The MIT Technology Review suggests that Microsoft researchers have abandoned saving their Zune music player* to find ways to play music in 3D. The idea is to have speakers that target sound to a certain location so you don’t need headphones. The site says:
A software architect at Microsoft, recently began work on an algorithm that, in theory, will be able to direct sound from a set of speakers–ideally embedded in a computer monitor–into a person’s ears, effectively creating virtual headphones; just a few inches outside the focal point of the sound waves, the volume dramatically fades away. Crucially, says Tashev, his algorithm could be used by a wide range of inexpensive speakers that could be put into computer monitors.