USBlyd

USBlyd is a free and open-source audio routing and mixer application for macOS. It allows users to create complex audio configurations, such as routing audio from different applications to separate output devices or mixing multiple audio sources together. USBlyd functions as a virtual audio device, appearing in the macOS Sound Preferences pane alongside physical audio interfaces.

The primary purpose of USBlyd is to provide granular control over audio routing that is not readily available in macOS's built-in audio settings. Users can assign specific applications to different output devices, create custom audio aggregations, and manage input and output levels for each stream. This is particularly useful for musicians, podcasters, streamers, and anyone who needs to manage multiple audio sources and destinations simultaneously.

USBlyd is developed and maintained by H. Peter Anvin and is available under the MIT License. Installation typically involves downloading a disk image and dragging the application to the Applications folder. While the application itself is relatively straightforward to use, understanding audio routing concepts is beneficial for advanced configurations. Its flexibility makes it a valuable tool for users seeking advanced audio management capabilities on their Mac.