Carlo_M
Senior HTF Member
- Joined
- Oct 31, 1997
- Messages
- 13,392
This is intended to discuss only the flawed ability to play (and in some cases the inability to play) Spatial Audio (SA) and high-resolution lossless (HRL) music in Apple's ecosystem using their own devices. This will not discuss the merits of whether an album should be remixed in Spatial Audio, that would be an entire other thread with passionate responses for and against it. This is simply to discuss the concept of: if you are going to offer SR/HRL, and brag about it, then your devices should easily and flawlessly allow for the user to enjoy the full benefit of the SA/HRL files. This means flawless playback for the SA files, free from audio dropouts and glitches, and additionally for HRL, full transmission of the file to your receiver for decoding (e.g. 24-bit 96kHz files should be streamed at that rate to your [compatible] AVR for decoding, rather than being downconverted by an Apple device to a lower bit rate like 16-bit/48kHz and then sent to your AVR.
Problem 1: Inconsistency of albums containing a mish-mosh of Spatial Audio and normal stereo tracks.
It wasn't that long ago that Apple touted both the arrival of high resolution lossless (defined as anything greater than 16/44.1) and Spatial Audio (delivered via Dolby Atmos). If you have an Apple Music subscription, you'll see that while there are some 24/48 HRL songs/albums, there are also a good amount of 24/96 and even some 24/192 files. There's also a decent amount of SA albums and tracks. That latter part "tracks" is somewhat vexing to offer, though. Because while there are entire albums in Spatial Audio, there are others where there are only tracks in Spatial Audio (presumably to use in Apple's Playlists (e.g. 1980s Hard Rock/Metal) where they took a band's popular songs and gave it the SA treatment, but left the rest of the album in Stereo. As of this writing, an easy example to point to is Guns & Roses Appetite for Destruction. You won't have to think hard to guess which tracks are in SA: Welcome to the Jungle, and Sweet Child O' Mine. Surprisingly, Paradise City isn't. So what this results in for the listener who prefers to listen to albums is a jarring jump between Spatial Audio (in my case 5.1.2 Atmos) and "high resolution stereo" for all the other tracks (I used quotation marks because the other tracks are 24-bit 44.1 kHz which is just barely qualifying specs for HRL). Not only is the switch from a full 360° sound to stereo and then back again.
But as jarring as switching between stereo and Atmos is, it's nothing compared to the glitch/audio dropout that it generates which brings us to the next two issues...
Problem 2: Leading Audio sound dropouts for SA (Atmos) tracks on Apple TV 4K 2021 and 2022 versions
As long as I've been into Home Theater and owned surround sound AVRs, they have all, without exception, needed a half second or so to detect the signal and then assign the proper decoding codec to it. And I am not talking about the cheap $150 mass market receivers, I'm talking $1500+ receivers over the year from NAD, to Sony ES, to Pioneer Elites, to Denon X series. I've owned them all and they all need that split second. Makes sense. The chip has to decide between dozens of combinations of codecs and bit rates (is it stereo PCM? is it Dolby Digital? DTS? Atmos?) and it doesn't do it instantaneously. Now for movies, it's never mattered much because most if not all movies don't just suddenly launch into the soundtrack. Usually there's some studio logo and leading silence so that the receiver has more than enough time to detect the signal before the movie actually starts playing. For some studio logos like the new Sony/Columbia logo that sometimes starts its intro music as soon as the movie starts, missing the first 0.5 seconds of that won't ruin anyone's movie experience.
But missing the first half second (or more) of a song? That's a problem. And sure, if the entire album is SA, you only miss the first half second of the first song and no more. But in the case of mix-mode albums like Appetite for Destruction? You're gonna miss the first bit of Welcome to the Jungle (which has an iconic leading guitar riff) as well as Sweet Child O' Mine. And a bit of the songs following when the receiver has to re-sense that it's going back to stereo. That's annoying.
It happens on both 2021 and 2022 Apple TV 4K (64GB for 2021, 128GB for 2022, so top of the line model for both).
The first solution is: if you're going to SA master a few tracks...do the whole album. Or don't do it at all. That will solve the in-album dropouts.
The second solution, to address leading track dropouts (e.g. when you first begin playing an SA track or album) and I am not a programmer so I can only speculate that this should be possible...when you press play on a SA track or album, the Apple TV should first sense what format the album/track is in (e.g. Atmos) and append a silent 1 second signal of that to your AVR to get it to enter Atmos decoding mode and then start the actual track. That full second should allow even the slower sensing AVRs to lock into the signal.
But there's still a second problem with audio dropouts on the ATV4K...
Problem 3: Lack of Gapless Playback for SA/Atmos tracks
This oversight is ironic given how some of the iconic full-length albums that get the SA/Atmos treatment actually require gapless playback. For those who don't know, gapless playback is needed for instances where one song/track seamlessly blends into another track with no silence in between, so the instruments never stop playing. A classic example of this is The Beatles Abbey Road album (side 2 "medley") and many of Pink Floyd's tracks on Wish You Were Here, The Wall and Dark Side of the Moon. Also many classical recordings have continuous music that go from one track to the next. Try listening to Mean Mr. Mustard > Polythene Pam > She Came In Through the Bathroom Window on Abbey Road in Atmos and tell me those pauses between songs don't annoy the heck out of you and ruin the experience.
Problem 4: Apple TV 4K 2022 still doesn't support HRL
It was already shocking when the 2021 ATV4K didn't support HRL. But I cut them some slack. The SA/HRL announcement was still relatively new, maybe the 2021 ATV4K with its aging A12 Bionic chip just wasn't capable of it. I cut them that slack. But the 2022 ATV4K has an A15 Bionic chip that debuted in September 2021, is on the iPhone 13 Pro/Max line, and should have more than enough CPU power to decode HRL.
Apple: This is just offensive now. If ATV4K is supposed to be your flagship All-In-One shop for all things movies and music, and I subscribe to your Apple One (which includes Music) subscription, why am I not able to play back all of the high-quality files I'm paying for in your top-of-the-line 2022 ATV4K?
Problem 5: Workaround needed to get anything higher than 24/48 to your AVR for HRL out of your expensive Macs (so ATV4Ks aren't the only problem)
So HRL on ATV4K is a no-go as of this writing. But what about if you have a multi-thousand dollar Macbook Pro with HDMI? If you connect your Mac via HDMI to your AVR...you get something way less than the 24/96 or 24/192 signal (I want to say it was 24/48). Or if you have a multi-thousand current Macbook Pro with USB-C and headphone out, well you know most AVRs don't have a USB-C signal (I can only surmise a USB-C to HDMI cable will yield the same result as HDMI to HDMI 24/48 cap, but if anyone wants to try it out and report I'll be happy to include it). The other option is you can use your headphone out which again caps it at way less than 24/96 or 24/192.
Turns out, if you want to get everything you're paying for, you have to buy an external DAC and run USB-C to it. I bought a Topping DX5 DAC ($450 so not too bad) and connecting that to the Mac suddenly opens up a world of possibilities where the Mac allows you to choose the bit rate and depth you want to send to the DAC. However if you don't want the DAC to do any up- or down-sampling, you have to change the output to match the track/album. So if you're playing a 24/192 album, set your Mac to output that. But if you are playing a 24/96, you have to change the output to match that to get the native file quality. If you don't, the Mac will up- or down-scale the file to match the output specs. Now I don't think anyone can hear a difference between a 24/96 file being upscaled to 24/192 vs. native playback (or vice versa) but it's the principal of the matter. A file at a certain bit rate and depth should be played back and decoded at the proper specs without up- or down-conversion, or manual user intervention to change the output setting to your external DAC (which you shouldn't have to buy in the first place, IMO).
All of this is just an annoying for a company whose slogan used to be "it just works". Or perhaps that's gone away with Steve Jobs passing...
Problem 1: Inconsistency of albums containing a mish-mosh of Spatial Audio and normal stereo tracks.
It wasn't that long ago that Apple touted both the arrival of high resolution lossless (defined as anything greater than 16/44.1) and Spatial Audio (delivered via Dolby Atmos). If you have an Apple Music subscription, you'll see that while there are some 24/48 HRL songs/albums, there are also a good amount of 24/96 and even some 24/192 files. There's also a decent amount of SA albums and tracks. That latter part "tracks" is somewhat vexing to offer, though. Because while there are entire albums in Spatial Audio, there are others where there are only tracks in Spatial Audio (presumably to use in Apple's Playlists (e.g. 1980s Hard Rock/Metal) where they took a band's popular songs and gave it the SA treatment, but left the rest of the album in Stereo. As of this writing, an easy example to point to is Guns & Roses Appetite for Destruction. You won't have to think hard to guess which tracks are in SA: Welcome to the Jungle, and Sweet Child O' Mine. Surprisingly, Paradise City isn't. So what this results in for the listener who prefers to listen to albums is a jarring jump between Spatial Audio (in my case 5.1.2 Atmos) and "high resolution stereo" for all the other tracks (I used quotation marks because the other tracks are 24-bit 44.1 kHz which is just barely qualifying specs for HRL). Not only is the switch from a full 360° sound to stereo and then back again.
But as jarring as switching between stereo and Atmos is, it's nothing compared to the glitch/audio dropout that it generates which brings us to the next two issues...
Problem 2: Leading Audio sound dropouts for SA (Atmos) tracks on Apple TV 4K 2021 and 2022 versions
As long as I've been into Home Theater and owned surround sound AVRs, they have all, without exception, needed a half second or so to detect the signal and then assign the proper decoding codec to it. And I am not talking about the cheap $150 mass market receivers, I'm talking $1500+ receivers over the year from NAD, to Sony ES, to Pioneer Elites, to Denon X series. I've owned them all and they all need that split second. Makes sense. The chip has to decide between dozens of combinations of codecs and bit rates (is it stereo PCM? is it Dolby Digital? DTS? Atmos?) and it doesn't do it instantaneously. Now for movies, it's never mattered much because most if not all movies don't just suddenly launch into the soundtrack. Usually there's some studio logo and leading silence so that the receiver has more than enough time to detect the signal before the movie actually starts playing. For some studio logos like the new Sony/Columbia logo that sometimes starts its intro music as soon as the movie starts, missing the first 0.5 seconds of that won't ruin anyone's movie experience.
But missing the first half second (or more) of a song? That's a problem. And sure, if the entire album is SA, you only miss the first half second of the first song and no more. But in the case of mix-mode albums like Appetite for Destruction? You're gonna miss the first bit of Welcome to the Jungle (which has an iconic leading guitar riff) as well as Sweet Child O' Mine. And a bit of the songs following when the receiver has to re-sense that it's going back to stereo. That's annoying.
It happens on both 2021 and 2022 Apple TV 4K (64GB for 2021, 128GB for 2022, so top of the line model for both).
The first solution is: if you're going to SA master a few tracks...do the whole album. Or don't do it at all. That will solve the in-album dropouts.
The second solution, to address leading track dropouts (e.g. when you first begin playing an SA track or album) and I am not a programmer so I can only speculate that this should be possible...when you press play on a SA track or album, the Apple TV should first sense what format the album/track is in (e.g. Atmos) and append a silent 1 second signal of that to your AVR to get it to enter Atmos decoding mode and then start the actual track. That full second should allow even the slower sensing AVRs to lock into the signal.
But there's still a second problem with audio dropouts on the ATV4K...
Problem 3: Lack of Gapless Playback for SA/Atmos tracks
This oversight is ironic given how some of the iconic full-length albums that get the SA/Atmos treatment actually require gapless playback. For those who don't know, gapless playback is needed for instances where one song/track seamlessly blends into another track with no silence in between, so the instruments never stop playing. A classic example of this is The Beatles Abbey Road album (side 2 "medley") and many of Pink Floyd's tracks on Wish You Were Here, The Wall and Dark Side of the Moon. Also many classical recordings have continuous music that go from one track to the next. Try listening to Mean Mr. Mustard > Polythene Pam > She Came In Through the Bathroom Window on Abbey Road in Atmos and tell me those pauses between songs don't annoy the heck out of you and ruin the experience.
Problem 4: Apple TV 4K 2022 still doesn't support HRL
It was already shocking when the 2021 ATV4K didn't support HRL. But I cut them some slack. The SA/HRL announcement was still relatively new, maybe the 2021 ATV4K with its aging A12 Bionic chip just wasn't capable of it. I cut them that slack. But the 2022 ATV4K has an A15 Bionic chip that debuted in September 2021, is on the iPhone 13 Pro/Max line, and should have more than enough CPU power to decode HRL.
Apple: This is just offensive now. If ATV4K is supposed to be your flagship All-In-One shop for all things movies and music, and I subscribe to your Apple One (which includes Music) subscription, why am I not able to play back all of the high-quality files I'm paying for in your top-of-the-line 2022 ATV4K?
Problem 5: Workaround needed to get anything higher than 24/48 to your AVR for HRL out of your expensive Macs (so ATV4Ks aren't the only problem)
So HRL on ATV4K is a no-go as of this writing. But what about if you have a multi-thousand dollar Macbook Pro with HDMI? If you connect your Mac via HDMI to your AVR...you get something way less than the 24/96 or 24/192 signal (I want to say it was 24/48). Or if you have a multi-thousand current Macbook Pro with USB-C and headphone out, well you know most AVRs don't have a USB-C signal (I can only surmise a USB-C to HDMI cable will yield the same result as HDMI to HDMI 24/48 cap, but if anyone wants to try it out and report I'll be happy to include it). The other option is you can use your headphone out which again caps it at way less than 24/96 or 24/192.
Turns out, if you want to get everything you're paying for, you have to buy an external DAC and run USB-C to it. I bought a Topping DX5 DAC ($450 so not too bad) and connecting that to the Mac suddenly opens up a world of possibilities where the Mac allows you to choose the bit rate and depth you want to send to the DAC. However if you don't want the DAC to do any up- or down-sampling, you have to change the output to match the track/album. So if you're playing a 24/192 album, set your Mac to output that. But if you are playing a 24/96, you have to change the output to match that to get the native file quality. If you don't, the Mac will up- or down-scale the file to match the output specs. Now I don't think anyone can hear a difference between a 24/96 file being upscaled to 24/192 vs. native playback (or vice versa) but it's the principal of the matter. A file at a certain bit rate and depth should be played back and decoded at the proper specs without up- or down-conversion, or manual user intervention to change the output setting to your external DAC (which you shouldn't have to buy in the first place, IMO).
All of this is just an annoying for a company whose slogan used to be "it just works". Or perhaps that's gone away with Steve Jobs passing...
