[AG-TECH] Echo Cancellation

Jay Beavers jbeavers at microsoft.com
Fri Apr 18 00:11:08 CDT 2003

The software echo canceller that ships in Windows XP isn't designed for use in room based conferencing scenarios, it was optimized for use with a single microphone in a 10'x10' room for desktop conferencing scenarios.  We've had extensive discussions with the Microsoft Research Signals Processing team and the Real Time Collaboration product group around Access Grid scenarios, and they are continuing to improve our software echo cancellation technology.  However, the work required to handle advanced scenarios like 4-16 microphones distributed throughout a room is quite involved.
I've been very happy with the Gentner XAP product line for this scenario and I'm especially impressed with the improvement in both the software and hardware between the AP and XAP series.  We ran a trial distance education class using an AP400/800 pair on both sides of the wire in spring 2002 and we're a few weeks into a new trial this spring using an XAP400/800 pair and the audio quality difference is very noticeable and my ability to adjust the XAPs to the room's sound signature was vastly improved.  What took about four two hour audio adjustment sessions last spring to get right I did in two fifteen minute sessions this year.  Caveat applies that I'm also considerably more knowledgeable about room acoustics and how to tweak Gentners from the experience I've gained, but there are important features like very good noise reduction and much improved gating control in the XAPs that helps make a big difference in results.
 - jcb


From: owner-ag-tech at mcs.anl.gov on behalf of jzeeff at internet2.edu
Sent: Thu 4/17/2003 6:07 PM
To: Michael Gates
Cc: ag-tech at mcs.anl.gov
Subject: Re: [AG-TECH] Echo Cancellation

Lately there have been a number of ASPI echo cancelers available on
Ebay for $85/pair.

Looks like this one expires in 28 minutes with no bids.


I hear the software echo canceller that Microsoft put into XP works well.
Can it be made to work with an AG node?

  On the other hand, do software EC
> solutions work?  I've seen that there are some out there... Anybody try any
> of them?

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