same time span.
> The third term is just the kinetic energy.
>
> Naively, one might think that:
> P2 = DE2/DT
>
> and the decibel difference is:
> dB = 10log_10(DE2/DE)
>
> But.
> What we hear is the pressure oscillation amplitude,
> with the DC component (bias, offset) not being relevant.
>
> So, my conclusion, at the moment, is that,
> in fact, the loudness difference we have in the Doppler
> effect is only due to the distance between the source and
> the receiver.
> This is because the second and third terms in DE2
> really exist but introduce only a DC component.
> The DC component varies but such variation
> should yield quite
> an irrelevant contribution to the intensity of the wave.
>
> *If* all these thoughts are right,
> then the question still remains:
> what (probably negligible) is the contribution
> of the variation of the DC component
> to the intensity (or power) of the wave.
>
> (???)
>
> Best,
> R.
>
>
>
>
> On Mon, Oct 9, 2017 at 8:24 AM, Renato Fabbri 
> wrote:
>
>>
>>
>> On Sun, Oct 8, 2017 at 11:29 PM, Evan Balster  wrote:
>>
>>> Hey, Renato —
>>>
>>> .
>>>
>>
>>
>>> Imagine a 330-meter-long wavefront moving right at 330 meters per second
>>> toward a quarter-sized object; if the object is still, it receives sound
>>> sound energy on its surface over the course of one second.  If it's moving
>>> left, it received the energy over a smaller window of time, experiencing it
>>> as a higher frequency.
>>>
>>
>> That's about it: if one is receiving the same amount of energy over a
>> shorter time span,
>> (my hint is that) there should be an increase in the power, intensity and
>> thus loudness
>> (with the care to notice that loudness depends on more things so its
>> increase is not assured).
>>
>> R.
>>
>>
>>> – Evan Balster
>>> creator of imitone
>>> 
>>>
>>> On Sun, Oct 8, 2017 at 6:26 PM, Renato Fabbri 
>>> wrote:
>>>
 Ok that the Doppler effect changes the frequency of the received sound.

 But, at the same time, it seems to me that there *might* be a change in
 the intensity of the wave, not due to the change in the relative
 localization
 of the source to the receiver, but due to the relative speed.

 I already searched about this a few times in the past years
 and found nothing.
 Maybe because the intensity of the wave just doesn't change
 for the emitted energy is conserved. (?)
 And all we are left with is the standard change in the
 intensity of the wave due to the distance.

 Any thoughts?

 R.

 --
 Renato Fabbri
 GNU/Linux User #479299
 labmacambira.sourceforge.net

 ___
 dupswapdrop: music-dsp mailing list
 music-dsp@music.columbia.edu
 https://lists.columbia.edu/mailman/listinfo/music-dsp

>>>
>>>
>>> ___
>>> dupswapdrop: music-dsp mailing list
>>> music-dsp@music.columbia.edu
>>> https://lists.columbia.edu/mailman/listinfo/music-dsp
>>>
>>
>>
>>
>> --
>> Renato Fabbri
>> GNU/Linux User #479299
>> labmacambira.sourceforge.net
>>
>
>
>
> --
> Renato Fabbri
> GNU/Linux User #479299
> labmacambira.sourceforge.net
>



-- 
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GNU/Linux User #479299
labmacambira.sourceforge.net
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Re: [music-dsp] intensity of Doppler effect

[Renato Fabbri]

Ok, I think I managed to better express the problem.

the power of the wave is P = DE/DT (D is Delta, E is energy, T is time).
If the receiver is not moving and the source is moving
in the direction of the receiver with speed s,
and DT=1:

DE2 = DE + DE(s/c) + mv^2/2

(c is the sonic speed ~340)

The first term is the energy emitted by the source.
The second term is due to the additional amount of the wave
that is being received in the same time span.
The third term is just the kinetic energy.

Naively, one might think that:
P2 = DE2/DT

and the decibel difference is:
dB = 10log_10(DE2/DE)

But.
What we hear is the pressure oscillation amplitude,
with the DC component (bias, offset) not being relevant.

So, my conclusion, at the moment, is that,
in fact, the loudness difference we have in the Doppler
effect is only due to the distance between the source and
the receiver.
This is because the second and third terms in DE2
really exist but introduce only a DC component.
The DC component varies but such variation
should yield quite
an irrelevant contribution to the intensity of the wave.

*If* all these thoughts are right,
then the question still remains:
what (probably negligible) is the contribution
of the variation of the DC component
to the intensity (or power) of the wave.

(???)

Best,
R.




On Mon, Oct 9, 2017 at 8:24 AM, Renato Fabbri 
wrote:

>
>
> On Sun, Oct 8, 2017 at 11:29 PM, Evan Balster  wrote:
>
>> Hey, Renato —
>>
>> .
>>
>
>
>> Imagine a 330-meter-long wavefront moving right at 330 meters per second
>> toward a quarter-sized object; if the object is still, it receives sound
>> sound energy on its surface over the course of one second.  If it's moving
>> left, it received the energy over a smaller window of time, experiencing it
>> as a higher frequency.
>>
>
> That's about it: if one is receiving the same amount of energy over a
> shorter time span,
> (my hint is that) there should be an increase in the power, intensity and
> thus loudness
> (with the care to notice that loudness depends on more things so its
> increase is not assured).
>
> R.
>
>
>> – Evan Balster
>> creator of imitone
>> 
>>
>> On Sun, Oct 8, 2017 at 6:26 PM, Renato Fabbri 
>> wrote:
>>
>>> Ok that the Doppler effect changes the frequency of the received sound.
>>>
>>> But, at the same time, it seems to me that there *might* be a change in
>>> the intensity of the wave, not due to the change in the relative
>>> localization
>>> of the source to the receiver, but due to the relative speed.
>>>
>>> I already searched about this a few times in the past years
>>> and found nothing.
>>> Maybe because the intensity of the wave just doesn't change
>>> for the emitted energy is conserved. (?)
>>> And all we are left with is the standard change in the
>>> intensity of the wave due to the distance.
>>>
>>> Any thoughts?
>>>
>>> R.
>>>
>>> --
>>> Renato Fabbri
>>> GNU/Linux User #479299
>>> labmacambira.sourceforge.net
>>>
>>> ___
>>> dupswapdrop: music-dsp mailing list
>>> music-dsp@music.columbia.edu
>>> https://lists.columbia.edu/mailman/listinfo/music-dsp
>>>
>>
>>
>> ___
>> dupswapdrop: music-dsp mailing list
>> music-dsp@music.columbia.edu
>> https://lists.columbia.edu/mailman/listinfo/music-dsp
>>
>
>
>
> --
> Renato Fabbri
> GNU/Linux User #479299
> labmacambira.sourceforge.net
>



-- 
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labmacambira.sourceforge.net
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Re: [music-dsp] intensity of Doppler effect

[Renato Fabbri]

On Sun, Oct 8, 2017 at 11:29 PM, Evan Balster  wrote:

> Hey, Renato —
>
> .
>


> Imagine a 330-meter-long wavefront moving right at 330 meters per second
> toward a quarter-sized object; if the object is still, it receives sound
> sound energy on its surface over the course of one second.  If it's moving
> left, it received the energy over a smaller window of time, experiencing it
> as a higher frequency.
>

That's about it: if one is receiving the same amount of energy over a
shorter time span,
(my hint is that) there should be an increase in the power, intensity and
thus loudness
(with the care to notice that loudness depends on more things so its
increase is not assured).

R.


> – Evan Balster
> creator of imitone
> 
>
> On Sun, Oct 8, 2017 at 6:26 PM, Renato Fabbri 
> wrote:
>
>> Ok that the Doppler effect changes the frequency of the received sound.
>>
>> But, at the same time, it seems to me that there *might* be a change in
>> the intensity of the wave, not due to the change in the relative
>> localization
>> of the source to the receiver, but due to the relative speed.
>>
>> I already searched about this a few times in the past years
>> and found nothing.
>> Maybe because the intensity of the wave just doesn't change
>> for the emitted energy is conserved. (?)
>> And all we are left with is the standard change in the
>> intensity of the wave due to the distance.
>>
>> Any thoughts?
>>
>> R.
>>
>> --
>> Renato Fabbri
>> GNU/Linux User #479299
>> labmacambira.sourceforge.net
>>
>> ___
>> dupswapdrop: music-dsp mailing list
>> music-dsp@music.columbia.edu
>> https://lists.columbia.edu/mailman/listinfo/music-dsp
>>
>
>
> ___
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> music-dsp@music.columbia.edu
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>



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labmacambira.sourceforge.net
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Re: [music-dsp] intensity of Doppler effect

[Evan Balster]

Hey, Renato —

Kinetic energy is proportional to velocity squared times mass.  The maximum
speed of an oscillating particle of air is proportional to both the
amplitude (or displacement) of the wave and the frequency.  Vibrating
further = moving faster.  Vibrating faster = moving faster.

If some sound wave is hitting a surface and displacing it, the same rule
applies.  Velocity is proportional to displacement times frequency, and
energy is proportional to the square of that.  The doppler effect increases
the frequency of the wave, and thus the rate at which energy is delivered
(the power).

The doppler effect isn't magically increasing or decreasing the energy in
the sound wave.  We're just receiving that energy faster because we're
moving in the opposite direction.

Imagine a 330-meter-long wavefront moving right at 330 meters per second
toward a quarter-sized object; if the object is still, it receives sound
sound energy on its surface over the course of one second.  If it's moving
left, it received the energy over a smaller window of time, experiencing it
as a higher frequency.

– Evan Balster
creator of imitone 

On Sun, Oct 8, 2017 at 6:26 PM, Renato Fabbri 
wrote:

> Ok that the Doppler effect changes the frequency of the received sound.
>
> But, at the same time, it seems to me that there *might* be a change in
> the intensity of the wave, not due to the change in the relative
> localization
> of the source to the receiver, but due to the relative speed.
>
> I already searched about this a few times in the past years
> and found nothing.
> Maybe because the intensity of the wave just doesn't change
> for the emitted energy is conserved. (?)
> And all we are left with is the standard change in the
> intensity of the wave due to the distance.
>
> Any thoughts?
>
> R.
>
> --
> Renato Fabbri
> GNU/Linux User #479299
> labmacambira.sourceforge.net
>
> ___
> dupswapdrop: music-dsp mailing list
> music-dsp@music.columbia.edu
> https://lists.columbia.edu/mailman/listinfo/music-dsp
>
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[music-dsp] intensity of Doppler effect

[Renato Fabbri]

Ok that the Doppler effect changes the frequency of the received sound.

But, at the same time, it seems to me that there *might* be a change in
the intensity of the wave, not due to the change in the relative
localization
of the source to the receiver, but due to the relative speed.

I already searched about this a few times in the past years
and found nothing.
Maybe because the intensity of the wave just doesn't change
for the emitted energy is conserved. (?)
And all we are left with is the standard change in the
intensity of the wave due to the distance.

Any thoughts?

R.

-- 
Renato Fabbri
GNU/Linux User #479299
labmacambira.sourceforge.net
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