Expressive potential

Expressive potential is the degree to which a given music control interface (input device) enables a musician to control musical expression. An interface with low expressive potential enables control over a narrow range of musical expression, no matter how virtuosic its player, whereas an interface with high expressive potential enables control over a wide range of musical expression. Expressive potential is independent of how that potential was, is, or will be realized in any given composition or performance. This independence allows the expressive potential of new musical instruments & interfaces to be compared and contrasted objectively with traditional musical instruments.

The concept of expressive potential is closely related to the concept of affordance, i.e. all "action possibilities" latent in the environment, objectively measurable and independent of the individual's ability to recognize (or realize) them.

One possible metric for expressive potential is the number of degrees of freedom provided by the interface. The more degrees of freedom, the more independent expressive variables a musician can control independently during performance.

The development of new interfaces to control musical expression is an active research area, supporting an annual conference, New Interfaces for Musical Expression.