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Author Topic: Is There An Upper Limit To How Loud Something Can be ?  (Read 11171 times)

Offline neilep

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Dearest Friday Viewers Of this Kweschun !

Shouldn't ewe be out having fun and "larging it" Friday style ?......Nope ewe shouldn't !...ewe need be right here reading this kweschun and providing an answer !....Shame on ewe for even thinking about my earlier suggestion !

See BRian ATlas here  ?


Brian Listening To Something Loud *actually he's been forced
to endure an endless loop of the ' birdy song ' non stop for the last
15 hours !...lucky him eh ?


My question is all about loudness !...what's the loudest thing ever ?...when wifey does a bottom burp believe me that has got to be pretty close to the loudest thing ever ...(certainly the smelliest  :o.....I mean Counties run away !!)

If one could measure the loudness of a supernova (assuming not in a vacuum) how loud would that be ?...no need to get all semantic on me...just your bog standard supernova will do ta.....and...well..is there a threshold to loudness ?

This has got me thinking...I imagine black holes which are like ,well big, must be the quietest things ever yes ?..cos if light can't escape I expect sound can't either eh ?..making them the ideal place to have a library !


whajafink ?

hugs and shmsihes

mwah mwah mwah



Neil
Shhh !!..I'm Trying To Study My Black Hole
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
« Last Edit: 14/09/2012 21:04:34 by neilep »


 

Offline FuzzyUK

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Re: Is There An Upper Limit To How Loud Something Can be ?
« Reply #1 on: 15/09/2012 12:17:42 »
My question is all about loudness !...what's the loudest thing ever ?...when wifey does a bottom burp believe me that has got to be pretty close to the loudest thing ever ...

Apparently if you fart at the same time as her and in the correct phase you could add a few dB to the total sum of audio output (please don't try this after eating curry). So whatever you think is the loudest sound around, you could make it sound louder.
 

Offline RD

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Re: Is There An Upper Limit To How Loud Something Can be ?
« Reply #2 on: 15/09/2012 13:37:06 »
The properties of  medium the sound is travelling in could create an upper limit ...
e.g. sound waves compress air. The louder the sound the greater the compression.  If air is compressed sufficiently it will change from gas to liquid.
« Last Edit: 15/09/2012 13:40:30 by RD »
 

Offline neilep

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Re: Is There An Upper Limit To How Loud Something Can be ?
« Reply #3 on: 15/09/2012 16:23:14 »
My question is all about loudness !...what's the loudest thing ever ?...when wifey does a bottom burp believe me that has got to be pretty close to the loudest thing ever ...

Apparently if you fart at the same time as her and in the correct phase you could add a few dB to the total sum of audio output (please don't try this after eating curry). So whatever you think is the loudest sound around, you could make it sound louder.

Gosh !!..Thanks FuzzyUK......this is really some empirical study I am very keen to indulge in..... ;D
 

Offline David Cooper

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Re: Is There An Upper Limit To How Loud Something Can be ?
« Reply #4 on: 15/09/2012 21:05:09 »
The properties of  medium the sound is travelling in could create an upper limit ...
e.g. sound waves compress air. The louder the sound the greater the compression.  If air is compressed sufficiently it will change from gas to liquid.

Is that what happens with supersonic jets where you get funnels of vapour forming round them? A sonic boom can be heard for some distance, but when Krakatao (popularly known as Krakatoa due to a typo) blew, it was heard thousands of miles away, so it would be interesting to know how much it must have compressed the air at the scene.

Whatever the case though, sound can still travel through a liquid, so I can't see that there's going to be any limit on how loud a sound can be until things get so compressed that you create a black hole.
 

Offline evan_au

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Re: Is There An Upper Limit To How Loud Something Can be ?
« Reply #5 on: 16/09/2012 06:41:33 »
I think that you are right that a Supernova has to be about the loudest single event possible.
The equivalent energy of a whole galaxy, turned into the violent movement of subatomic particles - pretty loud. Sometimes this relativistic debris runs into shells of gas from previous planetary nebulae, and lights them up too...

A starquake on a a neutron star must release an enormous amount of energy, and a medium made up of neutronium should be able to propagate that sound very well.

Our sun is continuously bubbling with enormous convection cells (http://en.wikipedia.org/wiki/Granule_%28solar_physics%29), and occasional Coronal Mass Ejections (http://en.wikipedia.org/wiki/Coronal_mass_ejection#Physical_properties) - this must represent the loudest sounds in our Solar system.

Re: Discussions about atomic bomb blasts above - photos & movies of atomic bomb blasts show a transient, rapidly expanding cone of cloud after the explosion - this is probably momentary condensation of atmospheric moisture into clouds as it is hit by shock waves traveling outwards from ground zero. 
 

Offline Bored chemist

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Re: Is There An Upper Limit To How Loud Something Can be ?
« Reply #6 on: 16/09/2012 10:20:43 »
"I think that you are right that a Supernova has to be about the loudest single event possible."
In space, no one can hear you scream.

Sudden compression of gases heats them.
Even at normal temperatures most of the gases in the atmosphere are well above their critical temperatures and cannot be liquefied by pressure alone- you need to cool them.

Sound is made from variations in air pressure. The deviation from the average pressure includes negative deviations.
Since there are compressions and rarefactions you need to consider both.
Adding another atmosphere of  pressure to the normal doesn't alter the behaviour of air very much, but reducing it to zero certainly does.

The problems with loudest sounds don't happen with the peak pressures- they happen with the troughs.
 

Offline evan_au

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Re: Is There An Upper Limit To How Loud Something Can be ?
« Reply #7 on: 16/09/2012 12:13:30 »
According to: http://en.wikipedia.org/wiki/Moment_magnitude_scale#Nuclear_explosions, "one kiloton nuclear explosion creates a seismic signal with a magnitude of approximately 4.0".
http://en.wikipedia.org/wiki/TNT_equivalent#Examples "The 2004 Indian Ocean Earthquake released 9,560 gigatons of TNT (40,000 EJ) equivalent"

The acoustic pressure of earthquakes, atomic bombs and solar granules is mostly at frequencies well below the frequency range of human hearing.   
 

Offline neilep

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Re: Is There An Upper Limit To How Loud Something Can be ?
« Reply #8 on: 16/09/2012 12:36:08 »
The properties of  medium the sound is travelling in could create an upper limit ...
e.g. sound waves compress air. The louder the sound the greater the compression.  If air is compressed sufficiently it will change from gas to liquid.


hmmmmm.....as Spock would say "InterAIRsting" ...ewe've inspired this kweschun..thanks RD
 

Offline neilep

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Re: Is There An Upper Limit To How Loud Something Can be ?
« Reply #9 on: 17/09/2012 10:26:12 »
Thank you David, BC and Evan for your great responses.....They are very much appreciated .
 

Offline wolfekeeper

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Re: Is There An Upper Limit To How Loud Something Can be ?
« Reply #10 on: 17/09/2012 19:58:37 »
I can't believe you missed the obvious joke/truth:

The big bang was the loudest eva!

If you're talking sound waves though, at sea level, IRC you can't go above about 192 dBA, since above that, the low pressure bit of the wave hits vacuum, and you can't go below that, so it becomes a shock wave which is no longer sound in the normal sense. I don't think there's any realistic upper limit to shock wave pressures.
« Last Edit: 17/09/2012 20:00:12 by wolfekeeper »
 

Offline chris

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Re: Is There An Upper Limit To How Loud Something Can be ?
« Reply #11 on: 17/09/2012 22:31:08 »
192 dB - that's nearly as loud as the Who!
 

Offline wolfekeeper

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Re: Is There An Upper Limit To How Loud Something Can be ?
« Reply #12 on: 17/09/2012 23:16:13 »
Good job the Who weren't playing underwater, at the bottom of the Mariana Trench, the pressure is so high they could have turned it up to 12!
 

Offline damocles

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Re: Is There An Upper Limit To How Loud Something Can be ?
« Reply #13 on: 26/09/2012 13:53:24 »
Sound is a longitudinal wave, meaning a periodic variation in pressure along the direction of propagation. The way I would see it is that sound levels can only increase until you get an amplitude where the waves are overlapping with one another. What you have at that point is not a sound, but a shock. So I would expect that a sound does reach a maximum level where it remains a sound -- dependent on the material of propagation. If the "sound" exceeds this critical level, it becomes a shock wave rather than a sound wave, and it is characterized by the energy density in the shock front rather than the wave intensity. And shock waves have energy densities that can increase without limit, but not without having drastic effects on the material of propagation.

But I am not well versed in acoustics. How does that picture fit with the way that an acoustics/fluid dynamics expert would see it?
 

Offline wolfekeeper

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Re: Is There An Upper Limit To How Loud Something Can be ?
« Reply #14 on: 26/09/2012 14:27:18 »
I believe you're confusing amplitude and wavelength.
 

Offline damocles

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Re: Is There An Upper Limit To How Loud Something Can be ?
« Reply #15 on: 26/09/2012 14:39:53 »
I believe you're confusing amplitude and wavelength.

nope -- what i am saying is that if amplitude -- which is a vector in the same direction for a longitudinal wave -- exceeds 0.5 * wavelength, then the "sound wave" will becoe a "shock wave"
 

Offline wolfekeeper

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Re: Is There An Upper Limit To How Loud Something Can be ?
« Reply #16 on: 26/09/2012 14:44:39 »
No, sound waves are scalar pressure waves, their amplitude is a pressure.
 

Offline damocles

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Re: Is There An Upper Limit To How Loud Something Can be ?
« Reply #17 on: 26/09/2012 14:52:59 »
No, sound waves are scalar pressure waves, their amplitude is a pressure.

At a microscopic level they can also be seen as amplitude of motion of molecules, particularly in condensed phase propagation media
 

Offline wolfekeeper

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Re: Is There An Upper Limit To How Loud Something Can be ?
« Reply #18 on: 26/09/2012 17:38:42 »
Yes, but the wavelengths of that movement is independent of the amplitude, only the speeds of the molecules change as you increase the amplitude.
 

Offline damocles

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Re: Is There An Upper Limit To How Loud Something Can be ?
« Reply #19 on: 26/09/2012 19:22:48 »
Yes, but the wavelengths of that movement is independent of the amplitude, only the speeds of the molecules change as you increase the amplitude.

not only the speeds, also the extent of their motion.

Pressure waves in a solid:

                                                                                 small amplitude

                                                                                  larger amplitude

                   o                                          o                            shock fronts

I see now though, that although amplitude in terms of peak pressure is monotonic with amplitude in terms of displacement of oscillatory motion, the former can range upward without limit, the latter is limited by interatomic spacing in the original crystal. So the peak pressure/oscillatory limit of displacement relationship is an asymptotic one.
 

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Re: Is There An Upper Limit To How Loud Something Can be ?
« Reply #19 on: 26/09/2012 19:22:48 »

 

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