[JGH1]

I believe I have an easier fix for this problem rather than looking at "snow" -

Audacity can do the job easily (free program...go to audacity.sourceforge.net). Open the file, highlight a section and go to the "analyze" pull-down menu, and select "Plot Spectrum". A window plotting the frequency response will pop up. If the file is mp3 sourced, it will have nothing above approx. 15kHz. If there IS frequency response plotted above that point, it's not an mp3.

John