Converting sound level measurements in dbA to db 1

[DHZ]

Does anyone know how to convert a sound level measurement made in dbA to db?<br>
Where: db = 10log(Io/Ir)<br>
dbA = sound measurement based on the 40 phon weighting curve

 

[JoeSmyk]

DHZ-<br>
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You already have a measurement in dB. <br>
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The notation you have denotes a difference in dB from a reference level. The particular reference level is conveyed by the notation: dBA. <br>
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If you were to have an loss in your system, say a curtain that absorbed 30 dB of sound, you could subtract that directly from your source level in dBA to get a received level in dBA. This way, you can create a 'link budget', which accounts for all losses and gains in a system to determine your final signal level. This would still be referenced to the orignial level, in this case the 40 phon weighting curve.<br>
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The 40 phon weighting curve, is a tough one. The exact energy level varies according to the particular frequency measured. It becomes very complex when a variety of time-varying frequencies, such as are found in speech, are measured at the same time. <br>
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Also note that the proper notation is "dB". The "B" refered to is Alexander Graham Bell. Since it is a proper name, it should be capitalized. You may need to turn off the capitalization checker of your spell check (or put up with it), to write good memos.<br>
<br>
-Joe