When it comes to broadcasting an Internet radio program and being able to mix the audio from media players, Skype and your voice, there is not audio driver more important than Stereo Mix. Stereo Mix allows you to do every thing without the need to use an external audio card and physical 3.5mm cables.
Personally, I prefer the two audio card set up in using an external USB audio card that Skype will use where the audio coming off Skype is routed with inexpensive 3.5mm cables to the internal audio card that will then mix the Skype Audio with audio coming from media players and send it out on your broadcasting stream. The reason I prefer this set up is because when using broadcasting software like Sam Broadcaster, when your mic is turned off in Sam while you play audio clips or advertisements, you don’t have to worry about not talking to someone on Skype while playing audio clips and having that go out over the air when you don’t want it to.
However, if you choose to use Stereo Mix to mix your audio coming off different applications, you can get it done no problem except for the aforementioned issue with unwanted sounds going out over the air. One advantage you have with using Stereo Mix as opposed to the two audio card set up is that if you use a conference line to take calls from listeners or allow them to listen over a regular phone line, any audio you play will go out to those dialed in by phone or Skype without needing to set up external speakers to not only monitor what you play but then using your physical microphone to grab audio off those external speakers and send it out to those on the phone.
Many people who have updated their Window’s operating systems to Windows 7/8, many times the Stereo Mix audio codec is missing. You can check to see if your Windows operating system has Stereo Mix installed by right clicking on the little speaker icon in your taskbar, then left click on recording devices. After the window appears that shows all your audio devices, right click on an empty spot on the window and then click to tell it to show “disabled” or “disconnected devices”. If you see Stereo Mix and it is disabled, simply right click on it and “enable” it.
If you find that you do not have the Stereo Mix codec, you can download it and install it on your computer as illustrated in the video below.
Once you have installed Stereo Mix and enabled it, to use it to mix audio from various applications to broadcast on an Internet radio stream, simply choose Stereo Mix as your default device for the mic in all applications. Sometimes, you may have to take an extra step in enabling Stereo Mix in your “playblack” device as has been also noted in the video.