linuxaudio.org

Arnold Krille wrote:

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> Hi Paul and all (that rhymes :-),

>

> 2007/2/27, Paul Winkler :

>> On Tue, Feb 27, 2007 at 10:40:46PM +0100, Arnold Krille wrote:

>> > 120dB is the difference between just loud enough to be heard by your

>> > ear (1dB) and the loudness when the bones in your ear bow to protect

>> > it. At higher levels (>120dB) your ear aches but it will recover if

>> > the noise isn't permanent. At least thats the definition I learned...

>> I got my numbers from http://en.wikipedia.org/wiki/Decibel#Safety but

>> obviously their numbers represent some sort of typical examples; I

>> been in a number of discotheques (here in the US we can't pronounce

>> that so we just say "clubs") that had sound levels far above 100 dB.

>> The amount of time the ear can be exposed to a given sound pressure

>> level before sustaining permanent damange clearly varies a lot from

>> person to person. But government standards are probably a good

>> guideline to start with, eg. OSHA table G-16:

>> http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&...

>>

>

> I stand corrected, my numbers where from my physics-book which states

> that 120dB is the "Schmerzgrenze" and 0dB is the slightest whisper

> human ear can hear. Problem is that these values vary on the frequency

> so there is a correction curve standardised(?)

  Fletcher-Munson did the first (I believe) curves:

(http://en.wikipedia.org/wiki/Fletcher-Munson_curve
Others have refined.
see more: http://en.wikipedia.org/wiki/Equal-loudness_contours
> in some A-something

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> paper so these corrected values for the human ear are called db(A)...

Yeah... dB doesn't mean a whole lot unless there is a reference.

see also: http://en.wikipedia.org/wiki/A-weighting
The OSHA standards _are_ important, so it's good that you listed them.
--

brad fuller

  http://www.Sonaural.com/

  +1 (408) 799-6124