This page has a more clear display of the formula, to me at least,  
plus a little calculator for it.

http://www.diracdelta.co.uk/science/source/a/w/aweighting/source.html

Now, if you "View Source" of that page, you'll see a setup for an  
array, and if you seek various .js within the page and set that as  
the root of the URL, then you get

http://www.diracdelta.co.uk/science/source/a/w/aweighting/multicalc.js

...which has the formula in Java at least. Perhaps a look at such  
would be enlightening.


Robert

On Sep 12, 2010, at 6:49 PM, Edwards, Waverly wrote:

>
> For more than two weeks I have been trying to understand how to  
> implement an A-Weighted filter for psychology experiments.   
> Currently I have developed a program that will calculate an  
> unweighted average of an audio file, with and without silence.   
> Silence is defined as a decibel value of 44db or less in a .05  
> second window.  Its been a very frustrating two weeks.  I've come  
> across other sites that explain A-Weighting but I have not figured  
> out how the digital filter is implemented.
>
> http://www.beis.de/Elektronik/AudioMeasure/WeightingFilters.html#A- 
> Weighting
> http://www.ptpart.co.uk/show.php?contentid=70#FrequencyWeighting
> http://en.wikipedia.org/wiki/A-weighting
>
> Does anyone understand this and mind giving me direction on how to  
> implement an A-Weighted filter.
>
> Thank you kindly,
>
>
> W.
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