• Open the Windows Sound menu by right-clicking the speaker icon in the system tray and selecting 'Playback Devices' to see if your sound card supports stereo mix input. Select 'Show Disconnected Devices' from the context menu by right-clicking the menu backdrop. If you see the Stereo Mix option, right-click it and choose 'Set as Default Device.' Close the Sound menu, launch Skype, and select Tools from the drop-down menu. To access Skype's audio input options, go to the 'Audio' tab and select the 'Microphone' menu. 
• This will show you any connected headsets as well as your sound card's stereo mix. Switch the microphone input option to 'Stereo Mix' and play a song on your computer during a Skype call to listen to music. 
• When Stereo Mix is set, you can't speak into the microphone, but any music playing on your desktop is heard to your caller.

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