Mains hum at 50Hz or 60Hz is one type, but there also are many other possible sources of hum including ground loops:
http://en.wikipedia.org/wiki/Ground_loop_(electricity) which we had in one venue where we had presenter PC audio connected to a mixer, and eliminated by putting a passive DI with ground lift between the presenter PC and mixer: http://en.wikipedia.org/wiki/DI_unit Regards Stephen -- Stephen Marquard, Acting Director Centre for Educational Technology, University of Cape Town http://www.cet.uct.ac.za Email / IM (Jabber/XMPP): [email protected] Phone: +27-21-650-5037 Cell: +27-83-500-5290 >>> Greg Logan <[email protected]> 11/30/2011 7:40 PM >>> On 11-11-30 11:36 AM, Micah Sutton wrote: > Audio issues like this can be notorious to track down. The first place I > would look is the capture agent and move up the audio chain from there. > Try turning the capture volumes down and see if this reduces the hum. > Anything higher than about 60% input volume we've found adds a lot of > noise to our recordings. We try to keep the signal going to the agents > high, and capture at a lower volume. This is called ground hum, and is quite common: http://en.wikipedia.org/wiki/Mains_hum We have it too, and yeah the best bet has been to turn down the recording volume. G > Micah > > On Nov 30, 2011, at 11:19 AM, Steven M Lichti wrote: > >> Hi all, >> >> Are any of you experiencing humming/buzzing on recordings? We can't' >> find the hum or buzz anywhere in the audio system, but on the >> recordings done by MH (on the Linux boxes), we're still getting >> background buzzing. >> >> Are any of you seeing (hearing) this as well? >> >> --Steven. ### UNIVERSITY OF CAPE TOWN This e-mail is subject to the UCT ICT policies and e-mail disclaimer published on our website at http://www.uct.ac.za/about/policies/emaildisclaimer/ or obtainable from +27 21 650 9111. This e-mail is intended only for the person(s) to whom it is addressed. If the e-mail has reached you in error, please notify the author. If you are not the intended recipient of the e-mail you may not use, disclose, copy, redirect or print the content. If this e-mail is not related to the business of UCT it is sent by the sender in the sender's individual capacity. ### _______________________________________________ Matterhorn-users mailing list [email protected] http://lists.opencastproject.org/mailman/listinfo/matterhorn-users
