Add MacOS Sound Volume Slider to Rackspace

Problem: How do I Add existing MacOS Audio Slider to Gig Performer current GP Rackspace?

Background: I use Gig Performer to manage diverse keyboard, sound modules and related tools including Hauptwerk Virtual Pipe Organs. I use the existing gadgets from Apple etc in the normal wiring - no problem with audio levels there.

1.  I found the clever “Proxy Audio Device” posting on GitHub that accesses the MACOS core audio. I installed it OK but the device was output only, while my UMC1820 mixer is input output.
2. Perhaps root problem is No Input in AMS's Audio device tool.
3. Please reply with any Tips, Videos, references to this or another solution!

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TIA
Celestian

Proxy Audio Device? This: GitHub - briankendall/proxy-audio-device: A virtual audio driver for macOS that sends all audio to another output

A virtual audio driver for macOS that sends all audio to another output.