Allan Spale aspale at evl.uic.edu
Mon Dec 17 15:45:38 CST 2001


Sorry for the delay in responding but I am checking my e-mail from home

In the image that I sent to you, Output 1 is where EVL's speakers are
connected.  It is a bit weird because we are first connecting these
outputs into the "Mackie Mixer" output (output 3), and then connecting the
output from the mixer directly to the speakers (without using the matrix).
So in your case, I would use output 3 as a reference for considering what
is connected to your speakers.

To try to generalize the situation, it seems that echo cancellation works
well when you send any sound source that will be coming out of your
speakers into some output that is not being used (here, output D was
used).  Then choose to echo cancel on that output.

But this is from the world of AP 400 that I somewhat know.  I am not sure
how to proceed (contact Gentner, read the manual, talk to people on AG
MUD, etc.).

Best of luck.


 On Mon, 17 Dec 2001, Mustafa Varank wrote:

> Allan,
> Thank you for the advices but XAP 800 does look different. There are 
> processors ( no sub?) on XAP800 and you should set "EC Reference and PA" 
> differently. Even i tried to set it, it did not work...I am doing something 
> wrong but i could not find...
> Could you please tell me also where did you put speakers on your sample 
> matrix picture?
> I will be waiting to see the updated web site...
> Thanks,
> Mustafa
> At 03:26 PM 12/16/2001 -0600, you wrote:
> >Mustafa,
> >
> >I have been working on creating a more up-to-date Gentner configuration
> >document, so I will attach an image from the document that will eventually
> >appear in the AGDP.
> >
> >I am not sure how ifferent the XAP 800 is from an AP 400, but I would
> >imagine that the echo cancellation should be similar.
> >
> >In the matrix, notice that Output D is labeled "Ghost Output".  This
> >output, which should have nothing connected to it physically, will be used
> >in echo cancellation.  This is demonstrated by looking at the bottom of
> >the image where you will select which output to serve as echo
> >cancellation.
> >
> >You want to echo cancel anything that would come out of your speakers so
> >that the Gentner does not think that this is regular audio going into the
> >mics (or something like that...I am not a complete expert on this audio
> >stuff).  Specifically, this would be sound from your telco and audio from
> >the AG.  The AG sound should be entering an input, and the sound from the
> >telco should be "Telco in".
> >
> >Create a crosspoint on the "Ghost Output" and the AG audio in row (RX from
> >AG) and the "Telco In" row.
> >
> >In the "Echo Cancellation Setup", select the output channel that
> >corresponds to the output designated as the "Ghost Output".  Please note
> >that the scenario described above is for the net-telco preset (preset 1).
> >For preset 2 (concerning the "Ghost Output" only and not the other mics,
> >inputs, outputs, an stuff), only have the telco crosspoint set in the
> >"Ghost Ouput" column.  For preset 3, only have the RX from AG (or whatever
> >you named that input that receives audio from the AG) crosspoint set in
> >the "Ghost Output" column.
> >
> >Also as far as general guidelines, make sure that your gain is not set too
> >high on the mics or this will cause echo.  Aditionally, make sure that
> >your mics are not too close to the speakers or else you may have echo
> >problems.
> >
> >Best of luck in figuring this problem out.
> >
> >
> >Allan
> >EVL at UIC
> >node-op
> >
> >
> >On Sun, 16 Dec 2001, Mustafa Varank wrote:
> >
> > > Hello,
> > > Can anybody send me some suggestions about how to set echo cancellation on
> > > XAP 800? I am having hard time to figure it out. And if you can send it
> > > today or  early monday morning that would be great...
> > > Thanks
> > >

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