Thanks for your details. Seems you are right after I did some more testing.

Regarding the Inputs:
- I do not use Zoom or Skype. Just Facetime and Teams for Business (but in Safari/Firefox, not the App)
- What surprised me most is Facetime: Even if i can select individual Devices in Microphone and Output Settings, it seems to simply ignore that. It always uses the IN/Out Device as defined as "System Default"...
- In Teams(Browser), i can select only the Input. Which works fine. But Output is unselectable. So it uses always the System Default.

And - of course, as Safari, Finder, AppleMusic, and the other Standard OSx Apps always use the "System Default" Out Device -  You are absolutely right. Maybe i was not clear enough at this point.
But what really wonders me, is the behavior of FaceTime.

And sorry, chj if i got a little off topic regarding your question. l tried to sum up my understanding here.

Thanks!

oli77sch wrote:

Hi
Sadly this is a limitation of macOS / core audio. Only applications with the support for multichannel audio can address specific channels. For the macOS Finder and applications like internet browsers, Zoom, Skype and such always the first two channels are selected automatically.

oli77sch, maybe i misunderstood sth?

As i already posted here: https://forum.rme-audio.de/viewtopic.ph … 47#p217347

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I recommend to read and understand the complete AMS Manual, play around with the Settings and create your own Setup: https://support.apple.com/en-gb/guide/a … 6/mac/14.0

If you understand the principle, you will come to the point that every Source, from "Standard" Apps (Browsers, Youtube, Apple Music, Zoom, Teams, etc...) have its own Volume Sliders on Macs... (And TM for the RME Unit). So. it makes no sense for a "third Layer Mixer" like Windows does.

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Hi
Yes, my answer above wasn’t precise and not entirely correct, I’m sorry for the confusion.
It’s true for the inputs with some apps (Zoom or Skype for example), only channels 1/2 are usable and there is no way to change that.
But on output side, the desired channels (two for stereo, more for 5.1, 7.1…) can be set in Audio/Midi app, as you write @maggie33. But still it’s not possible to select different stereo output pairs for particular apps. For example, you can’t set analog out 1/2 for Safari browser, SPDIF out for Zoom and ADAT 7/8 for the Finder preview at the same time.
To avoid misunderstandings: what I say is related to the case when one has selected the RME interface as system audio hardware (instead the built in one). I’m not referring to aggregate devices or such! To my understanding, chj asked only for this use case (Digiface USB selected as system audio hardware).

Hi
Sadly this is a limitation of macOS / core audio. Only applications with the support for multichannel audio can address specific channels. For the macOS Finder and applications like internet browsers, Zoom, Skype and such always the first two channels are selected automatically.

oli77sch, maybe i misunderstood sth?

As i already posted here: https://forum.rme-audio.de/viewtopic.ph … 47#p217347

-------

I recommend to read and understand the complete AMS Manual, play around with the Settings and create your own Setup: https://support.apple.com/en-gb/guide/a … 6/mac/14.0

If you understand the principle, you will come to the point that every Source, from "Standard" Apps (Browsers, Youtube, Apple Music, Zoom, Teams, etc...) have its own Volume Sliders on Macs... (And TM for the RME Unit). So. it makes no sense for a "third Layer Mixer" like Windows does.

---

A basic Overview about the different Types in CoreAudio:

In the Audio MIDI Setup app on your Mac, select a stereo audio output device from the list and click "Configure Speakers...", as the Apple guide describes here: https://support.apple.com/en-gb/guide/a … 6/mac/14.0

1) You can freely assign the the "Standard Apps" Stereo Channels in Audio Midi Setup (for playbacks). Just select the pairs, you want - (other then 1/2) in this picture:

https://help.apple.com/assets/6530581E5 … f7ce9b.png

2) Or if you want to configure your Multichannel Setup, other than the defaults:

https://help.apple.com/assets/6530581E5 … bb271d.png

3) You can even setup multiple "Aggregate Devices", where each holds you freely defined configuration - here you can combine your RME Unit, with other Devices, like USB Headsets, internal speakers, etc... Just give each a unique name, and you can direcly activate/switch it in the Settings app (or, if active,  via the speaker icon) in the Menu bar. Important Note: Set the Clocksource and Drift Correction accordingly!

https://help.apple.com/assets/6530581E5 … 2c999b.png

4) Or - you can define one (or multiple) "Multi-Output Device/s" Here the Stereo Out Signal ist replicated to other Hardware simultaneously. Set the Primary (Master-) Device and Drift Correction accordingly!

https://help.apple.com/assets/6530581E5 … c51434.png

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Edit: Just saw this post: https://forum.rme-audio.de/viewtopic.ph … 78#p218578

So, to sum up, i added more details regarding Sample Rate and Drift Correction with "Aggregated Devices".
Taken up from:
https://support.apple.com/en-gb/guide/a … 6/mac/14.0

1) Sample Rate

• All devices in the aggregate device need to have the same sample rate. The sample rate of each device should match the sample rate of the device chosen from the Clock Source pop-up menu.

2) Drift Correction

    2.1) Setup 1 - Example: RME Unit, Macbook Mic/Speakers and a USB Headset

• If all of the devices in the aggregate device aren’t synchronised through hardware, click the Clock Source pop-up menu, then choose the device with the most reliable clock. Select the Drift Correction tick box for each device.

    2.2) Setup 2 - Example: 2 RME Units (i.E. FF802 and UCX II) where both RMEs are connected via AES and FF802 is the Master in RME Settings, Macbook Mic/Speakers and a USB Headset are also included in the "Aggregated Device"

• If some of the devices in the aggregate device are synchronised through hardware, click the Clock Source pop-up menu, then choose the hardware synchronisation’s primary clock source (=FF802). Select the Drift Correction tick box for each device that isn’t synchronised through hardware. (=Macbook Mic/Speakers and a USB Headset)

2.3) Setup 3 - Example: 2 RME Units (i.E. FF802 and UCX II) where both RMEs are connected via AES and FF802 is the Master in RME Settings, no other Devices included in the "Aggregated Device"

• If all of the devices in the aggregate device are synchronised through hardware, click the Clock Source pop-up menu, then choose the hardware synchronisation’s primary clock source.(=FF802) Make sure none of the Drift Correction tickboxes are selected.

On Windows, these pairs are available once setup in the AsioDriver panel. How to do this on Mac? In the AudioMidi MacOs panel, everything is "greyed out" and cannot be manipulated.

Just now, I have to go via BlackHole to fetch the audio stream into some DSP sw (which finally will pour out again on RME soundcard). Working, but I wish for a complete solution from the RME software, like on Windows10.

Checked also with Reaper, and therein one can select stereopairs.

Thanks for any tip!