With certain sound cards, you can select the audio source for Skype calls, switching between your microphone and desktop audio during a call. If your sound card doesn't support this feature, you can play music during Skype calls with third-party plugins. Some of these plugins offer many other features, such as language translation and message encryption.

Enable Stereo Mix

To find out if your sound card supports stereo mix input, open the Windows Sound menu by right-clicking the speaker icon in the system tray and choosing “Playback Devices.” Right-click the menu background and select “Show Disconnected Devices.” If the Stereo Mix option is displayed, right-click it and select “Set as Default Device.” Close the Sound menu, launch Skype and open Skype's Tools menu. Select the “Audio” tab and click the “Microphone” menu to display Skype's audio input options, which include any connected headsets and your sound card's stereo mix. To play music during a Skype call, switch the microphone input option to “Stereo Mix” and play a song on your computer during a call. You can't speak into the microphone while Stereo Mix is selected, but any music playing on your desktop is audible to your caller.

Install Third-Party Plugins

Download and install an audio plugin, such as Clownfish, TunesUp or Skype Audio Player (links in Resources). These plugins are free and enable you to select an audio file to play during a Skype call without losing the use of your microphone. Each plugin's interface is straightforward and includes playback controls and a file browser button for selecting and playing music. Clownfish also includes several language translators, call recorders and a talking robot with artificial intelligence. To enable Clownfish's music player, press “M” during a Skype call. An audio window opens and displays playback controls. By default, Clownfish launches automatically when Windows starts, but you may need to launch the other plugins manually after starting Skype.