Techniques described herein allow a user to create and modify a sound design in a user interface. For example, a user imports a sound file into the user interface, where the sound file is displayed graphically along a timeline. The user can then insert multiple control points along the timeline. The control points display the sound properties of the sound file at the selected points in time along the timeline. Accordingly, the user uses controls provided in the user interface to adjust and modify the sound properties displayed on a control point. The modifications the user makes to the sound properties are saved to the sound file.