Unity is one of the most used engines in the game industry and several extensions have been implemented to increase its features in order to create multimedia products in a more effective and efficient way. From the point of view of audio development, Unity has included an Audio Mixer from version 5 which facilitates the organization of sounds, effects, and the mixing process in general; however, this module can be manipulated only through its graphical interface. This work describes the design and implementation of an extension tool to map parameters from the Audio Mixer to MIDI external devices, like controllers with sliders and knobs, such way the developer can easily mix a game with the feeling of a physical interface.