Billboard on Dolby Atmos

[Franck]

Kristin Robinson from Billboard is asking for Apple listeners feedback on Dolby Atmos
https://www.tiktok.com/t/ZTYaeq4UG/

 

[ar surround]

Interesting. I often wonder how Dolby Atmos played through head phones could sound better than a good stereo mix played through headphones. To be more specific, I find listening to stereo through headphones very enveloping and wonder if the Dolby Atmos mix is actually that much better. Has anyone tried it?

 

[Franck]

Interesting. I often wonder how Dolby Atmos played through head phones could sound better than a good stereo mix played through headphones. To be more specific, I find listening to stereo through headphones very enveloping and wonder if the Dolby Atmos mix is actually that much better. Has anyone tried it?

The goal is not to be better, but to be spatial, like if you were in the room with all those speakers.

 

[jimfisheye]

Interesting. I often wonder how Dolby Atmos played through head phones could sound better than a good stereo mix played through headphones. To be more specific, I find listening to stereo through headphones very enveloping and wonder if the Dolby Atmos mix is actually that much better. Has anyone tried it?

It usually doesn't! It's a roll of the dice. Sometimes a surround mix folded down to stereo ends up with something going on that makes it a little more interesting than the dedicated stereo mix. Just like sometimes an algorithm driven upmix can hit a mark. Usually both go the other way. The dedicated stereo mix sounds better than a surround mix folded down and the stereo original sounds better than an upmix generated from it.

Atmos first and foremost is a hardware dongle that forces the consumer to buy a new AVR or other Atmos decoder equipped device to listen to the content in any form. Stereo earbuds, soundbar... doesn't matter. They accomplished that. I suppose we should celebrate that someone found a way to make 12 channel surround mixes tag along and they haven't broken that yet!

Binaural is not surround sound! Interacting with surround sound in a space is a more complex event. People are in fact working on making head tracking work to try to introduce this as a binaural option for headphones! It's not lost on anyone and it's absolutely a goal. It's just kind of "video game" crude at present. And a lot of this is all still aimed at movie soundtracks. Our music surround sound niche is already lost on them!

That's what I think I'm seeing and hearing anyway. If someone has a binaural system with head tracking that delivers artifact free high resolution lossless sound, bring it! The industry is still struggling with noise cancelling headphones. (Again, for any fidelity beyond computer gaming or online streaming.) Something isn't fast enough yet to manhandle all that processing in real time for full audio. It would be a lot! Every slight motion of your head translated and the entire sound array recalculated every microsecond. Keeping a full audio band and no artifacts!

 

[Franck]

It usually doesn't! It's a roll of the dice. Sometimes a surround mix folded down to stereo ends up with something going on that makes it a little more interesting than the dedicated stereo mix. Just like sometimes an algorithm driven upmix can hit a mark. Usually both go the other way. The dedicated stereo mix sounds better than a surround mix folded down and the stereo original sounds better than an upmix generated from it.

Atmos first and foremost is a hardware dongle that forces the consumer to buy a new AVR or other Atmos decoder equipped device to listen to the content in any form. Stereo earbuds, soundbar... doesn't matter. They accomplished that. I suppose we should celebrate that someone found a way to make 12 channel surround mixes tag along and they haven't broken that yet!

Binaural is not surround sound! Interacting with surround sound in a space is a more complex event. People are in fact working on making head tracking work to try to introduce this as a binaural option for headphones! It's not lost on anyone and it's absolutely a goal. It's just kind of "video game" crude at present. And a lot of this is all still aimed at movie soundtracks. Our music surround sound niche is already lost on them!

That's what I think I'm seeing and hearing anyway. If someone has a binaural system with head tracking that delivers artifact free high resolution lossless sound, bring it! The industry is still struggling with noise cancelling headphones. (Again, for any fidelity beyond computer gaming or online streaming.) Something isn't fast enough yet to manhandle all that processing in real time for full audio. It would be a lot! Every slight motion of your head translated and the entire sound array recalculated every microsecond. Keeping a full audio band and no artifacts!

I agree, getting a stereo mix from the atmos file, will not be as good as making a stereo mix from the stems.

So now, it is all about making a binaural version, that makes it sounds like you are not wearing headphones.

Apple has been working on reducing the bluetooth latency, so they can send the head position via bluetooth, have the iphone render the 2 channels binaural and send them to the airpods.

They have also introduced customized "HRTF": take a lidar video of your head to calculate a better binaural experience.

Dolby "recently" introduced head tracking, after Apple did. Some head tracking headsets work with the Dolby Atmos Renderer.

There is still some work to have a good binaural experience, and yes it has been driven by games. You need to know when someone is in your back However if you want to customize a virtual environment (Vision Pro, Quest), you need to solve this audio problem.

 

[barfle]

There’s a device out there called a Smythe Realizer (IIRC) that supposedly does a pretty good job of folding down Mch stuff to headphones, although it takes “training” with your head and ears to process the signals accordingly. All our ears are unique, so I’d be skeptical of many of these claims of atmos effects being audible through headphones.

I don’t use ‘phones very much, mostly when it’s noisy, so it’s not a high priority for me to get spatial audio without a roomfull of speakers. But who knows, I might live long enough that I need another project.

 

[zdjh22]

There’s a device out there called a Smythe Realizer (IIRC) that supposedly does a pretty good job of folding down Mch stuff to headphones, although it takes “training” with your head and ears to process the signals accordingly. All our ears are unique, so I’d be skeptical of many of these claims of atmos effects being audible through headphones.

I don’t use ‘phones very much, mostly when it’s noisy, so it’s not a high priority for me to get spatial audio without a roomfull of speakers. But who knows, I might live long enough that I need another project.

Yes, the Smyth Realizer A16. I have one.

You’d don’t necessarily have to train with your head, but it is very necessary to equalize your choice of headphones with either their tiny ear canal microphones, or via a manual procedure (“MANLOUD”) where you tediously listen and adjust levels across the spectrum. These procedures produce what they call an HPEQ, which indeed is unique to you and the particular model of headphone.

The training also involves using the in-ear canal microphones, and it produces what they call a PRIR. A PRIR is a combination (convolution?) of your personal HRTF and the room’s binaural impulse response (BRIR), and it involves a frequency sweep measurement for each loudspeaker with the head in at least three positions. The process for making your own is pretty involved. There is a commercial house that sells PRIRs, and if they are a good match to your HRTF (your head and ear shape), they are nearly as good as your own personally measured PRIR. Perhaps even better, since they were produced in a good acoustic environment with a variety of very high quality speaker models with precision angles.

Very much like Impulcifer, if you’ve tried it, there is a considerable “WOW” factor with an A16. I’ve done many of my own personal PRIR measurements of my listening room (7.1.2), and the sound while wearing headphones exactly matches the sound without. As in, a complete out-of-head experience, with my room speakers appearing (sound wise) to be in the exact same position in the headphones as in the physical room. YMMV of course. The A16 does have head tracking, and that does help. I’ve also measured my physical speakers at a variety of azimuth and elevation angles, so have for example Atmos virtual sound rooms up to 10.1.6 (and higher speaker counts with the commercial PRIRs). The commercial PRIRs work very well for me.

I have the new Apple AirPods (the in-ear, not the over-ear) and they are reasonably effective for me for listening to Atmos. The head tracking effect is not as strong as with the A16. Also, the overhead virtual speakers in the A16 for me are, well, overhead. In Auro-3D, the “voice of god” speaker is directly over my head (using a commercial PRIR). For me the 3D experience with Apple AirPods and Atmos is more planar, but definitely spatial - overhead speakers don’t really sound very elevated, and much less localized than with the A16.

Measuring your personal HRTF with the AirPods is easy, asumming you have an newish iPhone or iPod with the 3D camera (for facial recognition), and it does improve the experience. You can also now do a hearing test (yes, “beep beep beep” over and over), and a tailored response curve can subsequently be applied to your listening. That helps with my left ear’s tinnitus. The HPEQ in an A16 with MANLOUD does the same type of correction.

For me, both the Apple AirPods and the A16 greatly enhance my enjoyment of music. Of course, Apple Atmos Music is lossy, and I can tell the difference between that and physical media with TrueHD lossless (the lossy is a bit “thinner”). Also, you are very much limited in what media you can listen to with AirPods (nothing beyond DD+, so forget about TrueHD Atmos from a BluRay).

An A16 is pricey, but on the other hand, assembling a good acoustic space with 10.1.6 Atmos or 13.1 Auro-3D or 7.1.4 DTS:X from scratch is much more expensive, and requires a suitable room. The A16 is the apartment dweller’s dream for music and movie lovers. Although I watch movies/TV and listen with my physical speakers, I prefer the A16 for music. I love being able to tailor my listening room for the source; for example, a true quad room with large virtual speakers in the corners for quad recordings. I’m not really willing or able to replicate that experience by moving physical speakers about. Further, you’ve got to experience Ziggy Stardust in 10.1.6 or 13.1.8 to see what Atmos can really do.

As to an earlier claim to the contrary, yes, binaural can be surround! Your ears are point source receivers with some additional structure (head shape and ear shape affect time and loudness queues, reflections within your ears’ pinna are important, for some frequencies the resonances within the ear canal are important), but except for deep canal resonances, with a personal PRIR the sound patterns - intensity and phase - from a real room can be replicated with headphones using a binaural processor. If you want to read about the science, math, and physiological measurements behind all of this, a good resources is Bosun Xie’s tome “Spatial Sound, Principles and Applications” (CRC Press), 800+ pages. Or his textbook, “Head-Related Transfer Function and Virtual Auditory Display” (J. Ross Publications), ~500 pages. For a much smaller investment than a Realizer (money wise, not time wise), you can use Impulcifer (plus HeSuVi and something else I forget now) and roll your own 7.1 binaural system, just not Atmos.

 

[MidiMagic]

Interesting. I often wonder how Dolby Atmos played through head phones could sound better than a good stereo mix played through headphones. To be more specific, I find listening to stereo through headphones very enveloping and wonder if the Dolby Atmos mix is actually that much better. Has anyone tried it?

How do you do it?

 

[kfbkfb]

https://www.worldradiohistory.com/A...idelity/70s/High-Fidelity-1976-08.pdf#page=36

Run the Atmos surround mix (downmixed - for example 7.1.4 - 7 channels mapped to quad [real and phantom locations] & 4 overhead channels also mapped to quad [front left overhead would be mostly in LF with a little in RF,LB,RB etc.] through an SQ matrix quadraphonic encoder to get "stereo" and listen with regular stereo headphones...

I don't recall anyone creating an SQ encoded surround sound test sequence and then listening through good quality stereo headphones, I'm interested to know if the SQ encoded "quad" sound locations are identifiable listening with stereo headphones.


Kirk Bayne

 

[ar surround]

How do you do it?

No idea.

 

[barfle]

Yes, the Smyth Realizer A16. I have one.

You’d don’t necessarily have to train with your head, but it is very necessary to equalize your choice of headphones with either their tiny ear canal microphones, or via a manual procedure (“MANLOUD”) where you tediously listen and adjust levels across the spectrum. These procedures produce what they call an HPEQ, which indeed is unique to you and the particular model of headphone.

The training also involves using the in-ear canal microphones, and it produces what they call a PRIR. A PRIR is a combination (convolution?) of your personal HRTF and the room’s binaural impulse response (BRIR), and it involves a frequency sweep measurement for each loudspeaker with the head in at least three positions. The process for making your own is pretty involved. There is a commercial house that sells PRIRs, and if they are a good match to your HRTF (your head and ear shape), they are nearly as good as your own personally measured PRIR. Perhaps even better, since they were produced in a good acoustic environment with a variety of very high quality speaker models with precision angles.

Very much like Impulcifer, if you’ve tried it, there is a considerable “WOW” factor with an A16. I’ve done many of my own personal PRIR measurements of my listening room (7.1.2), and the sound while wearing headphones exactly matches the sound without. As in, a complete out-of-head experience, with my room speakers appearing (sound wise) to be in the exact same position in the headphones as in the physical room. YMMV of course. The A16 does have head tracking, and that does help. I’ve also measured my physical speakers at a variety of azimuth and elevation angles, so have for example Atmos virtual sound rooms up to 10.1.6 (and higher speaker counts with the commercial PRIRs). The commercial PRIRs work very well for me.

I have the new Apple AirPods (the in-ear, not the over-ear) and they are reasonably effective for me for listening to Atmos. The head tracking effect is not as strong as with the A16. Also, the overhead virtual speakers in the A16 for me are, well, overhead. In Auro-3D, the “voice of god” speaker is directly over my head (using a commercial PRIR). For me the 3D experience with Apple AirPods and Atmos is more planar, but definitely spatial - overhead speakers don’t really sound very elevated, and much less localized than with the A16.

Measuring your personal HRTF with the AirPods is easy, asumming you have an newish iPhone or iPod with the 3D camera (for facial recognition), and it does improve the experience. You can also now do a hearing test (yes, “beep beep beep” over and over), and a tailored response curve can subsequently be applied to your listening. That helps with my left ear’s tinnitus. The HPEQ in an A16 with MANLOUD does the same type of correction.

For me, both the Apple AirPods and the A16 greatly enhance my enjoyment of music. Of course, Apple Atmos Music is lossy, and I can tell the difference between that and physical media with TrueHD lossless (the lossy is a bit “thinner”). Also, you are very much limited in what media you can listen to with AirPods (nothing beyond DD+, so forget about TrueHD Atmos from a BluRay).

An A16 is pricey, but on the other hand, assembling a good acoustic space with 10.1.6 Atmos or 13.1 Auro-3D or 7.1.4 DTS:X from scratch is much more expensive, and requires a suitable room. The A16 is the apartment dweller’s dream for music and movie lovers. Although I watch movies/TV and listen with my physical speakers, I prefer the A16 for music. I love being able to tailor my listening room for the source; for example, a true quad room with large virtual speakers in the corners for quad recordings. I’m not really willing or able to replicate that experience by moving physical speakers about. Further, you’ve got to experience Ziggy Stardust in 10.1.6 or 13.1.8 to see what Atmos can really do.

As to an earlier claim to the contrary, yes, binaural can be surround! Your ears are point source receivers with some additional structure (head shape and ear shape affect time and loudness queues, reflections within your ears’ pinna are important, for some frequencies the resonances within the ear canal are important), but except for deep canal resonances, with a personal PRIR the sound patterns - intensity and phase - from a real room can be replicated with headphones using a binaural processor. If you want to read about the science, math, and physiological measurements behind all of this, a good resources is Bosun Xie’s tome “Spatial Sound, Principles and Applications” (CRC Press), 800+ pages. Or his textbook, “Head-Related Transfer Function and Virtual Auditory Display” (J. Ross Publications), ~500 pages. For a much smaller investment than a Realizer (money wise, not time wise), you can use Impulcifer (plus HeSuVi and something else I forget now) and roll your own 7.1 binaural system, just not Atmos.

I have to admit, if I was ever in the same room with one, it had to be at a trade show. I have never tried one, but I’ve read and heard about them, and that once you’ve gone through all the setup it requires, it’s remarkable. But as you noted, it requires a lot of personalization to fully realize the realizer (sorry, it’s still early). So it seems like it would take a similar amount of personalization to get an atmos effect from headphones. My Atmos system is still under construction, and with my other projects, I might have it going by Christmas. I’ll hold off on any condemnation of “headphone atmos” until I’ve actually tried it, but I’m skeptical.

By the way, I’m always interested in what sort of “special” gear we might have in our systems. The Smyth is one of those. I believe someone here has a Trinnov pre-pro, and I know of a 3D projector or two.

 

[austinsignal]

Another option for better headphone listening to ATMOS is APL's Virtuoso. Designed to emulate full speaker surround rigs for headphone mixing. Definitely not a toy piece of software it does a really nice job. Lots of headphone profiles,, and a number of speaker/room profiles. You can profile your own room too if you're looking to reproduce it sonically. For recreational listening it sounds better than Apple's Spatial or Dolby Binaural....maybe a harbinger of things to come sonically.

Also, regarding hearing differences (better/worse) between Dolby Binaural, stereo master, and Apple Spatial. There are now tools like Ginger Sphere and Audio Movers out there that allow for immediate A/B/C comparisions. Incredibly useful when mixing, and does allow one to evaluate the surround headphone formats. As one who spends an inordinate amount of time doing this A/B/C thing - IMHO when mixes are done well, the BIN and Spatial formats sound great - better than the stereo original. On other forums, some people refer to this as 'super stereo'. To me, Apple's Spatial is more surround-y - kinda wraps around your neck...and rightly or wrongly it also has a little smile eq curve applied to it (Apple's doing) which gives it a little bump on top and the bottom. Kinda like the old 'loudness' button. The Dolby Binaural is not quite as wide as Spatial. But when mixing, I usually bounce back and forth between speakers and headphones with Dolby Binaural playing in the beginning. Towards the end of that effort, I begin adjusting the Object distance settings (each object and/or object pair can be set to Near/Mid/Far), and it all comes to life on headphones. The result is very nice definition of all the objects...and when A/B's with the stereo master, it's usually no contest. At least to me.

 

[zdjh22]

I have to admit, if I was ever in the same room with one, it had to be at a trade show. I have never tried one, but I’ve read and heard about them, and that once you’ve gone through all the setup it requires, it’s remarkable. But as you noted, it requires a lot of personalization to fully realize the realizer (sorry, it’s still early). So it seems like it would take a similar amount of personalization to get an atmos effect from headphones. My Atmos system is still under construction, and with my other projects, I might have it going by Christmas. I’ll hold off on any condemnation of “headphone atmos” until I’ve actually tried it, but I’m skeptical.

By the way, I’m always interested in what sort of “special” gear we might have in our systems. The Smyth is one of those. I believe someone here has a Trinnov pre-pro, and I know of a 3D projector or two.

Anyone here with a Monoprice HTP-1 pre-pro?

Also, anyone here with an Auro-3D decoding AVR? I’m trying to find out whether the Diabolo BluRay has a faulty Auro-3D track. A couple of us with A16’s can’t get it to decode. It will only upmix (“Auromatic”) for us. The HTP-1 has the same decoder (Momentum Data Systems APM-117) as the A16 so it might have the same Diabolo issue.

As to non-Realizer (or Virtuoso or Impulcifer) surround sound on headphones, a pair of AirPods and an Apple Music account, assuming you have a Mac, iPhone, or iPad, are a very inexpensive way to get a more than reasonable taste of spatial audio. As noted on other similar threads here, it’s a good guess that by far headphone / earbud users are the largest group of Atmos consumers. It’s certainly not the same experience as a physical system or one of the professional binaural rendering systems, but IMO they can definitely enhance your listening experience. My go to audio system for endless snow shoveling in the winter at 10,000 feet.

 

[zdjh22]

Another option for better headphone listening to ATMOS is APL's Virtuoso. Designed to emulate full speaker surround rigs for headphone mixing. Definitely not a toy piece of software it does a really nice job. Lots of headphone profiles,, and a number of speaker/room profiles. You can profile your own room too if you're looking to reproduce it sonically. For recreational listening it sounds better than Apple's Spatial or Dolby Binaural....maybe a harbinger of things to come sonically.

Also, regarding hearing differences (better/worse) between Dolby Binaural, stereo master, and Apple Spatial. There are now tools like Ginger Sphere and Audio Movers out there that allow for immediate A/B/C comparisions. Incredibly useful when mixing, and does allow one to evaluate the surround headphone formats. As one who spends an inordinate amount of time doing this A/B/C thing - IMHO when mixes are done well, the BIN and Spatial formats sound great - better than the stereo original. On other forums, some people refer to this as 'super stereo'. To me, Apple's Spatial is more surround-y - kinda wraps around your neck...and rightly or wrongly it also has a little smile eq curve applied to it (Apple's doing) which gives it a little bump on top and the bottom. Kinda like the old 'loudness' button. The Dolby Binaural is not quite as wide as Spatial. But when mixing, I usually bounce back and forth between speakers and headphones with Dolby Binaural playing in the beginning. Towards the end of that effort, I begin adjusting the Object distance settings (each object and/or object pair can be set to Near/Mid/Far), and it all comes to life on headphones. The result is very nice definition of all the objects...and when A/B's with the stereo master, it's usually no contest. At least to me.

I’ll second the Virtuoso recommendation. When my A16 had to go back for repairs, I used Virtuoso to tide me over. Michael Wagner’s YouTube videos helped a lot with the fiddly details to get it working.

Virtuoso also has head tracker support, plus support for importing your personal HRTF if you’ve arranged to have it measured. Works great for listening to Apple Music ATMOS tracks using the built-in OSX Atmos renderer (only up to 7.1.4). Works well on Windows too, although for listening to Atmos you need the DRP or the equivalent.

As noted, Virtuoso is really meant as a tool for monitoring during mixing. Likewise for the Realizer. There’s a lower-cost version of the Realizer specifically for monitoring only that doesn’t have a decoder (Dolby/Auro-3D/DTS) or HDMI, but it has all of the hardware and software for playing virtual speakers via headphones. It has a 16-channel Dante interface.

 

[asibbald]

There’s a device out there called a Smythe Realizer (IIRC) that supposedly does a pretty good job of folding down Mch stuff to headphones, although it takes “training” with your head and ears to process the signals accordingly. All our ears are unique, so I’d be skeptical of many of these claims of atmos effects being audible through headphones.

I don’t use ‘phones very much, mostly when it’s noisy, so it’s not a high priority for me to get spatial audio without a roomfull of speakers. But who knows, I might live long enough that I need another project.

I have a Smyth Realiser A16. I'm pretty sure it's the only device on the market which can achieve fully immersive sound i.e. indistinguishable from listening to the same thing through a full Atmos speaker setup.

I hope the likes of Apple manage to achieve something similar one day - but I suspect it's still many years away.

Not only are we all different physiologically, with different shapes and sizes of heads and ears, it appears we all have different sensitivities to how accurate the illusion needs to be before we accept it as "real". I unfortunately seem to be in the very sensitive group. I need a very accurate reproduction through the headphones - with full head tracking and my own personalised HRTF.

Once I have that however - which is not that hard to do with the Realiser - the illusion is complete. It is near impossible to distinguish between listening on the headphones vs on the loudspeakers, with the exception of very low frequency bass - headphones can't reproduce the physicality of a really good sub.

You may be lucky and not be one of the hyper-sensitive group as I am - in which case, what Apple and others are doing may be quite convincing for you.

But I doubt any of them can produce as realistic an illusion as the Realiser does, irrespective of one's sensitivity level.

 

[Franck]

I have a Smyth Realiser A16. I'm pretty sure it's the only device on the market which can achieve fully immersive sound i.e. indistinguishable from listening to the same thing through a full Atmos speaker setup.

I hope the likes of Apple manage to achieve something similar one day - but I suspect it's still many years away.

I'm looking at the Apple developer documentation and it seems HRTF is possible. It would be great if you could import your own HRTF to work with the airpods. You could then schedule a session to get your HRTF using a Realiser (for a fee).
There is also a need for quicktime to understand Atmos mp4 files.

 

[asibbald]

I'm looking at the Apple developer documentation and it seems HRTF is possible. It would be great if you could import your own HRTF to work with the airpods. You could then schedule a session to get your HRTF using a Realiser (for a fee).
There is also a need for quicktime to understand Atmos mp4 files.

Franck,

Apple must already be able to use HRTFs - and to modify them appropriately with head movement to do what they do. I don't think they allow import of HRTFs created outside the Apple ecosystem though.

You don't need a Realiser to create your own HRTF. In fact, if you use one to create an HRTF, or PRIR as Smyth terms it, you'll not be able to use it outside the Smythe environment.

There are many ways of creating HRTFs. The Industry standard for storing such HRTFs (and other related data) is a file format called SOFA. One tool for creating them is produced by the same lab that produces Virtuoso. The tool is called HAART. I have no experience of it. I'm sure there are many others.

https://apl-hud.com/resources/

 

[zdjh22]

I'm looking at the Apple developer documentation and it seems HRTF is possible. It would be great if you could import your own HRTF to work with the airpods. You could then schedule a session to get your HRTF using a Realiser (for a fee).
There is also a need for quicktime to understand Atmos mp4 files.

Does the documentation talk about the personalization for AirPods that you use an iPhone measurement with the 3D face recognition camera to produce? I know the mesh2hrtf folks support acquisition using an iPhone (IIRC a slightly older model than current is better for some reason), but the process is much more involved than the 30 seconds required with the Apple procedure. I’m also curious whether the Apple HRTF or pseudo-HRTF can be exported, say in a SOFA-format file.

I’m pretty sure that very high quality HRTFs really require a physical measurement in anechoic conditions with the source emitter swept in frequency and through a large variety of positions relative to your head. The optical process that Apple uses, and similarly that of Genelec (Aural ID), presumably are of lower quality. There are libraries of HRTFs available online from physical audio measurements, so perhaps a tedious possibility is trying a variety of those out in, say, Virtuoso, to see what anonymous HRTF might be a good match to yours. That is, assuming that Apple would allow such an HRTF to be imported.

In the early kickstarter days, the Realizer A16 “exchange service” was advertised as going to provide a way to “personalize” a PRIR, meaning, take someone else’s PRIR from the exchange and modify it with info gathered from your own measured PRIRs. This would be somewhat analogous to substituting your HRTF for the other person’s HRTF. Sadly, neither the Realizer Exchange nor this personalization feature was ever brought into production. In principle, comparing a measured Realizer PRIR with in-ear mics to one measured in the same room with the same mics on a stand might allow extraction of an HRTF-like personalization, but all of the Realizer data files, both HPEQs and PRIRs, are encrypted and no documentation or software is available to understand them.

There was popular binaural software called OOYH (Out of Your Head) about 9 or 10 years ago, and on Head-Fi (I think) I read about customized personalization that could be done for a fee that involved an in-person measurement. Both OOYH and that measurement, if those threads are to be believed, relied on the Realizer A16’s predecessor, the A8, and various data products (PRIRs) from the A8.

QuickTime or another media player definitely needs to support lossless Atmos in mp4 (or other format) files. I was sure I was able to play lossless Atmos via VLC from an MKV BluRay rip back when I was using Virtuoso, but I must have dreamt it because I haven’t been able to reproduce the process.

Given the serious amount of data processing power in an A16 (a couple of SHARC DSPs, at least one large FPGA, another TI DSP on the Atmos/Auro-3D/DTS:x decoder board), it may be quite a while before an iPhone will be competitive for doing analogous audio processing.

 

[Franck]

Does the documentation talk about the personalization for AirPods that you use an iPhone measurement with the 3D face recognition camera to produce? I know the mesh2hrtf folks support acquisition using an iPhone (IIRC a slightly older model than current is better for some reason), but the process is much more involved than the 30 seconds required with the Apple procedure. I’m also curious whether the Apple HRTF or pseudo-HRTF can be exported, say in a SOFA-format file.

see

• https://developer.apple.com/documentation/realitykit/scene-content-audio
• https://developer.apple.com/search/?q=HRTF&type=Documentation