Sound propagation with altitude/height

[williamcarter]

Let's say we have a 3 floor/level building , and someone is making noise outside, i.e: Playing guitar, given that all the building has the same sound isolation everywhere, what can you say about the sound propagation? we have 2 cases a) when windows opened b) when windows closed

Will the people living on 1st floor will be more affected by sound(will they hear it more intense), compared with the people living on 2nd floor, will there be any difference in terms of noise?

Thank you in advance.

 

[phinds]

Something to think about: If you toss a tennis ball at a first floor window and then at a second floor window, what factors go into how loud the resulting sound would be inside the two rooms?

 

[sophiecentaur]

Is this a 1. A homework question or 2. Prelude to a legal case?
What do you already know about sound propagation in air and in solids?
PS are there any other large buildings nearby?

 

[williamcarter]

Something to think about: If you toss a tennis ball at a first floor window and then at a second floor window, what factors go into how loud the resulting sound would be inside the two rooms?

The pressure/ force aplied, impedance I guess?

 

[williamcarter]

Is this a 1. A homework question or 2. Prelude to a legal case?
What do you already know about sound propagation in air and in solids?
PS are there any other large buildings nearby?

It is just a thinking question I asked myself, no building nearby. I would have assumed that at 2nd floor the sound/noise should be less than at 1st floor. I thought as height increases(this case by 4 m) the sound usually propagates in the solid and it is reflected back, so it will take longer to propagate to greater heights/altitudes?

 

[phinds]

The pressure/ force aplied, impedance I guess?

I mean SPECIFICALLY. What is the action of the ball on each window? Hint: think about the normal force.

 

[williamcarter]

I mean SPECIFICALLY. What is the action of the ball on each window? Hint: think about the normal force.

I can think just about the pressure that is applied on the window, to hit the 2nd floor it would require more force in order to reach

 

[sophiecentaur]

I mean SPECIFICALLY. What is the action of the ball on each window? Hint: think about the normal force.

Where is this going? Are you comparing 'mgh' energy loss with 1/r²loss?
I am a bit confused by the OP. Are we being asked to help predict something or will he come up with an situation that is producing louder noise on floor 2 than on floor 1? It seems such a no-brainer to say the lower floor will get more via any route / mechanism that there has to be an evil catch to bring us crashing to the ground.

 

[williamcarter]

Where is this going? Are you comparing 'mgh' energy loss with 1/r²loss?
I am a bit confused by the OP. Are we being asked to help predict something or will he come up with an situation that is producing louder noise on floor 2 than on floor 1? It seems such a no-brainer to say the lower floor will get more via any route / mechanism that there has to be an evil catch to bring us crashing to the ground.

My question was , given that we have a building in open air , isolated everywhere same , and an outside noise occurring, where will the noise have the biggest impact
a) 1st floor
b)2nd floor which is 4 m above 1st floor
c) it won t be any difference in noise

 

[phinds]

My question was , given that we have a building in open air , isolated everywhere same , and an outside noise occurring, where will the noise have the biggest impact
a) 1st floor
b)2nd floor which is 4 m above 1st floor
c) it won t be any difference in noise

and what do you think and why?

 

[sophiecentaur]

, and an outside noise occurring,

That's very relevant. The distance of the source from the building would / could be relevant and also the temperature profile of the air around the building could have an effect. You can get refraction of sounds through air just as you can get it with light, although just 4m is not far.
I second phinds and would be interested to know what your ideas are about the subject.

 

[williamcarter]

and what do you think and why?

It won't be any difference in noise between the 2 floors/levels right?

 

[williamcarter]

That's very relevant. The distance of the source from the building would / could be relevant and also the temperature profile of the air around the building could have an effect. You can get refraction of sounds through air just as you can get it with light, although just 4m is not far.
I second phinds and would be interested to know what your ideas are about the subject.

The distance from the building let's say about 3-4 meters , temperature constant at like 20 degrees Celsius, building not surrounded by anything, but has same phonic isolation everywhere.

I think that there won't be any difference in noise between the 2 floors, so if someone is having a party on the ground floor, the 1st and 2nd floors will hear the same noise(no difference in the noise intensity between the 2 floors that are 4 m apart in height.)

 

[sophiecentaur]

The distance from the building let's say about 3-4 meters

That is very close. Where is it positioned vertically? You need to specify the problem much more tightly if you expect to get an answer.

if someone is having a party on the ground floor, the 1st and 2nd floors will hear the same noise

That is a very unlikely thing to happen. What about the fact that the sound has to travel through the thickness of two floors, as opposed to one thickness of floor? You need to think again about what's actually happening. Why not read a bit about techniques for sound proofing buildings? Google is full of links. It's only necessary to read one or two to find something appropriate for your level.

 

[williamcarter]

That is very close. Where is it positioned vertically? You need to specify the problem much more tightly if you expect to get an answer.

That is a very unlikely thing to happen. What about the fact that the sound has to travel through the thickness of two floors, as opposed to one thickness of floor? You need to think again about what's actually happening. Why not read a bit about techniques for sound proofing buildings? Google is full of links. It's only necessary to read one or two to find something appropriate for your level.

Thanks for the quick reply.

That is very close. Where is it positioned vertically? You need to specify the problem much more tightly if you expect to get an answer.

Say about a distance of 10-12meters away from the building

That is a very unlikely thing to happen. What about the fact that the sound has to travel through the thickness of two floors, as opposed to one thickness of floor? You need to think again about what's actually happening. Why not read a bit about techniques for sound proofing buildings? Google is full of links. It's only necessary to read one or two to find something appropriate for your level.

Now you confused me, so you are saying the people on the first floor will be more affected than those on the 2nd floor?
I just want a detailed answer: If someone is having a party on the ground floor 10 meters away from the building, is it true that the people on 2nd floor will be less affected due to the greater thickness that the sound needs to go through?(2 levels of thickness) compared with 1?

How is it correct with regards to the noise(1st floor vs 2nd floor) ? What is the correct answer and why?

 

[davenn]

I think that there won't be any difference in noise between the 2 floors, so if someone is having a party on the ground floor, the 1st and 2nd floors will hear the same noise(no difference in the noise intensity between the 2 floors that are 4 m apart in height.)

that's incorrect the more floors/ceilings the sound travels through the more attenuated the sound will get
anyway, that is a different issue compared to an outside sound
Ignoring minor air pressure/temperature differences with height, and the building insulating being constant, there is
only one that that will affect the sound level ( assuming an Omni-direction sound source)

have you figured out what that is yet ?

 

[williamcarter]

that's incorrect the more floors/ceilings the sound travels through the more attenuated the sound will get
anyway, that is a different issue compared to an outside sound
Ignoring minor air pressure/temperature differences with height, and the building insulating being constant, there is
only one that that will affect the sound level ( assuming an Omni-direction sound source)

have you figured out what that is yet ?

The sound was coming from the exterior not from the interior, was coming from outside the building, how will this affect the noise with regards to the 1st and 2nd floor? Will be there any difference?

 

[davenn]

The sound was coming from the exterior not from the interior, was coming from outside the building, how will this affect the noise between the 1st and 2nd floor? Will be there any difference?

as I said, yes there will and assuming the things that I stated ... what is the only thing left that will affect the sound level at each location ?

 

[williamcarter]

as I said, yes there will and assuming the things that I stated ... what is the only thing left that will affect the sound level at each location ?

So the sound comes from outside the building, and it will get atenuated until it reaches 2nd floor right, I mean the people inside the building on the 2nd floor will hear less noise than those on the 1st floor right?But how exactly, and why? There are 4 meters between the 2 floors.

I can think just about temperature/pressure difference between the 2 floors, and obviously the height.

 

[davenn]

I can think just about temperature/pressure difference between the 2 floors,

as I said, the temp/press differences over that height are minor and not worth worrying about

what factor specifically does height play in it
if it is higher it is ___________ from the source, therefore the sound is more ___________

you fill in the blanks

 

[williamcarter]

as I said, the temp/press differences over that height are minor and not worth worrying about

what factor specifically does height play in it
if it is higher it is ___________ from the source, therefore the sound is more ___________

you fill in the blanks

If it is higher is has a greater distance from the source, therefore the sound/noise is less.

But is it such a big difference given that there is 4m between the 2 floors?

When I said there will be less noise on 2nd floor , SophieCentaur laughed at me on post #8

 

[davenn]

If it is higher is has a greater distance from the source, therefore the sound/noise is less.

YES and it is more attenuated

But is it such a big difference given that there is 4m between the 2 floors?

naaa, by ear probably not noticeable ... but may be measured with sensitive sound meter

if you were to compare over a much further distance ... 10, 20 floors or more then you would start hearing a signif difference

 

[williamcarter]

YES
naaa, by ear probably not noticeable ... but may be measured with sensitive sound meter

if you were to compare over a much further distance ... 10, 20 floors or more then you would start hearing a signif difference

Where is this going? Are you comparing 'mgh' energy loss with 1/r2loss?
I am a bit confused by the OP. Are we being asked to help predict something or will he come up with an situation that is producing louder noise on floor 2 than on floor 1? It seems such a no-brainer to say the lower floor will get more via any route / mechanism that there has to be an evil catch to bring us crashing to the ground.

What about this?

 

[davenn]

What about this?

Where is this going? Are you comparing 'mgh' energy loss with 1/r2loss?
I am a bit confused by the OP. Are we being asked to help predict something or will he come up with an situation that is producing louder noise on floor 2 than on floor 1? It seems such a no-brainer to say the lower floor will get more via any route / mechanism that there has to be an evil catch to bring us crashing to the ground.

that wasn't me ... I really don't know what he was getting at ? don't worry about it

the bolded bit was the important part, for the reason you have now discovered Dave

 

[williamcarter]

that wasn't me ... I really don't know what he was getting at ? don't worry about it

the bolded bit was the important part, for the reason you have now discovered Dave

Thank you.

 

[phinds]

@williamcarter I already GAVE you the solution by asking the question that I did I post #6. You have not answered it. We don't spoon-feed answer here we try to help people figure out how to GET answers themselves.

 

[davenn]

@williamcarter I already GAVE you the solution by asking the question that I did I post #6. You have not answered it. We don't spoon-feed answer here we try to help people figure out how to GET answers themselves.

As with Sophi, I was a wondering where that was going ... it may have confused William

Anyway, I gave hints that led him through to thinking it out for himself
took a little longer but got there in the end

 

[phinds]

As with Sophi, I was a wondering where that was going ... it may have confused William

Anyway, I gave hints that led him through to thinking it out for himself
took a little longer but got there in the end

I think both you and he are still overlooking the point of my question about the normal force.

 

[sophiecentaur]

as I said, the temp/press differences over that height are minor and not worth worrying about

Can you be sure of that? The temperature near the ground can be several degrees higher than at a few metres (hot ground after a day's sun). That could have the effect of tilting the waves upwards. This would only apply significantly for a distant sound source.
However, if the sound source is in the middle distance that is proposed by the OP, we are in the most difficult situation for any rough calculation.
The OP can easily draw a diagram with the distances he has specified and (Pythagoras) work out the difference in distances to the two floors. Using the inverse square law (crude, I know) he can work out the relative 'spreading loss' from source to the two windows. This effect will be less and less as the source moves away.

I just want a detailed answer:

To get a detailed answer, you need a detailed specification of the situation, which you haven't supplied. Can we reduce the problem to the sound against two windows at different levels? If the sound source is outside, then there won't be much sound transmitted through the floors.