Hi,
I had same problem with UR44C at macOS.
I want all sounds (youtube on browser, music app, … ) to hear in all mixes.
Apparently, at the system level setting, the sound source output can be only switched between mix1 and mix2 (and FX Bus) with “Audio MIDI Setup” application.
(After selecting Steinberg UR44C at Left panel, click “Configure Speakers…” button at bottom right, and change channels.)
I tried a lot, but after all, I decided to use an audio routing app to play sound on both mix1 & mix2 channels.
I had a Loopback app (Rogue Amoeba | Loopback: Cable-Free Audio Routing) so I used it, but a free app should do the same things.
My settings are like this attachment image.
The settings using loopback are as follows:
- Create virtual output device
- Set UR44C as monitor device
- Link sound source’s L channel to monitor’s channel 1&3, R channel to monitor’s channel 2&4
- Select this virtual output device at macOS sound output setting panel.
It’s just a workaround, but this is enough for me personally.