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.

There are many alternatives to Virtual Audio Cable for Windows if you are looking for a replacement. The best open source Windows alternative is JACK Audio Connection Kit. If that doesn't suit you, our users have ranked more than 10 alternatives to Virtual Audio Cable and three of them are open source and available for Windows so hopefully you can find a suitable replacement. Other interesting open source Windows alternatives to Virtual Audio Cable are Synchronous Audio Router and win-capture-audio.
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.

Synchronous Audio Router is a software-based audio routing driver for Windows. You can create any number of Windows audio endpoints, either playback or recording, and route them using any digital audio workstation software which supports ASIO, all with low latency.

An OBS plugin that allows capture of independent application audio streams on Windows, in a similar fashion to OBS's game capture and Discord's application streaming. This eliminates the need for third-party software or hardware audio mixing tools that introduce...

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.