As spotted recently on the “prosthetic knowledge” tumblr site – the Holographic Whisper three-dimensional spatial audio speaker system. (The slightly-over-the-top-futuristic-tech-style promotional video is included below…)

The creators propose a “sound-point method” that enables control of “aerial audio distributions more flexibly and more precisely in comparison with conventional superdirectional (sound-beam) loudspeakers. This method can generate and vanish the sound sources freely in air. These point sound sources can deliver private messages or music to individuals.” Unfortunately, there is no clear link to the mentioned research paper, and it doesn’t look like a prototype has been developed at this point. But it certainly warrants further exploration – I’ve been intrigued for awhile with the idea of creating a sonic installation in a space that could record the voices of attendees, and then play back segments of those recordings to future attendees with the audio being targeted (to be heard) at the same spatial location that the voices were recorded…a sonically “haunted” room filled with the voices of ghosts from past visitors.