The Doppler Effect......

[Brian37]

Don't ask me about the actuall formula or answer with it. Pretty sure it will make my head explode. 

But if I am not correct, the overall concept is this.

The further away a sound, is approaching you, say like a fire engine with siren's on, is going to be lower in volume from your point of view, the further away it is from you. But the closer it approaches the louder you will precieve it, but after it passes you, the lower the volume gets from your point of view as it passes off in the distance? 

Not based on formula, just overall concept, am I getting that correct?

[Jackalope]

It's not volume, it's pitch.

[Brian37]

It's not volume, it's pitch.

Ok, without making my head explode, what is the difference between volume and pitch?

Because no matter my motion, standing still, or being in motion myself, I do know somthing off in the distance I am not going to percieve as being as loud as something right next to me. And as well, after it passes me and moves off in the distance it I will not percieve it as loud as if both of us were stationary right next to each other.

[onlinebiker]

It' s both.

Amplitude (volume) and frequency ( pitch) increase as the source approaches the observer then diminish after it heads away from the observer.

[Jackalope]

It's not volume, it's pitch.

Ok, without making my head explode, what is the difference between volume and pitch?

Because no matter my motion, standing still, or being in motion myself, I do know somthing off in the distance I am not going to percieve as being as loud as something right next to me. And as well, after it passes me and moves off in the distance it I will not percieve it as loud as if both of us were stationary right next to each other.

Yes, all if that is true, but none of it describes the Doppler effect.

The Doppler effect describes how the wavelength of a sound (or light) emitted by a source is stretched or compressed as it either recedes from or approaches toward you. Lower wavelength sound = lower pitch. Thing about a guitar's strings. The larger strings create sounds lower in pitch because they vibrate at a lower frequency.

[Brian37]

Ok, how about this, lets take all things as an example being equal in distance from the time  the vehicle off in the distance approaches, when you first notice it, then at your most aware perception, when it is passing you, what is the difference between the time you notice it, to the time it gets equal distance after it passes you? 

Without the formulas, it seems to me, that the further away and object is, the longer the soundwaves are between peaks, but the closer they get to the observer, the more frequent and bunched up they are percieved by the observer, but after they pass the observer, the more spread out the waves become, thus giving the observer the same perception of more being lower volume as when they were off in the distance when they first aproached you?

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Ok, without making my head explode, what is the difference between volume and pitch?

Because no matter my motion, standing still, or being in motion myself, I do know somthing off in the distance I am not going to percieve as being as loud as something right next to me. And as well, after it passes me and moves off in the distance it I will not percieve it as loud as if both of us were stationary right next to each other.

Yes, all if that is true, but none of it describes the Doppler effect.

The Doppler effect describes how the wavelength of a sound (or light) emitted by a source is stretched or compressed as it either recedes from or approaches toward you.  Lower wavelength sound = lower pitch.  Thing about a guitar's strings.  The larger strings create sounds lower in pitch because they vibrate at a lower frequency.

Ok, so

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Ok, how about this, lets take all things as an example being equal in distance from the time  the vehicle off in the distance approaches, when you first notice it, then at your most aware perception, when it is passing you, what is the difference between the time you notice it, to the time it gets equal distance after it passes you? 

Without the formulas, it seems to me, that the further away and object is, the longer the soundwaves are between peaks, but the closer they get to the observer, the more frequent and bunched up they are percieved by the observer, but after they pass the observer, the more spread out the waves become, thus giving the observer the same perception of more being lower volume as when they were off in the distance when they first aproached you?

---

Yes, all if that is true, but none of it describes the Doppler effect.

The Doppler effect describes how the wavelength of a sound (or light) emitted by a source is stretched or compressed as it either recedes from or approaches toward you.  Lower wavelength sound = lower pitch.  Thing about a guitar's strings.  The larger strings create sounds lower in pitch because they vibrate at a lower frequency.

Ok, so

Ok so when we talk about "stretched" vs "compressed" the "streched" point of view(observation)is when the light/sound is further away, and the "compressed" point of view(observation) is when two objects are closer together?

Could one compare this "doppler" when talking about sound or light waves, being like the difference between a streched Slinky toy verses a compressed slinky toy? And the "pitch" in a stretched Slinky is the sound/light being further away, and the "compressed" Slinkey" being the closer or next to proximity to the observer?

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Ok another question. All things considered side by side. I know it is possible for a guitar solo to be as knife peircing as Norman Bates stabbing the woman in the hotel shower (and yes, I know that was violins). But I also know that the "BUMB BUMB BUMP Anotherone bites the dust" can be just as loud. 

I can only assume the "Amplitude" applies to both "pitches"? Is this why I know about both "woofers and tweeters" in regards to old school home and car stereos?

I know tweeters projected the high peircing notes, and the woofers put out the low notes, like base guitars and base drums.

[Anomalocaris]

Think of it this way.    The speed of sound in air is governed by the density of the air, not by any attribute of the device that made the sound.     So If a car is moving through air from left to right, The sound propagating ahead and behind the car moves at the same speed relative to the air, not to the car.    

Let’s say sound propagate through air at 1000 feet per second.    Let’s say the car moves from left to right at 100 feet/sec.    Now imagine if the frequency of the sound emitter by the car is 100 beats a second.     The 1st beat the car made would have traveled 10 feet through the air to both the left and right by the time the second beat is emitted.    But during the intervening time the car would have also traveled 1 foot or the right.  

So when the second beat is emitted by the car, the second beat would follow the first beat not by 10 feet, but only 9 feet at the right, but 11 feet at the left because the car itself has moved in between the beats.

So what does that mean?    Now imagine you are stationary WRT the air to the right of the car.   The beats of the sound is arriving at your location at 1000 feet per second, separated by 9 feet between each beat.    What is the frenquecy you hear?  It is 1000/9=111 beats a second.     Now imagine you are a stationary listener to,the left of the car.   The beats of the sound is arriving at your location at 1000 feet per second, separated by 11 feet between each beat.    What is the frenquecy you hear?  It is 1000/11=90 beats a second.

Frequency increase in front of a moving emitter, and decrease behind a moving emitter, as measured by an listener at rest with respect to the medium in which the wave travels.    

So that is Doppler effect.

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It's not volume, it's pitch.

Ok, without making my head explode, what is the difference between volume and pitch?

Because no matter my motion, standing still, or being in motion myself, I do know somthing off in the distance I am not going to percieve as being as loud as something right next to me. And as well, after it passes me and moves off in the distance it I will not percieve it as loud as if both of us were stationary right next to each other.

Volume is how loud the scream is.  Pitch is how sharp the scream is.

---

It's not volume, it's pitch.

Ok, without making my head explode, what is the difference between volume and pitch?

Because no matter my motion, standing still, or being in motion myself, I do know somthing off in the distance I am not going to percieve as being as loud as something right next to me. And as well, after it passes me and moves off in the distance it I will not percieve it as loud as if both of us were stationary right next to each other.

Imagine someone is screaming.   Volume is how loud the scream is.  Pitch is how sharp the scream is.

[HappySkeptic]

Don't ask me about the actuall formula or answer with it. Pretty sure it will make my head explode. 

But if I am not correct, the overall concept is this.

The further away a sound, is approaching you, say like a fire engine with siren's on, is going to be lower in volume from your point of view, the further away it is from you. But the closer it approaches the louder you will precieve it, but after it passes you, the lower the volume gets from your point of view as it passes off in the distance? 

Not based on formula, just overall concept, am I getting that correct?

When a sound source is moving toward you, its frequency or pitch is higher (think soprano instead of bass).

When a sound source is moving away from you, its frequency (or pitch) is lower.

You also get a higher volume when a sound source is close to you.  If someone hits a bell right in front of you, its louder than if it is down the street.

The two effects together explain the sound of a fire engine coming toward you and going away.

[onlinebiker]

Don't ask me about the actuall formula or answer with it. Pretty sure it will make my head explode. 

But if I am not correct, the overall concept is this.

The further away a sound, is approaching you, say like a fire engine with siren's on, is going to be lower in volume from your point of view, the further away it is from you. But the closer it approaches the louder you will precieve it, but after it passes you, the lower the volume gets from your point of view as it passes off in the distance? 

Not based on formula, just overall concept, am I getting that correct?

When a sound source is moving toward you, its frequency or pitch is higher (think soprano instead of bass).

When a sound source is moving away from you, its frequency (or pitch) is lower.

You also get a higher volume when a sound source is close to you.  If someone hits a bell right in front of you, its louder than if it is down the street.

The two effects together explain the sound of a fire engine coming toward you and going away.

No.

Doppler effect is obsevable only from an observer' s point of view.

That is - the audio frequency of the moving object (like a train coming towards you) in reality is constant - but APPEARS to the observer as ascending in frequency.


The same can be observed by a moving observer and a stationary source of sound.


Trust me - I KNOW Doppler effect.

I was taught it back in 1981 when I was a Coast Guard Radioman - and SARSAT went on line. SARSAT uses Doppler shift - observing an EPIRB on the ground and by measuring the intensity of the doppler shift can calculate two possible positions of the EPIRB transmitter on either side of the satellite' s polar track....

[The Grand Nudger]

Without making your head explode - imagine an ambulance is emitting a wave. The wave itself is uniform in all directions. The ambulance, however, is moving toward you - and so the point of emanation for the wave is piling up on itself, making the waves ahead tighter, and making the waves behind looser.

Just like if I walked toward you making waves in a pool. If I push a ball down into the water every second while stationary, you'll see the uniform wave. If I push the ball down every second while moving forward a foot every second, you'll see the leading edge pile up and the trailing edge spread out.