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MSheldon

The Loudest Sound in the World

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I did some work with Orbital ATK that is building the new rockets for NASA and it is even louder than the Saturn V rocket. 

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The loudest sound (SPL) in the air is equal to 1 ATM at sea level

1ATM=101325N/m2 ---- 20x log(101325/0,00002)= 194dB SPL (Sound Pressure) (Propagation thru the air)

Sound pressures over 1ATM are truncated.

The Nasa article talks about Power (The power of the source) http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120003777.pdf

The article mix sound pressure and sound power. :mellow: 

 

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  Wow awesome read thanks!!  Mr. Ramallo - that is some crazy numbers thing you've got going on there.  Care to explain?  What the hell is an ATM?!  Why would over 1 ATM be truncated?  This thread went way over my head!

  Dan Izen

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The article mix sound pressure and sound power. :mellow: 


I can't open the article at the moment anymore, but I remember from reading it a while ago, that the article did use both sound pressure and sound power, but they didn't mix it. They explained the different usages in the first chapter. IIRC sound power referred to sound directly at the rocket, and sound pressure referred to sound further away.
Of course, this discussion would be a lot easier if the article were still there.

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Mix pressure and power on the graphics (For example the rocket dB is power not SPL)

 

7 hours ago, Izen Ears said:

  Wow awesome read thanks!!  Mr. Ramallo - that is some crazy numbers thing you've got going on there.  Care to explain?  What the hell is an ATM?!  Why would over 1 ATM be truncated?  This thread went way over my head!

  Dan Izen

ATM is Atmospheric pressure, at sea level 1ATM is the pressure (It depends)

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Mix pressure and power on the graphics (For example the rocket dB is power not SPL)

Yes, but that's exactly what I said. They do not mix those two terms indiscriminately. In the paragraph labelled "Overview" they explain why they sometimes use "sound power" (the acoustic power at the engine) and "sound pressure" (propagation of acoustic energy).
What is wrong with this? Or where did they get this wrong?

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The sound power are inherent to the source (Always is the same not depends of the distance for example), but this power have the need of a medium for propagation (F.E. air). IMMO The "loudest sound" is always related to "pressure"

The loudest sound (Pressure) in air is 194dB SPL peak at sea level (1ATM)

Apples with apples and oranges with oranges. IMMO Is wrong mix both, and is easy get a estimated pressure from power (uninformed redactor?)

You can see a right table on the Wiki (oranges with oranges)

https://en.wikipedia.org/wiki/Sound_pressure

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Apples with apples and oranges with oranges. IMMO Is wrong mix both, and is easy get a estimated pressure from power (uninformed redactor?)

Well, that may be your opinion, but it's not the opinion of the scientists at NASA.
It's not an uninformed redactor, rather - again - they do explain why and when they use power and pressure and then they use both in this article (and elsewhere on the NASA site), but they use each term in its right place as defined in the article.

Here is another orange for you

https://en.m.wikipedia.org/wiki/Sound_power

(Although that article is not very well written)

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On 11 de agosto de 2016 at 7:39 PM, Constantin said:


Well, that may be your opinion, but it's not the opinion of the scientists at NASA.
It's not an uninformed redactor, rather - again - they do explain why and when they use power and pressure and then they use both in this article (and elsewhere on the NASA site), but they use each term in its right place as defined in the article.

Here is another orange for you

https://en.m.wikipedia.org/wiki/Sound_power

(Although that article is not very well written)

I said "uninformed redactor", is my opinion, sorry.

Isn't possible mix Sound Pressure and Sound Power in this table (In the same axis)

Thank you for the wiki page (is the same as I wrote), I recommend you read carefully as well https://en.wikipedia.org/wiki/Sound_pressure

Thank you!

 

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Nice article. They point out human hearing is 64-23k Hz. Have I been living a lie of 20-20k?

The pistol shrimp is the loudest animal in the world.  It snaps its claw to stun its prey; hitting up to 200dB! I'm assuming underwater sounds would be weighted differently than sounds propagating in our air due to the fact it's harder to hit high dB ratings in a gas.

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