Control Volume for Multi Monitor Setup with a Multi Output Audio Device?

[liammday]

While sending audio to multiple monitors simultaneously can be achieved through the MIDI controller, once this multi output device is selected as the system output the ability to control the hardware volume is lost.

[waydabber]

If you only want to control the volume via the keyboard on the display, you should

1. Select this:

2. And also select this:

4. Specify the audio device name to be matched for the display under Settings/Display/[display]/Hardware Control/Volume Control...

After this the volume keys will change the hardware volume for the display assigned to the audio device. You can still use the volume slider in the app menu of course.

[waydabber]

Sorry, it does work, no bug + you can control multiple displays this way if you define the same "Matching audio device name" for multiple displays (this should be the name of the composite audio device).

[waydabber]

(note: updated the steps with a crucial missing item)

[tommycusick]

How do you get to the "Matching audio device name" screen from step 4 if you are using Apple displays? My Hardware Control section just has a single toggle.

[waydabber]

Apple displays don't need BetterDisplay's DDC control for volume adjustments, they are natively supported by macOS.

[tommycusick]

Ah, I should have clarified— similar to OP, I’m trying to control the volume of two studio displays that are grouped as a multi-output device (whose volume macOS thinks it can’t control).

So you’re right that solo Apple displays don’t need this functionality, but given how multi-output devices work, I need BetterDisplay or something else to intercept and apply volume controls.

For what it’s worth I’m also fine with it if you decide mine is too niche a use case to support. I just wanted to check since I saw from this report that the functionality already existed in some form and was hoping I wouldn’t need to purchase/install multiple apps to accomplish the same thing with my setup.

[Edit October 27: For posterity, this free app solves the problem well: https://github.com/rlxone/MultiSoundChanger]

[liammday]

Hey, Thanks for the explanation. I think the issue is that when a virtual audio device is selected as the system output it takes over control of the system volume controls (I just get the denied symbol when I try and use the keyboard controls). If I have the displays match the virtual audio device I can only get one of the displays to function. The BetterDisplay controls still work as expected. Not to worry. I imagine I can’t have it both ways if I want to combine audio outputs but also use the virtual audio device. Thanks for the help.

…

On 12 Sep 2023, at 15:29, waydabber ***@***.***> wrote: Also you should be able to tie together multiple displays like this. At least that's the theory. In practice this does not seem to work in the v2.0.9 version, there might be a bug there. :( — Reply to this email directly, view it on GitHub <#2194 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AII3HOLUAMM2FNL5PAR35H3X2BWUNANCNFSM6AAAAAA4UZ6MKM>. You are receiving this because you authored the thread.

[waydabber]

No, if you set up like explained, the app will take over audio keyboard control. Just tested it with a multi output device. Of course you need to have native audio keys set up properly in the app with accessibility enabled etc.

So all in all, the above setup should work fully with a multi ouptut device configured to output to two displays, the app should and does control both display's audio via DDC this way.

[tim-tsui]

I setup a multi-output device for 2 monitors and the macbook pro speakers and while I was able to get keyboard volume control working using the instructions above for the monitors, the MBP speakers can't be controlled. I was unable to find the setting in step 4 for my built-in display. Is it possible to control the MBP speakers along with the 2 monitors?

[waydabber]

That is not be possible currently I am afraid. :(

[tim-tsui]

Thanks for the quick answer. Sadly my monitors don't have any bass so I was hoping to include the MBP to provide some.

[oyassern]

the only way i found it possible to achieve this is by using "SoundSource" app, you can create a multi output device (MBP Speakers & screens $ Ext Speakers) and control them from the keyboard volume controls, unfortunately i couldn't find any native solution to this

[aonez]

In case someone else needs this, I've modified MultiSoundChanger to use BetterDisplay when needed:
https://github.com/aonez/MultiSoundChanger/releases/tag/1.0.1-BetterDisplay

In my use case MultiSoundChanger was changing the volume of two out of three of the multi-output device devices (😅), leaving the display speaker untouched. Only BetterDisplay handles the volume of the display so this version integrates with it to change the volume.

[waydabber]

Nice!

[waydabber]

This issue (integrating DDC control to multi-output devices) comes up from time to time. Maybe you should have a separate discussion about it and it should somehow be made more accessible to others.