Multiple USB Audio Interfaces on macOS

setfield

(I've already tried Aggregate and Multi-Output Devices in Audio/MIDI Setup)    

I have an Audio4C and a Focusrite Scarlett 18i20 (3rd Gen) both connected USB-C to my Mac. No matter what set of options I've tried (see above) I cannot an audio signal on channel one and two on the Audio4C to play through my Scarlett.

In Sound Studio (macOS app) selecting "Monitor Playthrough input to output" enables the A4C input to play through the Scarlett. Is there a way to do this without having an app open? Should the OS be able to route the audio without using a DAW or audio editing app? It is entirely possible that I am using the Aggregate and Multi-Output Devices improperly but I've followed the instructions on Apple's site and... Nada!

Thank you!

tsho08

If you want an input from one interface to output on another interface you have 2 options.
1) Use an app/software to route the input from one to the output of another.
2) run a direct through the first interface from inputs to output and physically connect the outputs of interface 1 to the inputs on inteface 2 and then you can go direct through on the second interface.

I would use option 1.

There is no directly routing from one connected device to the other that's native on Mac OS. You need to use software.

setfield

tsho08 said:

There is no directly routing from one connected device to the other that's native on Mac OS. You need to use software.

Thank you for the response. I was afraid that’d be the answer but it makes sense. Looks like Loopback to the rescue!