Comment: Apple Music Lossless Audio – what we do and don’t know
A day after the Apple Music Lossless Audio announcement, there’s still a great deal of confusion. A few things have become clear in the meantime, but other elements remain murky.
Apple spent most of its press release talking about Spatial Audio, and very little talking about Lossless Audio. That wasn’t a surprise: Anyone with the right kit will be able to hear the benefit of the former, while rather few will be able to hear the lossless difference…
Since then, some questions have been answered.
Clear: No Bluetooth support
As we noted yesterday, it was mathematically obvious that you wouldn’t be able to listen to Hi-Res Lossless on any Bluetooth headphones. Streaming 24-bit audio at 192kHz requires 9.2Mbps, and Bluetooth 5.0 maxes out at 2Mbps.
Even that 2Mbps maximum bandwidth is theoretical. As soon as you get any distance between music source and headphones, the bitrate drops – which is why we said listening to lossless audio via Bluetooth was a nonstarter.
In response to an email from 9to5Mac, Apple confirmed this. The company said simply, “Lossless doesn’t work over Bluetooth.” That unqualified statement suggests Apple Music doesn’t even attempt to stream ALAC via Bluetooth, and that it automatically selects AAC.
However, that should have left AirPods Max compatible with lossless audio in wired use, but…
Clear: No AirPods Max support
Apple says no. You cannot listen to Apple Music Lossless Audio on AirPods Max even with a wired connection.
That’s a huge fail by Apple. Lots of people (for relative values of “lots”) have gone out and bought Apple’s most expensive headphones, but won’t be able to use them to listen to the best quality offered by Apple Music. Apple’s own hardware doesn’t fully support Apple’s own streaming music service.
Clear: No HomePod support
Bluetooth bandwidth can’t cope with lossless audio, but a Wi-Fi connection can. That immediately raised the possibility of HomePod supporting lossless streaming… but no. Apple says that neither the original nor HomePod mini speakers support Apple Music Lossless Audio.
Clear: Hi-Res Lossless needs an external DAC
Apple Music is of course streamed digitally. To be able to listen to it, it needs to be converted to analogue form.
Apple devices have built-in digital-to-analogue converters (DACs), but – unsurprisingly for devices that aren’t sold as audio kit – they are only mid-range ones. They max out at 24-bit at 48kHz. That’s good enough for the middle quality of Apple Music Lossless Audio, but not for the Hi-Res version.
If you want to listen to Hi-res Lossless (aka 24-bit at 192kHz), you’ll need to use an external DAC that supports this. This takes the digital signal from your Apple device, and does its own analogue conversion. You then plug wired headphones into the DAC.
Let’s then move onto the things that remain unclear…
Unclear: Why no wired AirPods Max support?
AirPods Max can work as wired headphones as well as wireless ones, so why don’t they support Lossless when used with a cable?
Apple tells the Verge that when you play a 24-bit/48kHz Apple Music lossless track from an iPhone into the AirPods Max using both the cable and Lightning dongle, the audio is converted to analog and then re-digitized to 24-bit / 48 kHz. That re-digitization step is the reason that Apple can’t say you’re hearing pure lossless audio; it’s not an identical match to the source.
Um, OK. In that scenario, the output format would be… who knows? It’s likely that the double-DAC process would introduce artifacts, and I don’t think there would be any way of knowing what to call the result. So sure, it would be safest for Apple to say that you don’t get Lossless Audio.
But why can’t AirPods Max use their Lightning cable to take a digital feed from the iPhone, then use the DAC built into the headphones to convert to 24-bit/48kHz lossless? Ok, it wouldn’t be Hi-res Lossless, but it would be unarguably mid-range lossless. Surely the DAC in Apple’s most expensive audio product has to be at least as good as the DAC in the iPhone?
The only explanation I can think of would be that AirPods Max don’t support ALAC, the lossless format used by Apple Music. That would make sense at a technical level in that it would explain the known facts, but it makes no sense at all on a marketing level. Why on earth would Apple launch a pair of premium headphones that aren’t going to fully work with its own music service?
Unclear: Why no HomePod support?
There’s enough bandwidth on AirPlay 2, so why no support?
HomePod mini doesn’t have anything like the level of quality needed to hear the difference, so the reason there is obvious: The speakers just aren’t good enough.
The same could be true of the original HomePod. While the audio quality is extremely impressive, it may well fall some way short of the standard needed to hear the lossless difference. Even so, Apple could have supported it and let people make up their own minds. I suspect the real answer here is that Apple didn’t want to create a mess by saying, “Yeah, so you get Lossless on our discontinued HomePod, but not on the model we still sell.”
Unclear: What happens when you use Apple’s Lightning adapter?
If you use an Apple device with a headphone socket, the position is clear: You can listen to Lossless Audio at 24-bit/48kHz, which is where Apple’s own DAC maxes out, but not Hi-Res Lossless.
The position is also clear(ish) if you use third-party Lighting headphones: It’s all down to the quality of the DAC built into the headphones. The iPhone passes a digital signal to the headphones, and it’s their DAC that handles the conversion. If it’s a high-quality one, it will be able to handle 24-bit/192kHz, and you’ll be able to listen to Hi-Res Lossless. If it’s a lesser one, you won’t. So, check the specs of your Lightning headphones.
But what if you have high-quality analogue headphones, which support ALAC and are good enough to hear the difference? Can those also play 24-bit/48kHz lossless without an external DAC?
To connect them to a current iPhone, you’d have to use Apple’s Lightning to 3.5mm headphone jack adapter. But… you’d now be using the DAC built into the adapter instead of the one built into the phone. (The iPhone sends a digital signal through the Lightning socket to the adapter, whose DAC converts it into the analogue signal needed by your headphones.) What quality is that DAC?
I’m guessing it’s the same one built into the iPhone, but I haven’t heard any official world from Apple.
Wrap-up on Apple Music Lossless Audio knowledge
So, this is what I think we do and don’t know…
You can’t listen to Apple Music Lossless Audio via Bluetooth; on AirPods Max (even with a wired connection); on HomePod (original or mini).
Using analogue headphones on an Apple device with a headphone socket, you can listen to the mid-quality, which is 24-bit/48kHz.
On Lightning headphones, the quality you get depends on the capability of the DAC in the headphones – check the specifications or ask the manufacturer.
When using Apple’s Lighting adapter, unknown. I’m guessing 24-bit/48kHz, but that is just a guess.
Can anyone shed any more light? If so, do please share in the comments!
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via 9to5Mac https://9to5mac.com
May 18, 2021 at 07:52AM