JACK is a professional sound server daemon that provides real-time low latency connections for both audio and MIDI data between applications that implement its API. The API can be used through either JACK1 or JACK2.

JACK Audio Connection Kit vs Virtual Audio Cable Comments
It does only support jack compatible applications, not virtual audio applications.


- JACK Audio Connection Kit is Free and Open Source






While JACK Audio involves a more complex setup and needs the server to be started to work, it's functionally the same as it allows audio routing between applications. Routing can be done between any app providing an option to select the JACK Audio driver.