earless headphones

Came across an ad for these things, which apparently work by conducting sound through the temples and bones behind into the ear bones, rather than via the ears themselves. They have them built into sweatbands for joggers, and underwater versions . Anyone come across these - are they novelty or hifi?

http://www.dowumi.com/eng_product/html/view.php?no=49&categoryid=17

http://www.dowumi.com/eng_product/html/view.php?no=43&categoryid=17

 

I have used a military version of the above, it works. Just not mid-fi let alone hi-fi.

 

Not sure how well the ipod would respond to going underwater...