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   July 2008
Vol. 24, No. 2

A Technology Newsletter for Extension Specialists

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Centra Microphone Feedback
by Steve Giesel

Some of you have been experiencing feedback problems with your new laptops when participating in a Centra conference.  I had a News & Notes item about this issue on the ETCS home page for a time, and I’ve reprinted the instructions below.  Look for a Quick Tip item for future reference as well.

I know the problem can be aggravating, but fortunately the fix as outlined is simple.  Be sure to test your existing microphone on another computer, and/or try a working mic on your machine when tracking down the problem.  This will quickly eliminate the microphone as the problem.

I know of at least one instance where no microphone could be made to work at all.  It turned out this was a hardware failure in the laptop sound card.  If you’ve made sure you have a working mic and have completed the fix instructions but still can’t make it work, it may be time to call ETCS.  You can contact
Charlie Baerwald at baerwaldc@missouri.edu, or
Chris Pfingsten at pfingstenc@missouri.edu if your efforts have failed in this regard.

ETCS is happy to assist you, but we do handle a high volume of call traffic—so please be sure to exhaust all avenues prior to calling, thank you.


  1. Go to Start » Control Panel » Sound.
  2. In the window that opens, click the Recording tab.  You should see icons for your built-in and external mic, as well as icons for "Line In" and "Phone Line."
  3. Right-click the built-in microphone icon.
  4. Click Disable.  The icon should disappear or be marked with a red "X."
  5. If both of your microphone icons disappear, right-click one of the remaining icons and choose, Show Disabled Devices.  Both microphone icons should reappear.
  6. Right-click the external microphone icon and choose Enable.  This should take care of your problem.


Last Revised: 08/04/08



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