Binaural headsets have mics in them that are 360-degree omnidirectional. They allow recording of things behind you as well as in front/lef/right. Check out the Sennheiser Ambeo Smart headset on Amazon.com, and you'll get a better idea of what these things are all about.--Matt Chao

P.S. the headphones themselves are stereo, but because of the mics, it adds a new dimension to sereo, kind of like surround sound, but at the headphones level.