if you know these 'virtual surround' programs that can emulate sound coming from =any= point in 3d space with a pair of earphones, check this out - train a person to discern between few audio 'sources' in 3d space, then train him to hear more than one source at a time, and with further training .... perhaps you could actually 'see' simple 3d models (or in the worse case, you have an interesting alternative output device..) I wonder how this would work with the blind. they usually have phenomenal hearing. by the way I believe psychoacoustic models today are not advanced enough for the job.-- supershnitzel, Oct 24 2005 On discovery they have shown blind people recognizing buildings, trees, dogs, go shopping and even shake hands with similar technology. What they do is wear a special pair of goggles that acts as sonar. the sound output is converted from ultrasound to ordinary sound and sent to the person's ear. A blind sportsman was even shown to follow a person on a race track for excersize purposes.-- kamathln, Oct 24 2005 Permit me to be skeptical about shaking hands using sonar. (Unless you're simply detecting which direction the shakee is in, and relying on him/her to grab your hand and pump it wildly.)-- DrCurry, Oct 24 2005 random, halfbakery