This morning I've been testing Apple Music's new lossless and Hi-Res offerings on both my iPhone 12 Pro running iOS 14.6 and my Mac Mini (M1) running macOS 11.4. In my tests, I'm only concerned with playing the music bit perfectly, in other words without making any changes to the audio. If Apple Music says it's streaming lossless audio, then I want to stream that audio losslessly, rather than accidentally converting it to lossy AAC or MP3 etc... Whether or not people can hear the difference is a topic for another discussion. I'm just making sure I can play the music in its original form and that Apple is sending true lossless and Hi-Res to my audio devices.
Let's Dig in
What is bit perfect and why should I care? In the simplest terms, bit perfect means that the audio hasn't been changed. The music sent, in this case from Apple Music, into the playback device hasn't been altered. The source is what has been delivered to Apple by the record labels. Apple is just the delivery company.
If you care about high quality, getting the lossless streaming you're paying for from Apple Music, Qobuz, Tidal, Amazon Music, etc... then you should care about bit perfect because without it you have no idea what's happening to your audio. If this isn't a concern for you, no worries.
Testing Methodology
Device 1
My Apple iPhone 12 Pro running iOS 14.6 and the Apple Music app. I connected the newest version of the Apple Camera Connection Kit to the iPhone, so I could attach a USB Audi interface, and feed power to the phone and interface.
Device 2
Apple Mac Mini (M1) running macOS 11.4, and Apple Pro Display XDR, and USB audio interface connected to the ports on the back of the display.
I use the following testing methodology to test Apple Music.
The USB audio interface is a Berkeley Audio Design Alpha USB that accepts USB input and outputs audio over AES/EBU or S/PDIF (BNC).
I use a Berkeley Audio Design Alpha DAC Reference Series 3 that identifies and decodes HDCD on all sample rates from 44.1 up through 192 kHz. When an unaltered HDCD music track is played, the HDCD indicator on the DAC is illuminated. The HDCD flag is on the 16th bit for lossless CD files and the 24th bit for high resolution files. Any alteration, DSP, volume leveling, etc... changes this least significant bit and won't enable the HDCD indicator to illuminate on my DAC. Apple Music's lossless audio that I tested was 16 bit / 44.1 kHa and the Hi-Res audio was both 24 bit / 176.4 kHz and 24 bit / 192 kHz. That's the hardware piece.
With respect to source files, here's what I do.
I have a list of roughly ten known HDCD albums (although I could use more if needed). Many of these albums were only released as HDCD encoded CDs/files. There is no alternate lossless version. For example, Reference Recordings only releases CDs that are HDCD encoded. Pearl Jam's Live On Two Legs was only released as an HDCD master for its lossless CD version.
I set a baseline by playing my own local copy of the albums and make sure the HDCD indicator illuminates. I played some Reference Recordings albums through Apple Music on macOS and made sure the app could handle bit perfect playback. All was good there. On iOS, I used used other apps such as Qobuz, to play the identical music through the identical hardware. All was good through the Qobuz app. Again, there are no alternative versions of these lossless albums. It's the same music on all the services that offer lossless streaming.
Absolutely there are possible holes in my methodology, but I believe I've minimized them as much as possible. If anyone can identify a hole, please let me know and I will retest.
Test Results
On macOS, I found no way to play bit perfect lossless or Hi-Res audio from Apple Music. In addition to a couple other nonsensical issues that I'll get into later, Apple is doing something to the music it streams.
Test 1, streaming Pearl Jam's Live On Two Legs release I was able to illuminate the HDCD indicator for the first couple seconds of playback. After this, the light went out for good, even if I skipped to the next track. When I clicked the play button to start the entire album over again, the HDCD indicator illuminated again for a few seconds. If I had to guess, I'd say this is because of watermarking mandated by the major record labels. Apple has a perfect copy of the album on its servers, the perfect copy starts, but then something changes in the stream that causes the music to not be bit perfect. I'm open to all input on what this could possibly be, but watermarking is my best educated guess for now.
Test 2, streaming the Reference Recording's album Exactly Like This from Doug MacLeod, displays different behavior and bolsters my aforementioned watermarking theory. This album, from a very small independent record label that I don't believe watermarks it's music, alters between bit perfect and not bit perfect. Upon playback, the HDCD indicator is on sometimes then off for a period of time, then back on etc... I really don't have a good guess for why this happens. I originally thought maybe an adaptive bit rate issue caused it, but even after downloading the tracks to my device offline and playing them, the problem remained.
Test 3, streaming the Reference Recording's album Break The Chain from Doug MacLeod produced the identical behavior. The only difference here was that the album was Apple's Hi-Res offering at 24 bit 176.4 kHz. Again, no solid bit perfect playback. Something is happening to the music.
A note about Apple's Hi-Res offerings that makes this a real mess. On Macs running macOS / OS X, the Apple Music app looks at the sample rate in Audio Midi upon the app's launch. Whatever same rate is set there, is the sample rate that Apple Music will use for playback as long as the app is open. OK, fine you say, Apple Music lossless is probably 16 bit / 44.1 kHz and that can be set in Audio Midi. Sure, now for the mess. Apple Music Hi-Res is be definition not 16 bit / 44.1 kHz. It go up through 24 bit / 192 kHz. OK, you can run through the whole dance closing Apple Music, manually setting the sampan rate in Audio Midi, then reopening Apple Music and off you go. Oh no you can't. Apple Music doesn't tell you what the sample rate of its Hi-Res music albums. Thus, you have no idea at what sample rate to set Audio Midi.
UPDATE: To find the sample rate of the album and play it correctly you have to play a track, click the info button to reveal the sample rate, change Audio MIDI to correct sample rate, restart Apple Music, play the track again.
How did I find the same rate? Fortunately, the Apple Music app on iOS has auto sample rate switching, which enabled me to get the rate, then sixth back to my Mac to run the tests. This was good because I could see the bit perfect audio stream for the first few seconds once I had the correct sample rate set.
Note: the Qobuz app plays this music bit perfect on my Mac.
On iOS, as I just mentioned, we have the high benefit of automatic sample rate switching when playing music in Apple Music. The results for Test 1, 2, and 3 were identical on iOS as they were on macOS. Bit perfect for the first few seconds of major label albums. Bit perfect on and off for Reference recordings' albums. Apple Music on iOS switched between outputting 44.1 to outputting 176.4 without an issue. If only the audio would remain bit perfect during playback, it would be a great solution.
I will note that the Qobuz iOS app played everything bit perfect, but there needs to be an asterisk. For some reason Qobuz resamples the 176.4 Doug MacLeod album Break The Chain at 192 kHz on iOS rather than 176.4. I checked Neil Young's greatest hits to make sure I cold stream 192 material bit perfectly from Qobuz and succeeded. iOS and iPhones are fully capable of bit perfect audio at 176.4 kHz, so I'm not sure why Qobuz is resampling the RR releases.
What About mQa?
There is interesting news on this front. Some labels have snuck mQa material into Apple Music just like they have on other services. Users of Apple Music can search for mQa and they'll see some albums such as the Radka Toneff Fairytales album. The albums playback as mQa on a DAC in my system that is a full mQa decoder.
I checked a number of other albums that have appeared on Tidal as mQa only and didn't find mQa for these releases on Apple Music.
As readers of Audiophile Style know, I'm no fan of mQa and am very pleased it hasn't made its way into more releases or officially into Apple Music. Those who may be reading this as fans of Apple Music, rather than typical audiophile offerings, and aren't familiar with mQa, can get the gist of it and the company from the following videos.
Part 1 - https://youtu.be/pRjsu9-Vznc
Part 2 - https://youtu.be/NHkqWZ9jzA0
Wrap Up
As it stands now, Apple Music's lossless and Hi-Res offerings are a bit of a soup sandwich. You can't really stream the audio without some type of DSP going on that makes the music different from the lossless version on CD and on other lossless services. My guess is digital watermarking. In addition, it's not possible to get a consistent lossless or Hi-Res stream for other music that I tested, such as that from Reference Recordings. When I ran into similar issues with Amazon Music HD, using its apps just like I used the Apple Music apps, I was happy to find the Amazon Music HD streams lossless and Hi-Res through third party devices from Bluesound. Given that Apple doesn't integrate with Bluesound, I can't test this. Apple does integrate with Sonos, but as I found previously (link), the new Sonos Port can't stream bit perfect either, so a test on that platform would be useless.
I will happily update this article if there are holes in my tests or something else changes. As it stands now, I don't know of any holes and I stand by these conclusions.
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