Speakers vs Stereo Mix
Windows Vista made some major changes to audio controls. Popular "Stereo Mix" input become deprecated, so how we can record streaming audio? New feature introduced by Microsoft is a "Speakers" input. What's the difference?
Stereo Mix is a feature of sound card driver. It's mix together audio streams on hardware level.
Speakers is a feature of Windows. It's mix audio streams on software level before they reach the sound card.