Naked Science Forum
General Science => General Science => Topic started by: neilep on 02/05/2008 15:11:56
-
Dear People Who Know About Sound ?
See Mr Tarquin Potteringintheshed ?
[ Invalid Attachment ]
He's just invented ' Sound '...before he came along nobody knew about sound. Since he invented it, it's become very popular and is certainly my all time favourite thing to listen to.
Is there a minimum and maximum range to the loudness and softness of sound ?
Light has speed limit yes ?..so is there a sound limit.....?..does a single moving atom make a sound ?.....how loud can loud get ?
thank you
Enjoy sound.
Neil
Sound Enquirer
xxxxxxxxxx
-
Then quietest sound you can hear (average person) is 0dB (by definition). 100dB is very, very loud, and corresponds to 10000000000 times the power (that is ten to the power ten). The way that loudness is measured is on a 'log scale' because you hear and increase of , say, ten times, is about the same, whatever level you start with.
One Bel (10 deciBels) corresponds to ten times. Two Bel (20 deciBels) corresponds to a hundred times.
And don't be rude about my Uncle. He had immaculate dress sense.
-
It is totally dependent on the organism listening. All critters have a specific range of sound that they can hear. For example - bats, dogs, polar bears, rats (they are almost blind) etc., etc.
-
I suspect there is a min and max limit to sound independent of the ability of the listener. At some point the random movements of the air will be significantly greater than the coordinated movements caused by the coherently fluctuating pressure wave. The sound will be lost in the noise. At the top end, I am not sure, but suspect that with a sufficiently large pressure wave the Nitrogen could liquify and the sound could not progress. You would need a powerful speaker and amplifier though :-)
-
Not sure that in the transient conditions of sound you can really think of phase changes, such as the liquefaction of nitrogen. On the other hand, on the low pressure phase of a wave, there must come a time when there is not a single atom within the semi-wave, and that point there is no way to reduce the pressure further, so that might be a given maximum sound level (although it would depend on what the average air pressure was, and what the wavelength of the sound you using was).
I think a an interesting question is not merely whether there is a maximum loudness to sound, but whether there is a maximum power to a shock wave? Since a shockwave requires the same high pressure that a sound wave does, if there is no maximum shock wave, then there cannot be a maximum pressure to a sound wave (although it still leaves the minimum pressure, since a shock wave does not require the full pressure cycle that a sound wave requires).
-
Wikipedia claims that 194.0937 decibels is as loud as "undistorted" sound can be at atmospheric pressure. This value will differ at different pressures. Sound waves are composed of two parts: the compression half, and the rarefaction half. At ~194 decibels at atmospheric pressure, the compression half of the wave is double atmospheric pressure and the rarefaction half is a "perfect" vacuum.
http://en.wikipedia.org/wiki/Sound_pressure (http://en.wikipedia.org/wiki/Sound_pressure)