I How is the damping of sound (over distance) affected by air properties?

[daanisrael]

TL;DR Summary

I want to compare measurement results with theoretical values of a sound measurement. I'm looking for a formula that describes the relation between the humidity of the air, the frequency of the sound and the distance the sound travels.

Hey all,

For my physics major I need to quantify the acoustic effect of sunfields. I'm trying to do this by measuring the sound level before and after a sunfield, and after that by measuring a comparable situation, only without a sunfield. By comparing the results of the two measurements I'll find out what the acoustic effect of the sunfield is, but I have no way of verifying the results.

These are the results:

The Rion graphs are at the backside of the measurement setup, the BK is at the frontside. As you can see, there is clearly a difference in the sound level at the front- and backside of the situation (both with and without the sunfield). This is expected, but I'd like to calculate how much it specifically differs from the theoretical value. This way I can validate the accuracy of my measurement, and also tell a bit more about the hypothesis vs. the outcome.

I'd like a formula that describes the relation between the humidity of the air, the frequency of the sound, the distance between the source and reciever and the attenuation of the sound. I've looked everywhere on internet, even asked my teachers and accompanist, but with no succes. I know there has to be a formula out there, but I can't find one that applies to my situation.

Do any of you know such a formula? Could you maybe help me with it?

Thanks in advance,Daan Israël

 

[sophiecentaur]

@daanisrael hi and welcome to PF.

I haven't heard of "sunfield" and a Google search seemed only to yield commercial names. Can you post a suitable link to explain what it is?
Also, the losses in sound propagation are fairly complicated. If you want to correct for you particular conditions, why not use any data you have and make a look-up table, rather than trying to fit a mathematical formula to your data?

 

[kuruman]

What is a sunfield? I couldn't find that on the internet. In case you haven't seen it, this Wikipedia article provides a good starting point to guide your thinking.

 

[daanisrael]

@daanisrael hi and welcome to PF.

I haven't heard of "sunfield" and a Google search seemed only to yield commercial names. Can you post a suitable link to explain what it is?
Also, the losses in sound propagation are fairly complicated. If you want to correct for you particular conditions, why not use any data you have and make a look-up table, rather than trying to fit a mathematical formula to your data?

What is a sunfield? I couldn't find that on the internet. In case you haven't seen it, this Wikipedia article provides a good starting point to guide your thinking.

Hey,

I'm sorry, I was under the impression that a sunfield was a known concept, but it's not. The correct name is a solarfield, excuse me for my ambiguity.

 

[Baluncore]

The translation of the Dutch "zonneveld" to English as "sun field", may be referring to a PV solar farm, or a solar power generation array?

 

[sophiecentaur]

So where are we now? What is the actual question?

 

[daanisrael]

So where are we now? What is the actual question?

Hey Sophie,

The question is as follows: is there a formula that describes the relation between the attenuation of sound, the distance from the source and the humidity of the air?

note: I've left out the frequency because that will be a problem for another day.

I can understand that it's vague, I hope it's clear this way.

Greetings,

Daan

 

[sophiecentaur]

The question is as follows: is there a formula that describes the relation between the attenuation of sound, the distance from the source and the humidity of the air?

Would https://www.researchgate.net/publication/328383226_ATMOSPHERIC_EFFECTS_ON_SOUND_WAVES_PROPAGATION be of any help?

 

[tech99]

This link might be useful to you. I think the problem is actually very complicated.
https://www.acs.psu.edu/drussell/Demos/Absorption/Absorption.html