- #1

Wes Turner

- 68

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- TL;DR Summary
- How to calculate the reduction in airplane noise as a function of increased distance?

I live close to the (landing) flight path to a major airport. The city has been working with the airport and the FAA to deal with complaints about the noise the jets make as they come in for a landing. I recently attended a meeting where various solutions were discussed, such as changing the flight path or increasing the altitude over residential areas.

I got to wondering how much good that would actually do. I'd like to create a spreadsheet that will calculate the reduction in noise if the plane's altitude is increased from 4,000' to 6,000' or if its overhead path changes from 0.5 miles away from my home to 1.0 miles away.

My foggy memory from my physics classes many years ago tells me that sound decreases as the square of the distance. If the plane is twice as far away, the sound I will hear is 25% (75% less). But I checked a couple of websites and got confusing data. One comfirmed what I thought about the inverse square relationship. Another one said that the sound "pressure" has just an inverse relationship with distance (not the square). I could not figure out what they meant by "pressure".

Finally, one website about decibels said that they are logarithmic. Doubling the distance reduces the sound volume by 6 dB. How much of a reduction is decibels is significant or detectable? And what should the target decibel reading be?

So, how does the sound of an airplane overhead vary with distance? Or is it not that simple?

Thanks

I got to wondering how much good that would actually do. I'd like to create a spreadsheet that will calculate the reduction in noise if the plane's altitude is increased from 4,000' to 6,000' or if its overhead path changes from 0.5 miles away from my home to 1.0 miles away.

My foggy memory from my physics classes many years ago tells me that sound decreases as the square of the distance. If the plane is twice as far away, the sound I will hear is 25% (75% less). But I checked a couple of websites and got confusing data. One comfirmed what I thought about the inverse square relationship. Another one said that the sound "pressure" has just an inverse relationship with distance (not the square). I could not figure out what they meant by "pressure".

Finally, one website about decibels said that they are logarithmic. Doubling the distance reduces the sound volume by 6 dB. How much of a reduction is decibels is significant or detectable? And what should the target decibel reading be?

So, how does the sound of an airplane overhead vary with distance? Or is it not that simple?

Thanks