> Hi Michael, > > Michael Welter wrote: >> the codecs I use? Filter-out everything between, say, 55 and 65Hz? > > Notching may not be that effective, as it will not deal with the > harmonics. The analogue to digital converter should already be > filtering below 300Hz, so you probably have quite a lot of hum if it
300Hz is pretty high to filter out... it's still well within the rage of voices. To compare, 300Hz is about a diatonic concert D. > gets through that. There isn't much you can do to eliminate the hum > your callers hear. For your own hum, additional filtering may be > beneficial. This could be implemented by analogue or digital filters. > Simple RC analogue filters probably would not be sharp enough to give > much benefit, so you would need a more complex active analogue filter. > A digital filter would require no hardware changes, but you need > someone who knows what they are doing to implement it for you. Then how about something like http://www.digitimer.com/research/quest/? It seems to take care of harmonics and specifically targets the 50/60Hz range. Nick _______________________________________________ Asterisk-Users mailing list [EMAIL PROTECTED] http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
