Redefining 5.1 is an interactive music installation for one person in which the user plays a real–time role in his or her musical experience. The installation space—ideally large—is defined by four middle–facing speakers in each corner of the room. The user stands in the center of the space for each session, which typically lasts about ten minutes. He or she is fitted with an enhanced set of wireless headphones that manipulates its received audio according to the direction in which he or she faces and the tilt of their head. Music appears in any combination of the four speakers plus in the headphones via a synchronized independent audio stream, thus creating a musical situation in which audio is heard at any one point in time from five sources (the 5 in 5.1). The video component (the .1 in 5.1) is a feature to be implemented in a further prototype.