Harmonix Music Systems (or simply Harmonix) is an American video game development company based in Cambridge, Massachusetts in the United States. It is known for its many music video games.
Harmonix is perhaps best known as being the developer of Dance Central, Rock Band and Fantasia: Music Evolved, as well as being the original developer of the Guitar Hero series before development moved to Neversoft and Vicarious Visions. More: en.wikipedia.org.