JACK Audio Connection Kit (JACK) is an open source audio connection and routing system for professional audio production applications. It enables users to connect different audio applications, allowing them to share audio between them. This can be used for a variety of tasks such as recording, playback, mixing, and routing audio. By connecting several pieces of software, users can record and mix audio with greater flexibility and control. JACK also supports networked audio, allowing applications on different computers to communicate with each other in real-time over a network. JACK is compatible with most popular audio applications for Windows, Linux, and Mac OS X.
Loopback is a very easy to use application with a clear and easy to understand GUI. I could never really understand the configuration of the JACKAudio application or get it to work properly. While Loopback has worked immediately after I installed it.