Connecting user interface elements such as buttons and sliders to audio parameters is a fundamental technique for creating interactive audio experiences in the browser. When you use event listeners on UI controls, you can respond to user actions and update sound properties in real time. For instance, a slider can be mapped to the pitch of a synthesizer so that moving the slider changes the note being played. Similarly, a volume slider can adjust the loudness of the sound, and another slider can control the amount of an audio effect like reverb.

This mapping is achieved by listening for events such as input or click on HTML elements. When these events occur, the handler reads the new value from the UI control and updates the corresponding parameter in the Tone.js synth or effect object. This direct connection allows users to shape and manipulate sound characteristics instantly, making the audio experience engaging and responsive. It also enables the creation of custom instruments, effects panels, or interactive installations where users can explore sound creatively.