05 August 2011

Stop Skype Auto Gain Control of the Mic on Mac OS X

Skype has got to introduce a GUI element to turn off the Automatic Gain Control (AGC) of the Mic on Mac OS X. I'm not sure if the newer versions of Skype has this feature, but I'm using Skype 2.8.0.866 on Mac OS X 10.6, and the way to stop AGC is as follows:
  1. Open the folder ~/Library/Application Support/Skype (this is in your own user folder's Library folder, not the whole system one).
  2. Open the file shared.xml
  3. Find the text string <VoiceEng>
  4. Underneath that string, add a new line with the text <AGC>0</AGC>
  5. Click on the Apple logo in your menu bar
  6. Open System Preferences...
  7. Click on the Sound preference pane
  8. Click on the Input tab
  9. Find the Input volume slider and drag the slider all the way to the right (or to wherever you desire)
  10. Done!
 If you keep the Sound preference pane open at all times while using Skype, you should be able to monitor whether the Input volume slider (representing the mic's gain) moves around automatically or not.

(edit: I was asked to provide a screenshot, but then the screenshot would be just all text anyway, so I'll show a bigger snippet of what the shared.xml file should look like here.

Originally, it may look like this:

... various text ...
<VoiceEng>
   <MicBoost>
... various other text ...

Change it to look like this:

... various text ...
<VoiceEng>
   <AGC>0</AGC>
   <MicBoost>
... various other text ...

Hope that helps.)

I can't believe Skype never thought to include the option to set the gain manually.  Sometimes, when the user finds the other party can't hear them talk (e.g. when there is a lot of background noise), they will talk louder into the mic, since doing that on a real phone will increase how loud the other party will perceive the user's voice to be.  But with AGC on, speaking louder into the mic causes it to automatically reduce the gain, making it impossible to compensate for a noisy environment!  Very frustrating...

3 comments:

Smil- said...
This comment has been removed by a blog administrator.
mlsci said...

Smil- wrote (but I decided to redact the email address):

Thanks for doing this man,
A problem dow..... Can´t find the string ""
Is it 2 quotes? I would be very happy if you screenshooted that particular area and sent it to me!

[email redacted]

Thanks!
August 14, 2011 4:11 AM

mlsci said...

Sorry Smil-,
Blogger mangled up my original post and the important strings came out as double quotes, etc. It's fixed above now. Let me know if it's still a problem.