Interactive Music with Active Audio CDs

With a standard compact disc (CD) audio player, the only possibility for the user is to listen to the recorded track, passively: the interaction is limited to changing the global volume or the track. Imagine now that the listener can turn into a musician, playing with the sound sources present in the stereo mix, changing their respective volumes and locations in space. For example, a given instrument or voice can be either muted, amplified, or more generally moved in the acoustic space. This will be a kind of generalized karaoke, useful for disc jockeys and also for music pedagogy (when practicing an instrument). This demonstration shows that this dream has come true, with active CDs fully backward compatible while enabling interactive music. The magic is that “the music is in the sound”: the structure of the mix is embedded in the sound signal itself, using audio watermarking techniques (patent pending).