[AG-TECH] Transmission feeback

Robert Olson olson at mcs.anl.gov
Fri May 25 11:05:33 CDT 2001

If I understand what is being asked, I believe we are configuring the 
gentner for mix minus one. The gentner has a matrix mixer in it, and the 
signal we send back to the codec (audio capture PC) is the local 
microphones only, not the remote audio. (I'm going from the definition of 
mix minus that I found on http://www.telos-systems.com/techtalk/mixminus.htm).


At 04:47 PM 5/25/2001 +0100, Mike Daw wrote:
>I was wondering what part of the Access Grid coped with "mix minus one"
>audio, because, apparently, the AP400 does not do this. Without it (I am
>told), there is a problem with "transmission feedback" (i.e. awful howl!)
>when there are more than 2 sites communicating. I guess this can't be a
>problem with so many sites up and running, so how is it done?
>This question was asked by our suppliers of the AP400. (In case you were
>wondering how such an obvious novice came to be asking such a technical
>question when our kit has not even arrived...!)
>This supplier has literally just emailed me and added:
>"We have had problems dialling older American 'mulitpoint Bridges" as in
>America the technology has been around longer and in the old days the
>endpoint had the "mix Minus 1". In England our systems assume the Multipoint
>bridge has the "Mix minus 1". This means if you try to "multipoint" several
>English endpoints without this facility in your "node" you will get "all
>manner of problems". "!"

More information about the ag-tech mailing list