vb-audio.com
VB-CABLE is a virtual audio device that works as a virtual audio cable, forwarding audio coming into the CABLE input to the CABLE output. It is a Windows audio driver that, per the page, can be used without configuration and works with audio applications using MME, KS, DX or WASAPI interfaces. A macOS package is also listed. VB-CABLE is offered as donationware, with license pricing left to the user's means or usage.