Sound - the oft-neglected sense for Software Engineering - is a crucial component of our daily lives, playing a vital role in how we interact with the world around us. In this paper, we challenge the traditional boundaries of Software Engineering by proposing a new approach based on sound design for using sound in modelling tools that is on par with visual design. By drawing upon the seminal work of Moody on the `Physics' of Notations for visual design, we develop a comprehensive catalogue of principles that can guide the design of sound notations. Using these principles, we develop a catalogue of sounds for UML and report on an empirical study that supports their usefulness. Our study lays the foundation for building more sophisticated sound-based notations. The guidelines for designing symbolic sounds for software models are an essential starting point for a new research thread that could significantly and effectively enable the use of sound in modelling tools.