Audio Midi Setup for Atmos playback from Music App problem with 16ch limit

[Really Nice Audio]

Does anyone have any audio setup expertise with Dolby Atmos playback.
I use an RME device that shows in the Audio Devices setup as 36 in/36 out. From my understanding when you launch the Music App it checks with the Audio Device that is set to output how many channels its has. And for some reason if it sees more than 16 it reverts to 5.1 instead of 7.1.4
I got around this by using a third party app called Loopback to create a 16 virtual Audio Device.
Oddly if I switch to my RME without closing the Music App it continues to play correctly directly to the hardware, until I relaunch the Music App and it reverts back to 5.1

Here is a video demonstrating the behaviour

 

[broly]

i'll preface my statements by saying by no means am i an expert in your area, nor do i pretend to be.

that being said from my understanding of CoreAudio (i've ported the linux driver for ASUS xonar cards to mac) it's the device that presents its capabilities to the vendor (the program that sends the data to the coreaudio API), which will then send the appropriate stream.

it's possible there's some check where, if there's more than 16 channels, it reverts to 5.1, but i doubt it. there is no material difference from the vendor's point of view. it will try to send a 7.1.4 (12 channel) stream if the device says it can accept 12 channels, but your device does not do that.

looking closer at your configuration in MIDI setup, it seems your RME device is showing 8 channels:

whereas your loopback device is showing 16 (right beside format).

this probably explains the phenomenon you're experiencing.

in-effect, your device states it only supports an 8 channel 32 bit integer stream and that's what APPUL music will see.

so i think APPUL, in this specific context, is right for once: RME is doing something weird with their CoreAudio driver because if it's a true 32 channel device, it should be able to present itself as such to the CoreAudio API (as your loopback device is doing).

surprised you didn't catch this niggle before posting. you did a pretty thorough test.

fyi: if "spatial audio" ever takes off, it won't be on APPUL music. that's just my point of view. the existing SACD/DVD-A stuff is far too valuable to be sold for 1 dollar. i bet the thriller mix is a joke (just my two cents of course).

 

[Really Nice Audio]

i'll preface my statements by saying by no means am i an expert in your area, nor do i pretend to be.

that being said from my understanding of CoreAudio (i've ported the linux driver for ASUS xonar cards to mac) it's the device that presents its capabilities to the vendor (the program that sends the data to the coreaudio API), which will then send the appropriate stream.

it's possible there's some check where, if there's more than 16 channels, it reverts to 5.1, but i doubt it. there is no material difference from the vendor's point of view. it will try to send a 7.1.4 (12 channel) stream if the device says it can accept 12 channels, but your device does not do that.

looking closer at your configuration in MIDI setup, it seems your RME device is showing 8 channels:

View attachment 2205570


whereas your loopback device is showing 16 (right beside format).

View attachment 2205571

this probably explains the phenomenon you're experiencing.

in-effect, your device states it only supports an 8 channel 32 bit integer stream and that's what APPUL music will see.

so i think APPUL, in this specific context, is right for once: RME is doing something weird with their CoreAudio driver because if it's a true 32 channel device, it should be able to present itself as such to the CoreAudio API (as your loopback device is doing).

surprised you didn't catch this niggle before posting. you did a pretty thorough test.

fyi: if "spatial audio" ever takes off, it won't be on APPUL music. that's just my point of view. the existing SACD/DVD-A stuff is far too valuable to be sold for 1 dollar. i bet the thriller mix is a joke (just my two cents of course).

Wow nice attention to detail there!
I was focused on the left hand plane where it shows it is 36 I/O and also when you press configure speakers there are 2 tick boxes that enables 2x 8 streams. But of course this is after that first Stream 1-8 that it declares.
I shall have to jump on the RME forums and see if they are aware of this.
Thanks you for taking an interest in my dilemma! I believe you have shed some light o the matter.

 

[broly]

Wow nice attention to detail there!
I was focused on the left hand plane where it shows it is 36 I/O and also when you press configure speakers there are 2 tick boxes that enables 2x 8 streams. But of course this is after that first Stream 1-8 that it declares.
I shall have to jump on the RME forums and see if they are aware of this.
Thanks you for taking an interest in my dilemma! I believe you have shed some light o the matter.

thanks for bringing your knowledge to this undeserving forum and sharing, what i feel, are "closely guarded" intricacies of the mastering process.

i suspect they know about this but were hoping no one noticed, because lets face it: most people in your line of work don't know their foot from their ass and are not focused on the "next big thing" like you are.

it seems to me, and i could be wrong here, that the hardware itself is 'multiplexed'.

• indeed, i just looked up your card (i was wondering how you had so many channels with optical) and it seems each of those "ADAT" jacks are 8 channels? i thought they would be 18, but i guess the way they count 72 total channels is not solely-based on the "important jacks"

i don't think there is a solution, but again i'd be happy to be wrong. their solution would probably involve some kind of abstraction that hides the physical configuration from the vending program.

• have you tried to create a new, aggregate device in Audio MIDI Setup that involves "joining" the ADACs?
  • i'm not sure if that is possible, since it seems your "configure speakers" option already does something like that, possibly making it difficult to

please do let us know if you get a resolution.

can't wait til it's time to start remastering the "good stuff". that's probably going to buy us time to fill the disappointing void in the music scene. i miss the 09 indie scene. The Enemy (from Coventry) lifted the veil when they quit music for "real jobs".

i'll take The Roses in 5.1, i'm not picky ^_^ imaging the trains from the opening track with more channels!

 

[Really Nice Audio]

I have done a deep dive into the Dirac Multichannel surround processor and they have a similar problem in that their Audio Virtual device is only 8 channels and even that does not work correctly with Apple Music. However if I run it as a plugin in a 7.1.4 compatible DAW I can route things around and now hear room corrected surround. Sounds amazing!!

This works with Apple TV as well

 

[broly]

what an awesome video man.

i forgot to respond when you first posted, as i watched it right when i got the notification.

thanks for sharing this knowledge.

i had no idea that logic pro allowed you to merge two separate hardware interfaces to appear as a separate interface. that's cool.

also with respect to your first video (your demonstration starting at 5:13ish), i forgot to ask if you double-checked whether the reydat card was actually outputting the atmos sound after you "tricked" apple music by first selecting/outputting from the loopback interface.

• isn't it possible that since your speakers are the output for different devices, that the atmos output was actually from your loopback device and simply *appeared* to be from your reydat?

 

[Really Nice Audio]

what an awesome video man.

i forgot to respond when you first posted, as i watched it right when i got the notification.

thanks for sharing this knowledge.

i had no idea that logic pro allowed you to merge two separate hardware interfaces to appear as a separate interface. that's cool.

also with respect to your first video (your demonstration starting at 5:13ish), i forgot to ask if you double-checked whether the reydat card was actually outputting the atmos sound after you "tricked" apple music by first selecting/outputting from the loopback interface.

• isn't it possible that since your speakers are the output for different devices, that the atmos output was actually from your loopback device and simply *appeared* to be from your reydat?

Yes the RME did output sound when I tricked it!! Weird or what?

 

[broly]

Yes the RME did output sound when I tricked it!! Weird or what?

was your loopback device created in logic pro? what was it, exactly? a combination of the two 8-channel ADATs? when i first watched your video i assumed the loopback device was a completely separate interface from the RME, but after watching your second video i suspect it's simply an abstraction for your RME device.

either way, yes, it's weird. but then again the OS won't multiplex two 8 channel hardware interfaces by itself, so the loopback (if it indeed is a combination of the two ADAT interfaces) is probably the best (and only) solution.

edit: and why do they call it "ADAT"? it's not like they're doing anything other than using the bandwidth of the 2.1 optical stream, no different than dolby or DTS, but i assume it's a standard in the music business? it's weird seeing a standardised interface/port being called something different from the industry term.

 

[Really Nice Audio]

No loopback is a separate program that makes virtual audio device and allows me to route directly to the RME in my desired order.

Loopback - Cable-free audio routing for Mac

Get all the power of a high-end studio mixing board, right inside your Mac!

rogueamoeba.com

ADAT originally came from the original Alesis they made for their 8 track digital format and is actually 8 channels per port.
I have really enjoyed watching 'See' and 'Silo' on Apple TV+ in 7.1.4!

 

[broly]

regarding the loopback interface creation: that makes sense.

about the ADAT optical port: https://en.wikipedia.org/wiki/TOSLINK

ADAT Lightpipe or simply ADAT Optical uses an optical transmission system similar to TOSLINK, and is used in the professional music/audio industry. While the ADAT Lightpipe format uses the same JIS F05 connectors as TOSLINK, the ADAT Lightpipe data format is not compatible with S/PDIF.[citation needed]

in my opinion, i am betting this ADAT format relies heavily on the specification of TOSLINK. there is no way they are using something that "looks similar, but isn't". the costs would be prohibitive to do something like that, AND, as we have seen in your instance alone: many licensees of ADAT technology are simply too stingy to produce proper drivers (seems to be a trend!).

re: movies in atmos: delighted to hear you're reveling in 7.1.4. i haven't yet heard anything in atmos and tbh i'll be happy with 5.1 music being adopted more readily. whether that will happen is an open question, but in my opinion we're two decades late and it's the only way forward for proper monetisation of musicianship.

SACD had many things right, if you ask me. medium offered reasonable protection from theft, playback required a device with specific support, and even if you ripped the data you still needed a few things (speakers, decoding, etc) that went above the typical napster pirate.

the ABKCO stones stuff is top notch.