Apple Music Lossless + Apple TV 4K + Airplay + Airport Express (version 1)

[carlo_b]

According to my information, via Airplay version 1 any audio format is converted to ALAC 16 / 44.1 by the sending device before being sent to the receiving device.
Also based on my information, the Apple TV 4K has a fixed audio output at 16/48.

Apple Music sends in ALAC format up to 24/48 if lossless audio quality is selected on Apple TV 4K.
To listen to Apple Music on my Apple TV 4K I don't use the HDMI audio output but I use Airplay version 1 + Airport Express version 1.

I also use Apple Music + Phone X + Airplay 1 + Airport Express 1 (bitperfect at 16 / 44.1 according to the tests done here - https://audiophilestyle.com/ca/bits...ss-mess-part-2-airplay-r1026/page/5/#comments) but I prefer to use Apple TV to not drain the battery of the iPhone.
[[I use iPhone to control Apple TV remotely with the Music app (it is a pity that through the iPhone Music app it is not possible to select Airplay 1 devices available for Apple TV .. it is not even possible to select an Airplay 1 device as default audio output but only HomePod = Airplay 2 .. every time you need to turn on the TV and use the Apple TV control center to select an Airplay device 1)]]

My question is:

What happens when I receive a lossless 16.44.1 format from Apple Music on my Apple TV 4K which I then send via Airplay 1 to my Airport Express 1?
Airport Express 1 receives from Apple TV 4K lossless bitperfect ALAC 16 / 44.1?
Apple Music on tvOS, is it bitperfect like iOS at 16 / 44.1 using Airplay 1?

I forgot to say one thing. Airport Express 1 is connected to my Naim UnitiQute 1 via digital input and the Naim app confirms to receive 44.1.

 

[Snoopy]

I quess the apple TV upsamples everything to 48khz and the AirPlay express downsamples it to 44.1khz again

 

[carlo_b]

Unfortunately I think you have guessed.

I made comparisons between the original track in my possession (CD 16 / 44.1) and the same track in RAW format sent to shairport-sync + stdout from Apple TV4K. Through Audition, by reversing the polarity of one of the two tracks, I verified that the two tracks do not cancel each other out completely but you can still hear a low sound.

Doing the same thing with iPhone 12, however, the two tracks are completely canceled and no audio is heard.

Apple's behavior is very "bizarre":

- Apple TV4K receives ALAC lossless 16 / 44.1 from Apple Music server;

- Apple TV4K converts lossless ALAC to 16/48 before sending it to any output (HDMI or AirPlay) as it is meant to play video;

- AirPlay converts lossless ALAC to 16 / 44.1 before sending it to AirPort Express 1 as AirPlay 1 devices can only receive in this format.

The conversion done by the Apple ecosystem results in non-bit perfect streaming.

Absurd!

 

[Snoopy]

It's not only apple.. TVs upsample everything to 48khz (optical out), android uses 48khz upsampling.a

 

[NiagaraPete]

Why don't you update shairport-sync to airplay 2? It supports higher bit rates and frequencies.

 

[ElNino]

Why don't you update shairport-sync to airplay 2? It supports higher bit rates and frequencies.

Unfortunately, this doesn't do it. The support for other bit rates and frequencies in shairport-sync is only for output devices. The transport, even for Airplay 2, is limited to 44.1/16 or 44.1/AAC. See here: https://github.com/mikebrady/shairport-sync/blob/development/AIRPLAY2.md

The Airplay 2 protocol itself supports transport at either 44.1 or 48kHz (see here: https://emanuelecozzi.net/docs/airplay2/audio/) but it's unknown whether the NDA'd receiver specs contemplate any higher sample rate. There are iOS APIs to send higher bit sample rate data, but they currently get downsampled on the sending device at a lower level of the OS before being sent out.

 

[Beershaun]

Yep. Welcome to the disappointment that is mobile operating systems. The struggle is real for us audiophiles. both Apple and Android have done a lot of work to make it very hard to get bit perfect audio out of their devices.

 

[mdsimon2]

Or stop stressing over something being "bitperfect" and just listen and be happy. The apple resampler is quite good and easily retains 16 bit fidelity.

Michael

 

[ElNino]

Yep. Welcome to the disappointment that is mobile operating systems. The struggle is real for us audiophiles. both Apple and Android have done a lot of work to make it very hard to get bit perfect audio out of their devices.

So true!

On the positive side, at least a direct cable connection from an iPad to a USB DAC finally does automatic sample rate switching, even at higher sample rates.

 

[carlo_b]

my Apple Music Lossless summary ...

 

[ElNino]

View attachment 157520 my Apple Music Lossless summary ...

That's a great chart, but I think the first line of that chart should be "system dependant", rather than "no". It wasn't working right for the Audiophilestyle guy in his rig, but at least two people have confirmed that it is bit-perfect with a direct USB connection to an RME device. My guess is that it's something related to the XMOS implementation in the Audiophilestyle guy's system.

Apologies for the edit -- I just tried it on my own RME system, and using the RME bit-check function, I can only get a bit-perfect pass at 16-bit. i.e., 44.1/48/96/192kHz all report passing the bit-perfect test at 16-bits, but NOT at 24-bit or 32-bit. The 24-bit test passes for a bit and then flakes out and then reports passing at 16-bit only, just like the AudiophileStyle guy reported.

Still, you might want to update the chart to show that high sample rates can be bitperfect at all sample rates at 16-bit.

 

[sarumbear]

According to my information, via Airplay version 1 any audio format is converted to ALAC 16 / 44.1 by the sending device before being sent to the receiving device.
Also based on my information, the Apple TV 4K has a fixed audio output at 16/48.

Apple Music sends in ALAC format up to 24/48 if lossless audio quality is selected on Apple TV 4K.
To listen to Apple Music on my Apple TV 4K I don't use the HDMI audio output but I use Airplay version 1 + Airport Express version 1.

I also use Apple Music + Phone X + Airplay 1 + Airport Express 1 (bitperfect at 16 / 44.1 according to the tests done here - https://audiophilestyle.com/ca/bits...ss-mess-part-2-airplay-r1026/page/5/#comments) but I prefer to use Apple TV to not drain the battery of the iPhone.
[[I use iPhone to control Apple TV remotely with the Music app (it is a pity that through the iPhone Music app it is not possible to select Airplay 1 devices available for Apple TV .. it is not even possible to select an Airplay 1 device as default audio output but only HomePod = Airplay 2 .. every time you need to turn on the TV and use the Apple TV control center to select an Airplay device 1)]]

My question is:

What happens when I receive a lossless 16.44.1 format from Apple Music on my Apple TV 4K which I then send via Airplay 1 to my Airport Express 1?
Airport Express 1 receives from Apple TV 4K lossless bitperfect ALAC 16 / 44.1?
Apple Music on tvOS, is it bitperfect like iOS at 16 / 44.1 using Airplay 1?

I forgot to say one thing. Airport Express 1 is connected to my Naim UnitiQute 1 via digital input and the Naim app confirms to receive 44.1.

The simple answer is nobody knows.

 

[MarkS]

my Apple Music Lossless summary ...

What does "Only if the systemwide Airplay device is set" mean?

On my MacBook Air laptop, I can choose to cast sound from Apple Music to an Airplay 1 receiver, but other system sounds are not cast, and go to the laptop speakers. Or, I can cast all sound using the "Sound" panel in System Preferences. Are you saying that only in the second case is the cast CD-quality sound bit-perfect? If so, what happens to it when I cast from Apple Music only?

 

[BitPerfect_]

my Apple Music Lossless summary ...

AppleMusic 16/44.1 > iOS > Yamaha WXC-50 in Player mode, volume @100% by default, AirPlay 1 > will deliver 48kHz, not bit perfect.

 

[jhaider]

Or stop stressing over something being "bitperfect" and just listen and be happy.

This, exactly. Last I checked, an MD5 hash isn’t a marker of audibility.

Has anyone actually showed this whatever-is-going-on (don’t know, don’t care) results in audible differences in musical program playback in controlled circumstances?

 

[MarkS]

No, but then about 99% of what gets discussed here at ASR about electronics performance isn't audible.

 

[jhaider]

No, but then about 99% of what gets discussed here at ASR about electronics performance isn't audible.

Sort of. There are edge cases where a higher SNR for example, can be audible. But unless proven to make an audible difference on musical program I will consider "bit perfect" or "hi-rez" discussions every bit as stupid and pointless as wire discussions.

 

[Zensō]

That's a great chart, but I think the first line of that chart should be "system dependant", rather than "no". It wasn't working right for the Audiophilestyle guy in his rig, but at least two people have confirmed that it is bit-perfect with a direct USB connection to an RME device. My guess is that it's something related to the XMOS implementation in the Audiophilestyle guy's system.

Apologies for the edit -- I just tried it on my own RME system, and using the RME bit-check function, I can only get a bit-perfect pass at 16-bit. i.e., 44.1/48/96/192kHz all report passing the bit-perfect test at 16-bits, but NOT at 24-bit or 32-bit. The 24-bit test passes for a bit and then flakes out and then reports passing at 16-bit only, just like the AudiophileStyle guy reported.

Still, you might want to update the chart to show that high sample rates can be bitperfect at all sample rates at 16-bit.

I wonder what’s going on here? I’ve run the RME test files multiple times and passed every test, 16- and 24-bit. This is on an iPad via CCK direct to the RME.

 

[mdsimon2]

This, exactly. Last I checked, an MD5 hash isn’t a marker of audibility.

Has anyone actually showed this whatever-is-going-on (don’t know, don’t care) results in audible differences in musical program playback in controlled circumstances?

Although not with music I've done some simple measurements of shairport-sync as well as true Airplay 1/2 on Apple TVs (frequency stepped FFTs, frequency response measurements) to convince myself that airplay still retains 16 bit fidelity (-96 dB THD+N). I've also done measurements of other resamplers which are not so great (Linux ALSA resampler) which definitely do not retain 16 bit fidelity.

Not all resamplers are created equal but the Apple one does it's job well.

Agree with you that in vast majority of cases worrying about if something is "bit perfect" is like worrying about cable sound quality.

Michael

 

[carlo_b]

What does "Only if the systemwide Airplay device is set" mean?

On my MacBook Air laptop, I can choose to cast sound from Apple Music to an Airplay 1 receiver, but other system sounds are not cast, and go to the laptop speakers. Or, I can cast all sound using the "Sound" panel in System Preferences. Are you saying that only in the second case is the cast CD-quality sound bit-perfect? If so, what happens to it when I cast from Apple Music only?

Apple Music Lossless Mess Part 2: AirPlay

Earlier this month I dug into Apple Music's Lossless and Hi-Res offerings, running several bit perfect rests on the audio output of my Macs and iOS devices. The results were less than stellar (link). This week I dug into Apple Music lossless over AirPlay. One would think that the results would be...

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