Systems and methods for identifying musical sounds are provided. In one implementation, a method includes receiving a collection of sound identifiers. Each sound identifier in the collection identifies a sound. Each sound identifier is associated with a corresponding audio representation. The collection of sound identifiers is used to construct a hierarchy of sound identifiers where each sound identifier appears only once in the hierarchy of sound identifiers. The hierarchy of sound identifiers is arranged according to a musical similarity between the sounds identified by the collection of sound identifiers. A selection of a first sound identifier is received. The first audio representation corresponding to the first sound identified by the first sound identifier is unavailable. The second sound identifier identifies a second sound that is musically similar to the first sound identified by the first sound identifier. An available second audio representation corresponding to a second sound identifier is provided.