Re: calculate dB from PCM WAV file

["Steve" pelikan45224]

The samples in the file are from a wave so, even if the amplitude is high, many 
will be values near 0.

You could do something like find the root mean square

sqrt( (1/n) sum( (x_i)^2 ;i=0,n-1))

of consecutive values (1000, say) and then log-transform it.

This worked pretty well for me a while back. I can send you the Java code if 
you like.

Steve P

--- In  lisetserv neck <> 
wrote:
>
> Hi,
> 
> I need to write a program to calculate the dB values from PCM wave files so
> that I could do batch calculations for analysis. Could anyone help me how to
> convert the raw sample values stored in WAV files to the dB(FS) values we
> see on the meter of sound softwares such as Audacity? Taking log directly
> does not seem to match... Thanks a lot for the help.
> 
> Po-Jen
> 
> 
>