How does Atmos on Apple headphones actually work?

[V96GLF]

I see the new Apple “AirPod max” headphones claim to support Atmos, assumedly using Apple’s version of binaural processing. They look to be quite impressive as headphones, but let’s wait for some reviews before deciding.

What I don’t understand is how one is supposed to get Atmos content onto the things, other than iPad or iPhone streaming - which doesn’t really interest me. If I have a music blu-ray with Atmos (I have several), how would I go about playing that on Apple (or anyone else’s) headphones?

 

[kap'n krunch]

This is not a contest , so I usually look for started threads, which I did an hour before you did... I don´t care which one stays, I just like to keep the forum a bit more organized...

 

[V96GLF]

This is not a contest , so I usually look for started threads, which I did an hour before you did... I don´t care which one stays, I just like to keep the forum a bit more organized...

Hah - yes - I did search before posting, but only in the Atmos sub-forum. Actually I don’t see any harm in keeping both threads, with the Atmos comments here and the more general hardware comments in the other thread.

 

[Strilo]

How does Atmos work on a soundbar? I think there's a discussion to be had about this idea (ridiculous in my opinion) that Atmos does anything meaningful in anything less than a 5.1.2 system...

Change my mind!

 

[jimfisheye]

That's my worry with these new 3D formats too. Buzzword like association with cheapness products like soundbars and now ratty cheap headphones marketed like jewelry with no ability to even deliver stereo sound that isn't garbled. Not a good look. And then at the same time restricting the playback codec to hardware AVR products as a form of copy protection. These formats are destined to be a buzzword for cheesy movie soundtrack sound and nothing more. Not happy to see how this is devolving one little bit!

The EFI firmware bug introduced in the 10.15.7 update (and continuing into the OS XI introduction) that can brick your Mac isn't a very good look for Apple right now either, but I digress.
(Not to be confused with the T2 chip bug in the 10.15.4 update that only affects some post Jobs Macs. That wasn't a good look either but it was only post-Jobs machines affected.)

 

[furui_suterioo]

Dolby Atmos for headphones on windows 10 actually costs money but there is a free trial, I watched some of the movie trailers using Sony MDR-V6 headphones and JVC 5944 quadphones, turning the Atmos setting on and off, barely could any difference(if there really was any).
I know I keep repeating myself and rambling on about quadphones, but I've been having too much fun re-listening to everything lately ever since I got adapters allowing me to switch around the 4 inputs from the double stereo Y-splitter. Sometimes I listen with, for example, left in the front drivers, right in the rear drivers(which remain in phase-reverse all the time), then rotate the inputs listen again, and again and so forth in all possible different directions/configurations which 4 drivers can allow. This octopus of adapters with the quadphones continues to reveal hidden surprises in material that I thought I knew every note of, there aren't any modern headphones which can do this, I suppose there aren't enough potential consumers like myself(who are obsessed with insanity), to justify. My Atmos for headphones trial ran out before the adapters came so I didn't get to test it in non-standard configurations, the same goes for the version of "Atmos" on my android phone, crAPMOS.

 

[kap'n krunch]

where does it state anything about Dolby Atmos on the release notes? cause I would have definitely have posted my thread on the Atmos section if I had seen it...

 

[V96GLF]

where does it state anything about Dolby Atmos on the release notes? cause I would have definitely have posted my thread on the Atmos section if I had seen it...

Interesting. Here’s where I saw it mentioned, but perhaps this source is incorrect?

https://www.cultofmac.com/722648/airpods-max-launch-apple-over-ear-headphones/

 

[kap'n krunch]

Interesting. Here’s where I saw it mentioned, but perhaps this source is incorrect?

https://www.cultofmac.com/722648/airpods-max-launch-apple-over-ear-headphones/

Oh, I just saw it...interesting... no mention of it on the apple release though...afaik, headphones have a very rough time simulating surround-which is on "ground level" so it'd be interesting to know how they might try to simulate "height speakers"...

 

[V96GLF]

Oh, I just saw it...interesting... no mention of it on the apple release though...afaik, headphones have a very rough time simulating surround-which is on "ground level" so it'd be interesting to know how they might try to simulate "height speakers"...

Look again:

Spatial Audio: AirPods Max use spatial audio with dynamic head tracking to place sounds virtually anywhere in a space — delivering an immersive, theaterlike experience for content recorded in 5.1, 7.1, and Dolby Atmos

 

[kap'n krunch]

Look again:

Hmmm I don't think you are aware of the fact that the blue text is a link to another page..and if you are , then I do not understand your last post.

 

[V96GLF]

Hmmm I don't think you are aware of the fact that the blue text is a link to another page..and if you are , then I do not understand your last post.

Yes, I have followed your link to the Apple announcement, and the above quote is copy-and-paste from it.

 

[gwlbe]

I assume the Air Pods Max "pay thru the nose/ears" work similar to the Air Pods Pro (APP) with the spatial sound. I can't speak for Atmos, but converted FLAC MCH to a *.mp4 container with ac3 5.1 has an ambient sound with APP, not discrete but close. I enjoy it enough that I have started down the rabbit hole to converting/duplicating my FLAC MCH collection to MP4 which i will put on my Iphone 11 max as Music Videos. Unless you are captive to the IOS environment for Iphone - iPad its not worth pursuing. The requirements are that you need IOS 14 on recent Apple devices. "Works with AirPods Pro. Requires iPhone 7, iPhone 7 Plus, iPhone 8, iPhone 8 Plus, iPhone X, iPhone XS, iPhone XS Max, iPhone XR, iPhone 11, iPhone 11 Pro, iPhone 11 Pro Max and iPhone SE (2nd generation)."
BTW I'm a Windows user that by passed the Blackberry to the original Iphone. Never went Android.

Here are a couple links that I used to education myself.

https://medium.com/@d.ben158/music-...und-music-to-spatial-audio-music-a342191cecb4
I use the following FFmpeg CMD :
ffmpeg for %i in (*.flac) do ffmpeg -i "%i" -loop 1 -i folder.jpg -map 1:v -map 0:a -c:a ac3 -b:a 640K -pix_fmt yuv420p -c:v libx264 -shortest -fflags +shortest -max_interleave_delta 100M "%~ni.mp4"

https://forums.macrumors.com/threads/list-of-apps-that-work-with-spatial-audio.2255160/

 

[V96GLF]

Thanks for those links - very interesting.

I am 90% Apple, apart from a Windows gaming PC and a Pi or two.

Actually I’m not too bothered about 5.1 material, as I have a decent conventional surround setup. It just bothers me that I have several Atmos blu-rays that I can’t take advantage of!

Yes, the Apple headphones are expensive compared to other headphones, but they cost far less than upgrading a 5.1 system to Atmos! It’s all academic anyway... as I’m not queuing up to purchase the things.

 

[jonfo]

I got my Airpods Max two days ago, and Spatial Audio is amazing on these things.

For context: I have a Smyth Realiser A16 Atmos headphone processor ($4K) and several cans, including electrostatic. Also, have a custom home theater room with a 5.4.4 with 5 electrostats and 4x JBL SCS8 (commercial cinema stuff) for overheads. Marantz AV8802 processor driving 18 channels of amplification (active XOs on most channels). Also have a secondary media system with a 5.4.2 (yes, four small subs, it's square room) the 'overheads are Elac elevation modules. So three current Atmos systems, and have been eagerly awaiting the Max's arrival.

So far, incredibly impressed with spatial audio considering the HRTF is somewhat generic. The custom HRTF one creates with the A16 allows much more discrete positional accuracy of the rendering. But the Airpods are as good as the default HRTF in the A16,. Not sure, but they could be calculating the actual width of the wearers face (based on delay metrics from H1 to H1 in each ear).

The head tracking is pretty good, but I still need to spend more time comparing it to the A16's tracker.

Audio quality of the Max is very good, I can listen to music for hours with no complaints. Not quite as good as a couple of my other cans, but each of those cost as much or more than the Max.

The ANC feature is extremely effective, but it has a high noise floor one can hear at low volumes and unfortunately, is not defeatable (yet).

Remixing current Atmos music rips to mp4 is a pain, and the quality compromised but allows testing Spatial Audio from the iPad and iPhone. The rendering o the Max is very cool.

So based on their ANC performance, basic audio quality, these are good headsets but add in the spatial audio feature, and they are a good value.

 

[jonfo]

To answer the OP's question in more detail, here is my guess:

The heavy lifting is performed on the iOS to TVOS device, where a Dolby Digital+ decoder handles the encoded stream and decodes the base channels plus objects, rendering them into a 3D binaural output using a generic HRTF (hopefully modified by actual users inter-aural distance). The rendering takes into account the positional feedback from the Airpods relative to the renderers position to provide the 'anchoring' of the audio.

This is pretty much what the Realiser A16 does (except it handles full-rez TruHD Atmos as well) if using the supplied default HRTF.

I have a music blu-ray with Atmos (I have several), how would I go about playing that on Apple (or anyone else’s) headphones?

For now, you rip, transcode to DDP in an .MP4 container, and copy that to your iPad. See Music for Airpods: How to Convert Existing Surround Music to Spatial Audio Music


Longer-term, I expect Apple to release a box with the following:
- Multiple (6 to 8) HDMI inputs,
- Two HDMI outs, one of which supports eARC so TV apps can provide streams and one with video and audio to feed receivers
- Support for 4 concurrent Spatial Audio capable clients
- Ability to drive 4 or 5 HomePods as a surround setup (they have a patent to this effect).

A feature I hope they add but doubt it, is to have a 'sub out' that is engaged during spatial audio to drive a tactile transducer or something like a SubPac (I have one and it's great). And have it dynamically adjust the delay based on the distance of the Airpods from the ATV.

The above would be the perfect solution for apartments and places where deploying a full-blown stereo is not possible, as this plus a couple of HomePods would allow for a decent music system, and a killer immersive audio setup when used with AirPods Pro or Max. They could call it the Pod-Caster

 

[V96GLF]

Thanks for the follow-ups, jonfo. Very interesting info. For now I’m not tempted, but perhaps one day if/when it gets a bit more mature.

 

[MidiMagic]

So how do they make you hear atmos on headphones?

 

[V96GLF]

So how do they make you hear atmos on headphones?

By converting it to a binaural simulation, plus head-tracking.

 

[zeerround]

By converting it to a binaural simulation, plus head-tracking.

Is there head tracking? I think that is critical, but I haven't seen anything about atmos for headphones and head tracking.