This isn't as much as a sound bomb and just a sound motion sensor. Soundbomb is the work of Felix Hardmood Beck. There is an integrated sound module built into a sphere that allows any kind of audio to be recorded. Once motion is detected, the audio will play back through the uniquely placed speakers—this is the part of the post where a sexual innuendo is placed based on a the visual representation of the speakers, but I'll just let the commenters handle it.
The only thing bomb-esque about this project is the manner in which it is designed and constructed. This project is described as a non-visual graffiti new-media-accessory, whatever the hell that means. They aren't available for purchase, but you have to apply to get the right to order one from the Felix, himself.
Flickr Album
Information Page [Via WMMNA]