The Hang is a recent musical instrument created by Felix Rohner and Sabrina Schäre in Switzerland in 2000. Its origin lies in the 1970s the classic Trinidad steel drum, which sparked a new craze throughout Europe and caught the attention of Rohner who has been playing the steelpan for the last 20 years. At some point, presumably to test the sound, he flipped his concave pan into a convex position. The sound that came from it was like nothing anyone had heard before: crystal clear, mesmerizing and almost transcendental. The Hang, composed of two half-shells of steel sheet glued together at the rim, uses some of the same principals as the steelpan, but has been modified so that it resonates, creating layers of different notes. It took the Swiss partners a few years to perfect their invention.

http://www.deezer-blog.com/curious-sounds-the-hang-instrument/