Photosounder

Photosounder is a sound editing and synthesis tool that allows you to edit sound in powerful new ways by turning the entire sound into an image that describes accurately every of the sound's features. It can therefore accomplish things that are simply impossible with any other tool. It also allows you to use images, all sorts of images, to create new sounds that are nothing like what we know, or perhaps even more interestingly to create images that produce familiar sounds.

http://photosounder.com