> Depends on the kind of output. If audio in the range of human hearing, >=20 > a .1% change in Pitch should be readily discernible in much of the range. Pitch possibly, volume I doubt it. Really what he is adjusting is equivalen= t to the volume of light. --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .