Soundflower For Mac
Allow different applications to access your sound card. Soundflower is a free audio system extension that allows applications to send audio to other applications.
Soundflower allows audio applications to send and receive audio without other support needed.
If you want the application to interact with other applications through the sound card, select Soundflower as the output device in the first application and Soundflower as the input device in the second application.
If an application does not allow you to specify an audio device, you can make Soundflower the default input or output device in the Sound panel in System Preferences, or with the Audio MIDI Setup utility application which is the only slightly complex part.
You might hear noise at first when you set the audio channel and if so, the developers recommend increasing the buffer size of both applications (set in each application). Note that if more than one application sends its output to the same channel, audio will be mixed.
The practical use of Soundflower includes conducting interviews with both voices. So instead of recording an interview with Skype and only hearing one voice, Soundflower allows you to record both voices for more professional production.