“What Makes Sonification User-Friendly?” Exploring Usability and User-Friendliness of Sonified Responses

Sonification is a commonly used technique to make online data visualizations accessible to screen-reader users through auditory means. While current sonification solutions provide plausible utility (usefulness) to screen-reader users in exploring data visualizations, they are limited in exploring the quality (usability) of the sonified responses. In this preliminary exploration, we investigated the usability and user-friendliness of data visualization sonification for screen-reader users. Specifically, we evaluated the Pleasantness, Clarity, Confidence, and Overall Score of discrete and continuous sonified responses generated using various oscillator waveforms and synthesizers through user studies with 10 screen-reader users. Additionally, we examined these factors using both simple and complex trends. Our results show that screen-reader users preferred distinct non-continuous responses generated using oscillators with square waveforms. We utilized our findings to extend the functionality of Sonifier—an open-source JavaScript library that enables developers to sonify online data visualizations. Our follow-up interviews with screen-reader users identified the need to personalize the sonified responses per their individualized preferences.