John, in your help file it tells you how to get a flat response from the sound card. I unchecked the C-weighting box and got rid of the cal file and then remeasured and the graph looked exactly the same.
According to the help file, once you do this the graph should be ruler flat. So I just want to know that I'm doing this right.
I did as you suggested and pressed the measure button. Graph looks like this :
--Regards,