[AG-TECH] RAT : "Monodimensional" sound ?

John I. Quebedeaux, Jr johnq at lsu.edu
Thu Mar 26 20:43:15 CDT 2009

I can think of one instance, yes, when echo canceling is improperly setup -
canceling oneself off or the other side off inadvertently.

Long ago I remember this happening when someone's audio wasn't configured
properly for echo canceling.

Be sure that you are using only the audio coming from the remote site for
echo canceling reference. This is usually referenced as the 'speaker' as in
the audio that comes from your audio speakers - but that can be problematic
if you're reinforcing your own audio into your own room - i.e. If you're
hearing your own microphone in your speakers. Properly one should only
cancel the remote audio (from the computer/rat specifically).

One quick test, do you hear yourself when you speak even without any remote
sites set to speak? Is the audio card's loopback muted? (on windows, that's
the line in channel on the card is muted).

The only other thing I can think of is an audio card is monodirectional... I
forget the actual term.

Perhaps there is something else, but those are off the top of my head... And
perhaps they're not related... but I know to check these things!

-John Q.
John I. Quebedeaux, Jr.; Louisiana State University
Computer Manager LBRN; 131 Life Sciences Bldg.
e-mail: johnq at lsu.edu; web: http://lbrn.lsu.edu
phone: 225-578-0062 / fax: 225-578-2597

> From: Thibault Daoulas <thibault.daoulas at canterbury.ac.nz>
> Date: Fri, 27 Mar 2009 14:33:35 +1300
> To: <ag-tech at mcs.anl.gov>
> Subject: [AG-TECH] RAT : "Monodimensional" sound ?
> Hello everybody,
> I have been looking up into the archives, but couldn't find anything
> about it :
> Yesterday I had a meeting precisely to test a few things about the media
> tools, and it happened that only one person at a time could transmit
> sound, and like a walkie-talkie we had to tick/untick "talk" in the RAT
> interface to be almost able to discuss.
> Has anyone experienced it before ?
> Thanks,
> Thibault.

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