Hi Chrisir,
When I clap strongly it detects and shows the significant difference of wave intensity ( I think amplitude not intensity ) in the sketch window but by default it always shows the "LEFT" and never shows "MIDDLE". And when I bring my any source of sound near to RIGHT mic it detects as "RIGHT" and LEFT as LEFT
Yes, I have stereo mics in my laptop. I have tested it with some other audio recording software and they work perfectly.
I have Dv6226tx Hp pavilion laptop