1 Topic by Beauvais (edited by Beauvais 2022-11-05 16:47:34)

  • Registered: 2009-09-15
  • Posts: 25

Topic: Atmos / spacial audio playback on macs

I'm trying to get both the Apple Music and TV apps to output spatial audio to a 7.1.4 speaker setup. I have a Digiface USB which goes via ADAT to a Metric Halo 3d device which acts solely as B-chain / monitor controller. This works perfectly fine with a DAW, but I'm having issues with the playback of the two Apple consumer apps.

Specifically I can not get all channels to play back. A Dolby Atmos mix only outputs on six channels, in Totalmix it looks like a 5.1 mix (not sure if anything beyond the surrounds get folded into the surrounds or omitted). However if I play a 7.1 (no height speakers) mix the rear surrounds DO get a signal. It appears that anything beyond 8 channels get folded down to 6 channels, but 8 channels are fine.

I'm using these to test: https://music.apple.com/us/album/functi … 1608036078

Now my hunch is that the issue is the Digiface's grouping of channels into 4 Streams of 8 channels per ADAT connector and that confuses the decoder in Apple Music / TV.

Is this something that RME can fix or is this something Apple needs to sort out? The whole thing does seem a little flaky on Apple's side at this time (for example Atmos prefs in Music.app).

Edit: this is on a Mac Studio running 12.6

  • cigame
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  • From: Seevetal
  • Registered: 2007-05-03
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Re: Atmos / spacial audio playback on macs

I had the Music abo for a month and did not find any content with 7.1.4
Same in TV app.

UFX+, FireFace 802 FS, Digiface USB
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  • Registered: 2009-09-15
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Re: Atmos / spacial audio playback on macs

Well at least in theory anything that has the Dolby Atmos logo in the Music app should output to 7.1.4 if you define your interface as capable of outputting that in the Audio Midi Setup. But then who knows what's really happening there.

However the Functional Testing Album by Dolby Labs is quite clear about what it's outputting. And when I play track 6 to test the 7.1.4 layout with a voice speaking the channel names, everything beyond the side surrounds (i.e. the rear surrounds and the height speakers) gets folded into them. And truncated as I wrote above. On track 4 for 7.1 playback the rear surrounds to get identified correctly though. Hence my speculation about any channel count beyond 8 causing issues that result in a fold down.

  • Registered: 2009-09-15
  • Posts: 25

Re: Atmos / spacial audio playback on macs

Sorry for the double post. But when I create a virtual Rogue Amoeba's Loopback 12-channel interface and route that to the Digiface I get perfect 7.1.4 playback in Apple Music. So the issue is clearly between MacOS and the Digiface.

Should I consider this a bug and report to RME?

5 Reply by MC

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  • Registered: 2007-04-06
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Re: Atmos / spacial audio playback on macs

Are you using the Kernel based driver, v 3.28? It divides the number of available channels into 8-channel streams.

The current DriverKit beta driver 4.06 (this forum) exposes only one stream with all channels and might work then.

Regards
Matthias Carstens
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  • Registered: 2009-09-15
  • Posts: 25

Re: Atmos / spacial audio playback on macs

Thanks for chiming in Matthias. I was indeed using the old 3.28 driver.

Unfortunately the new 4.06 beta does not change anything about the behaviour, so I guess my hypothesis about the channel streams was wrong.

  • Registered: 2019-07-17
  • Posts: 9

Re: Atmos / spacial audio playback on macs

Did you tried to create an aggregate Device in Apple Audio-MIDI devices?
The Apple Music app can not handle a bigger matrix than 12x12 or 16x16.

https://support.apple.com/de-de/HT202000

Best regards from Cologne,
Stefan

8 Reply by MC

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Re: Atmos / spacial audio playback on macs

Sternthaler wrote:

The Apple Music app can not handle a bigger matrix than 12x12 or 16x16.

So all audio interfaces with higher channel count would fail? Where is this limitation mentioned?

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Matthias Carstens
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  • Registered: 2019-07-17
  • Posts: 9

Re: Atmos / spacial audio playback on macs

You can solve this problem with BlackHole. Download the 16 channel instance here:

https://github.com/ExistentialAudio/BlackHole

Use this driver for Mac sound device in system settings ->sound->output\input

Create an aggregate device in programs->utilities->audio/midi setup with your RME device and BlackHole. Name this device Dolby Atmos

Use any routing device (DAW etc) and use your new created aggregate device to route from BlackHole to RME.

@MC you will find a lot informations about the channel irritation of Apple Music app in the Facebook Atmos groups or:

https://www.pro-tools-expert.com/produc … y-hardware

Best regards from Qatar,
Stefan

10 Reply by MC

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Re: Atmos / spacial audio playback on macs

Thanks for the link!

Regards
Matthias Carstens
RME

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  • Registered: 2009-09-15
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Re: Atmos / spacial audio playback on macs

I followed that post on pro-tools-expert as well, it is what got me tinkering with this.

But the author of the article says "I have seen some reports this only works with a 16x16 configuration". That's clearly not the case as I have it working now with a 12 channel config. So the ceiling is 16 channels? As in 9.1.6 perhaps?

It would be nice if RME could look into this since pretty much every RME product exceeds 16 channels. Personally I find Loopback a far more comfortable solution than blackhole as it also does the routing (and much more), but it does cost 100 bucks. Whether or not it's worth that just for this workaround I don't know, but it does do much more.

12 Reply by hselters (edited by hselters 2022-11-10 13:55:34)

  • Registered: 2018-12-21
  • Posts: 264

Re: Atmos / spacial audio playback on macs

I tried setting up Digiface USB and a Fireface UCX as 7.1 Rear Surround and 7.1.4 Atmos Surround Devices in the Audio Midi Setup on macOS Monterey. For some reason I only ever get 5.1 with those, the additional channels do not get recognised by Apple's Music and TV app.

I can confirm it works with 7.1.4 when setting up a virtual soundcard as an Aggregate Device on macOS (I did not use Blackhole but Pro Tools Audio Bridge 16 for that as it was already installed on my Mac).
Of course this comes with the drawback of having a DAW running to send the audio further to the UCX.

I noticed that when I listen to an Atmos file on Apple Music through this setup and switch back to Fireface UCX on the fly, then it maintains the 7.1.4 stream, outputting it directly to the Fireface.
Once I retrigger that file, it jumps back to 5.1

  • Registered: 2009-09-15
  • Posts: 25

Re: Atmos / spacial audio playback on macs

Thanks everybody, good to have options.