So in short why this won't work well: Trying to "correct" a highpass filter, you need an inverse filter that has a gain of infinity at DC (since the highpass filter has gain of -infinity at DC). Problem is, -infinity + infinity != zero, so you likely end up with a signal that has increasingly growing DC offset, until you get into clipping.
To fix that, you'd need to put another DC filter on the signal... Eventually you may end up with something that's somewhat better than the original, but certainly not as good as throwing away your soundcard and buying a better DC-coupled sound card that has no capacitor on the input at all, obviating the need for "correcting" it. That's the best you can do. Also, when you want to compare the output of the "corrected" signal, then - unless you use a soundcard that has a DC-coupled output - the DAC will also introduce distortions, changing its shape by eliminating the frequencies below ~20 Hz. So your measurement will be off, and the shape of the output will differ from the shape of your digital wave. So unless you use a DC-coupled soundcard, this won't work well, and if you use a DC-coupled soundcard, then this whole 'correction' is unnecessary. -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp
