Can anyone suggest a site to learn more about bandpass filters (don't need to be very accurate, just for lighting effect). I'm trying to build an audio spectrum analyzer and will be using Op-Amp based bandpass filters and LM3915 dot/bar display IC. Any help would be gratefully accepted. Joe -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body