Theoretical limit for loud music??

[martin griffith]

from a post in rec.audio pro.


NEW YORK (Reuters Health) - Blasting music can be hard on the ears and
the neighbors, and now researchers say it can also pack enough punch
to
collapse a lung.

Reporting in the medical journal Thorax, they describe the cases of
four
young men who suffered a lung collapse -- technically called
pneumothorax --that appeared to be triggered by loud music. Three of
the
men were at a concert or club when the pneumothorax occurred, while
the
fourth was in his car, which was outfitted with a 1,000-watt bass box
because he "liked to listen to loud music."

http://tinyurl.com/5hcyy




martin

Serious error.
All shortcuts have disappeared.
Screen. Mind. Both are blank.

 

[Tony]

from a post in rec.audio pro.

NEW YORK (Reuters Health) - Blasting music can be hard on the ears and
the neighbors, and now researchers say it can also pack enough punch
to
collapse a lung.

Reporting in the medical journal Thorax, they describe the cases of
four
young men who suffered a lung collapse -- technically called
pneumothorax --that appeared to be triggered by loud music. Three of
the
men were at a concert or club when the pneumothorax occurred, while
the
fourth was in his car, which was outfitted with a 1,000-watt bass box
because he "liked to listen to loud music."

http://tinyurl.com/5hcyy

martin

Serious error.
All shortcuts have disappeared.
Screen. Mind. Both are blank.

.... none of which would however come even close to the "theoretical
limit for loud music" (which is when the peak negative pressure gets
down to a perfect vacuum - somewhere around 180dB SPL if memory
serves).
Tony (remove the "_" to reply by email)

 

[martin griffith]

On Fri, 03 Sep 2004 13:53:53 +0200, martin griffith
snip dubious stuff

... none of which would however come even close to the "theoretical
limit for loud music" (which is when the peak negative pressure gets
down to a perfect vacuum - somewhere around 180dB SPL if memory
serves).
Tony (remove the "_" to reply by email)

I know I should have said Human limit.....
Imagine 20Hz sine wave that goes from a vacuum to 2 atmos. More like a
hurricane than music.

But I dont think you could actaully hear the negative bottom part of
the cycle, since sound doesn't travel through a vacuum!


martin

Serious error.
All shortcuts have disappeared.
Screen. Mind. Both are blank.

 

[Rolavine]

Subject: Re: Theoretical limit for loud music??

From: martin griffith [email protected]
Date: 9/3/2004 7:15 AM Pacific Daylight Time
Message-id: <[email protected]>



I know I should have said Human limit.....
Imagine 20Hz sine wave that goes from a vacuum to 2 atmos. More like a
hurricane than music.

But I dont think you could actaully hear the negative bottom part of
the cycle, since sound doesn't travel through a vacuum!

Nice thought, so if you were in a pressurized chamber you could get louder. I
can see it now, car pressurization systems for louder music. Seeing bugged eyed
teenagers clawing at the windows and looking desperate.

I'm working on a new super sub woofer that uses a patented switchable
containment field around a quantum black hole for Bass you can really feel. If
we can only stop it from digesting the suburban kids and the new Honda Civic
their rich parents bought them. Oh well, small loss.

Rocky

 

[John Larkin]

... none of which would however come even close to the "theoretical
limit for loud music" (which is when the peak negative pressure gets
down to a perfect vacuum - somewhere around 180dB SPL if memory
serves).

There's no limit on the positive-direction overpressure, if you don't
mind a bit of harmonic distortion (and who would, when you're being
homogenized to death.)

John

 

[Frank Miles]

... none of which would however come even close to the "theoretical
limit for loud music" (which is when the peak negative pressure gets
down to a perfect vacuum - somewhere around 180dB SPL if memory
serves).
Tony (remove the "_" to reply by email)

Of course, it takes a _lot_ of energy to create extremely loud sound.
There was once a study of how loud sound affects various ear structures;
to get adequate sound levels, some experimental animals (think it was
in rats) were anaesthatized in cages in close proximity to the space shuttle
rocket boosters. IIRC the sound of the boosters when they were later
fired was still below the 180dB mentioned in another posting. {Even
that was not enough -- at least in those animals -- to collapse lungs.}

-frank
--

 

[Kevin Aylward]

There's no limit on the positive-direction overpressure, if you don't
mind a bit of harmonic distortion (and who would, when you're being
homogenized to death.)

Technical point. Actually, there is a maximum pressure. High pressure
means high velocity, and this is limited, to yes.. the speed of light.

Kevin Aylward
[email protected]
http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

 

[John Larkin]

Technical point. Actually, there is a maximum pressure. High pressure
means high velocity, and this is limited, to yes.. the speed of light.

Oh, how could I have been so wrong!

John

(hangs head in shame)

 

[John Woodgate]

... none of which would however come even close to the "theoretical
limit for loud music" (which is when the peak negative pressure gets
down to a perfect vacuum - somewhere around 180dB SPL if memory
serves).

194 dB SPL, if the air pressure is 1 bar.

 

[John Woodgate]

I read in sci.electronics.design that Frank Miles <[email protected]>

{Even that was not enough -- at least in those animals -- to collapse
lungs.}

No, it isn't. What happens, as explained in the original article, is
that a small weakness in the lung wall ruptures under the intense sound
pressure and allows air into the chest cavity. It is this air that
causes the lung to collapse, if untreated for long enough (e.g. 30
minutes).

 

[Guy Macon]

John Larkin says...

Oh, how could I have been so wrong!

John

(hangs head in shame)

I am not sure that you were wrong. SPL is a function of the
velocity and the mass of the medium. Unlike the negative limit
which is hard clipping at zero pressure (vacuum), approaching
the positive limit is a matter of pouring more and more energy
into attempting to accelerate the medium, only to have that
energy turn into mass rather than velocity at the E=MC2 rate.
This additional mass allows higher pressures, and can approach
infinity if you pump enough energy in.

 

[John Larkin]

John Larkin says...


I am not sure that you were wrong. SPL is a function of the
velocity and the mass of the medium. Unlike the negative limit
which is hard clipping at zero pressure (vacuum), approaching
the positive limit is a matter of pouring more and more energy
into attempting to accelerate the medium, only to have that
energy turn into mass rather than velocity at the E=MC2 rate.
This additional mass allows higher pressures, and can approach
infinity if you pump enough energy in.

Good point. I wonder what's the SPL close to one of those exploding
supernovas.

John

 

[Guy Macon]

Good point. I wonder what's the SPL close to one of those exploding
supernovas.

I can think of someone who I would like to send there with a Radio
Shack SPL meter...

 

[Tony]

194 dB SPL, if the air pressure is 1 bar.

1800dB? what was I thinking? I always end up regretting it when I
quote "hearsay" without working it out for myself! But now, having
done that I feel I ought to point out that 0dB SPL is defined as 20uPa
RMS (not peak), which means clipping starts around 191dB SPL at 1 bar.

Tony (remove the "_" to reply by email)

 

[John Woodgate]

But now, having done that I
feel I ought to point out that 0dB SPL is defined as 20uPa RMS (not
peak), which means clipping starts around 191dB SPL at 1 bar.

Don't feel in any way compelled to. (;-)

Yes, you are quite right. Or would be if air were a perfect gas. We
could go on like this, getting more and more refined, for no practical
advantage.

 

[Kevin Aylward]

John Larkin says...


I am not sure that you were wrong.
SPL is a function of the
velocity and the mass of the medium.

Yes, but technically its the momentum. Light has pressure, but no "rest
mass".

Unlike the negative limit
which is hard clipping at zero pressure (vacuum), approaching
the positive limit is a matter of pouring more and more energy
into attempting to accelerate the medium, only to have that
energy turn into mass rather than velocity at the E=MC2 rate.
This additional mass allows higher pressures, and can approach
infinity if you pump enough energy in.

That's not quite how it works though. This "mass increase" bit is a bit
of a misnomer. Mass itself, doesn't actually increase. No professional
physicist uses the concept at all, well, accept when writing popular
paperbacks.

Shit, now I have to go and think about when what gets applied to what,
certainly this pops up (quick search) as an example:

http://www.as.utexas.edu/astronomy/education/spring01/lambert/classnotes16.html
"The Heisenberg Uncertainty Principle also contains the seeds to setting
a limit on how massive a white dwarf can be. Remember, nothing goes
faster than light, so the maximum momentum of an electron is set by the
speed of light and so there is a maximum pressure provided by degenerate
electrons. This maximum sets the maximum mass that a white dwarf may
have"

This is one of those things that cropped up in class, now with the
qualifiers forgotten. I'll have to do some more investigations as to
when the limit applies...

Kevin Aylward
[email protected]
http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

 

[Robert Baer]

... none of which would however come even close to the "theoretical
limit for loud music" (which is when the peak negative pressure gets
down to a perfect vacuum - somewhere around 180dB SPL if memory
serves).
Tony (remove the "_" to reply by email)

And do not forget the compression of an H-bomb...

 

[Guy Macon]

Guy Macon wrote:

Yes, but technically its the momentum. Light has pressure, but no "rest
mass".

I thought we were talking about air approaching lightspeed.

That's not quite how it works though. This "mass increase" bit is a bit
of a misnomer. Mass itself, doesn't actually increase. No professional
physicist uses the concept at all, well, accept when writing popular
paperbacks.

News to me - but then again, I am an eclectronicsite, not a Physicsoid...

http://www.google.com/search?q=physics++"mass+increases"

 

[Mark Fergerson]

(in <[email protected]>) about 'Theoretical
limit for loud music??', on Sat, 4 Sep 2004:




Don't feel in any way compelled to. (;-)

Yes, you are quite right. Or would be if air were a perfect gas. We
could go on like this, getting more and more refined, for no practical
advantage.

"No practical advantage"? What better than to set the bar for
Audiophools, in hopes they'll try to reach it?

Mark L. Fergerson

 

[Kevin Aylward]

I thought we were talking about air approaching lightspeed.


News to me - but then again, I am an eclectronicsite, not a
Physicsoid...

http://www.google.com/search?q=physics++"mass+increases"

Sure, you'll find many references to "mass increase", but this is
"inertial mass", a somewhat outdated term that is not very useful for
serious work. For example, one gets into the bother of longitudinal mass
and transverse mass, which are different. Mass is an invariant in
Relativity.

have a look at
http://math.ucr.edu/home/baez/physics/Relativity/SR/mass.html

or maybe http://www.anasoft.co.uk/physics/gr/index.html

Kevin Aylward
[email protected]
http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.