Linearity, orthogonality, and resolution of psychoacoustic sonification for multidimensional data

Sonification is the use of sound to communicate data to a listener. In sonification designs that lack psychoacoustic considerations, dimensions tends to be perceived as nonlinear, interfering, and as having a low resolution. As a solution to these issues, we developed a “psychoacoustic sonification,” in which single dimensions or variables of multidimensional or multivariate data are mapped to independent psychoacoustic quantities instead of orthogonal physical quantities. Distances along different direction are mapped to the speed of cyclicchroma change, the beat frequency, the degree of roughness, brightness and fullness. In this paper we present results of 3experiments that evaluate the linearity, orthogonality, and resolution of the dimensions. In experiment 1, participants identify a sonified target field in multiple two-dimensional spaces. Results indicate the orthogonality of the dimensions. In experiment 2, the sonification guides the participants through a two-dimensional space to find an invisible target. The results verify the linearity and orthogonality of the dimensions and indicate a high resolution. Experiment 3 is a JND experiment according to the transformed up-down method, which demonstrated the high resolution of the dimensions. We conclude that applying psychoacoustic knowledge in the signal processing of sonification is a powerful tool for multidimensional data sonification.