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High Res on AirPods Max when using the lightning cable
- Thread starter H-B0mb
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Apologies in advance for using your post to springboard into some thoughts I wanted share based on what I've puzzled out so far:
For any of these streaming services, there's going to be a DAC somewhere in that chain. We know for high res ( > 48khz) it'll require an external DAC capable of handling those higher sampling rates.
For the standard lossless ( up to 48khz), I'm not sure your statement holds true. Yes there is going to be a conversion at some point-- but that could happen at any point. For the AirPods Max, it's happening between the headphone's DSP and the drivers themselves-- they have their own DAC, right? No other way to get sound out of those analog drivers. So, if someone wants that control / freedom to use a different DAC & amp, they of course need some good old-fashioned analog headphones. But I don't think that has anything to do with the ability to get a lossless signal to headphones like the AirPods Max.
So, I own the Bang & Olufsen BeoPlay H95. These are very very similar to the AirPods Max in terms of how they are designed: they cannot be passively driven with an analog signal. Even if you use the 3.5mm input on the H95, they must be powered on and I'm pretty confident they are also doing DSP on that signal before passing it to the DAC and then the drivers*. (Accordingly I'm sure they have an ADC built in as well to handle that 3.5mm analog input prior to the DSP these are applying to the sound). You get B&O's tuning, you're not going to use an external amp / DAC with these, as you've illustrated. This doesn't mean they can't get a lossless source of audio, however.
I just plugged a USB-C cable into my H95 and the other end into a USB-C port on my MacBook Pro. It shows up as a USB audio output on my Mac. I am getting the audio from my Mac directly on my H95 via USB. There's no analog connection anywhere between my Mac and the H95, and bluetooth is turned off.
For kicks, I signed up for Amazon Music HD today, and the music I'm listening to is lossless-- Amazon's app tells me that although the track quality is 24-bit / 96kHz, the Device is only capable of and is currently playing at 24 bit / 48kHz.
Now, that 24-bit / 48kHz data is not hitting the DAC in these headphones directly-- that audio is being processed just as it would be on the AirPods Max and the DAC is getting something different than was sent by my Mac. Maybe this is why Apple says that the APM isn't capable of playing back lossless even over the 3.5 - lightning cable (aside from the ADC that's happening in that cable)-- they could just be being careful (or even technical) in their messaging. (Could explain the HomePods too, which are also doing a lot of processing to the signal they're getting).
Theoretically I should be getting better sound by listening to these lossless tracks via USB than I would be over bluetooth (with the lossy compression that gets introduced). I'm not to the point of wanting to spend much time A/B testing that
Mostly I was curious how things were working and why it wouldn't be possible to get lossless via a digital physical connection if I wanted to.In any case, for the APM, there are 2 basic possible reasons, in my mind, why we can't use a USB-C > lightning cable to send (lossless or not) audio digitally to the APM. Either A) there's a technical limitation with how they've set up that lightning input or some other necessary component is missing to enable USB audio-- which would be a sad oversight-- or B) It's technically capable of direct USB connection but they're not interested in enabling it via software / firmware.
Perhaps we'll learn eventually. Or they'll enable it. Or Apple will just release a new set of headphones that have this functionality included to the chagrin of the early APM adopters
(and maybe include USB-C in instead of lightning like many believe they should have.) *the evidence I have for this is that B&O has an app that you can use to adjust the ANC settings as well as some EQ options of your headphones. While listening to music via USB from my Mac, I'm able to use that app from my iPhone and change the EQ that I'm getting on the headphones-- I do hear the sound signature change as I manipulate the EQ.
No apologies needed. It's good to hold one accountable and make corrections, as needed.Apologies in advance for using your post to springboard into some thoughts I wanted share based on what I've puzzled out so far:
For any of these streaming services, there's going to be a DAC somewhere in that chain. We know for high res ( > 48khz) it'll require an external DAC capable of handling those higher sampling rates.
For the standard lossless ( up to 48khz), I'm not sure your statement holds true. Yes there is going to be a conversion at some point-- but that could happen at any point. For the AirPods Max, it's happening between the headphone's DSP and the drivers themselves-- they have their own DAC, right? No other way to get sound out of those analog drivers. So, if someone wants that control / freedom to use a different DAC & amp, they of course need some good old-fashioned analog headphones. But I don't think that has anything to do with the ability to get a lossless signal to headphones like the AirPods Max.
So, I own the Bang & Olufsen BeoPlay H95. These are very very similar to the AirPods Max in terms of how they are designed: they cannot be passively driven with an analog signal. Even if you use the 3.5mm input on the H95, they must be powered on and I'm pretty confident they are also doing DSP on that signal before passing it to the DAC and then the drivers*. (Accordingly I'm sure they have an ADC built in as well to handle that 3.5mm analog input prior to the DSP these are applying to the sound). You get B&O's tuning, you're not going to use an external amp / DAC with these, as you've illustrated. This doesn't mean they can't get a lossless source of audio, however.
I just plugged a USB-C cable into my H95 and the other end into a USB-C port on my MacBook Pro. It shows up as a USB audio output on my Mac. I am getting the audio from my Mac directly on my H95 via USB. There's no analog connection anywhere between my Mac and the H95, and bluetooth is turned off.
For kicks, I signed up for Amazon Music HD today, and the music I'm listening to is lossless-- Amazon's app tells me that although the track quality is 24-bit / 96kHz, the Device is only capable of and is currently playing at 24 bit / 48kHz.
Now, that 24-bit / 48kHz data is not hitting the DAC in these headphones directly-- that audio is being processed just as it would be on the AirPods Max and the DAC is getting something different than was sent by my Mac. Maybe this is why Apple says that the APM isn't capable of playing back lossless even over the 3.5 - lightning cable (aside from the ADC that's happening in that cable)-- they could just be being careful (or even technical) in their messaging. (Could explain the HomePods too, which are also doing a lot of processing to the signal they're getting).
Theoretically I should be getting better sound by listening to these lossless tracks via USB than I would be over bluetooth (with the lossy compression that gets introduced). I'm not to the point of wanting to spend much time A/B testing that
In any case, for the APM, there are 2 basic possible reasons, in my mind, why we can't use a USB-C > lightning cable to send (lossless or not) audio digitally to the APM. Either A) there's a technical limitation with how they've set up that lightning input or some other necessary component is missing to enable USB audio-- which would be a sad oversight-- or B) It's technically capable of direct USB connection but they're not interested in enabling it via software / firmware.
Perhaps we'll learn eventually. Or they'll enable it. Or Apple will just release a new set of headphones that have this functionality included to the chagrin of the early APM adopters
*the evidence I have for this is that B&O has an app that you can use to adjust the ANC settings as well as some EQ options of your headphones. While listening to music via USB from my Mac, I'm able to use that app from my iPhone and change the EQ that I'm getting on the headphones-- I do hear the sound signature change as I manipulate the EQ.
In terms of audio on a Mac, their Core Audio(1) does the conversion - whether upsampling or downsampling - based on what the end device is capable of handling.
For the APM, the (final) conversion will always happen in the headphone's DAC. Whether you're using a cable or Bluetooth. So if you're playing files higher than what it's capable of playing, then Core Audio will convert that before feeding it directly to the APM (wirelessly in digital form) or via the cable (wired in analog form).
I'm not sure what you're arguing on if you're for or against, but based on what is currently available you will never be able to get Apple's Lossless signal to the APM.
Even if they turn on a switch inside the APM to enable Lightning to Lightning digital feed, I'm guessing the internal DAC of the APM is not capable of anything other than AAC. I'd love for this to be not true.
And you will never be able to get an analog signal to the APM because they don't have an analog signal input. So again, no matter how much more conversion you do outside of the APM - it will always be converted in the cable and then converted again in the APM.
I had a B&O H4 2nd Gen and it was capable of playing analog audio without powering on. So I'm surprised a higher H95 model can't do this? In any case I sold that and purchased a Dali IO-6, and that is also capable of getting an analog signal without powering on. In both of those headphones, you can feed high quality audio signal and bypass the internal DAC with your own DAC + Amp.
Back to your H95. Have you checked in your Audio MIDI Setup app to see what's the maximum format the built-in DAC is capable of handling? It usually defaults to 48kHz. In my case, I have two DACs connected to my Mac and whenever I shut it off I have to go back in and re-set the format to higher than that, if needed.
(1) Per Apple's Core Audio Developer documentation:
"In OS X, Core Audio expects audio data to be in native-endian, 32-bit floating-point, linear PCM format. You can use Audio Converter Services to translate audio data between different linear PCM variants. You also use these converters to translate between linear PCM and compressed audio formats such as MP3 and Apple Lossless."
I don't know that I'm making a specific argument, I'm more just curious about how these devices are built and why they have the limitations they do. Thanks for bearing with me and instructing me-- I'm learning as I work through this. So, you were right in the sense that, even if you got a digital usb > lightning connection the Mac would see that the DAC of the APM is only capable of 256kbps and would downsample that lossless audio accordingly (via Core Audio).
I guess I wouldn't have guessed that the DAC in the APM would have that limitation. I do see others saying this is the case, however. I wonder if it has to do (aside from the limitations of bluetooth) with the sheer amount of calculations the H1's DSP is performing and how much data it can keep up with. Again this is just me wondering out loud because I don't know much about the math that goes into what's happening on the APM. If that were the case... it's possible we would later see an H2 chip or something that could handle a higher bitrate.
In another thread, someone said the HomePod had the same DAC limitation, but from what I can find from iFixit's teardown, the DAC in the HomePod (original) is rated for 24 bit 192kHz (again, I'm a relative novice with this info, this is just what I'm seeing on the manufacturer's product page). There probably is some practical explanation for why its limited, I'm sure.
For the H95, it is telling me that my max resolution is 24-bit, 48kHz.
However, I still wonder if the DSP might be a bottleneck on these as well. I know earlier Beoplay bluetooth headphones were designed differently and could be driven passively, as was your experience. I also recall reading that the sound signature on some of these headphones (not just Beo, but other brands as well like B&W, etc) would vary quite a bit between when ANC was in use and when it was not-- or maybe it was between BT+ANC and when driven passively.
My best guess is that, by only having one path to the drivers ( DSP > DAC > drivers), it keeps the sonic performance consistent (and provides noise cancellation regardless of input), even if limited by the electronics in the headphones that standard analog headphones do not have. I could be wrong, however.
Anyways. I've been enjoying the APM and the H95 for what they are purpose-built to be-- wireless headphones. I wouldn't mind if there was some headroom for SQ, but I'm not really hurting for it. They've got me listening to music a lot more than I had been in many years, so I can't really complain.
(For fun, I dusted off my Chord Mojo and plugged it in to see what Audio MIDI setup told me about that device capabilities ? This is kind of sad-- I honestly do not have any headphones that are worthy of this DAC.)
Knowing how the AirPods Max work, we know that spatial audio in the Apple Store is going to have to 1) be stereo and 2) be AAC. This means that spatial audio is going to be something like Dolby Stereo, where channels are overlaid with different phase and a DSP, like Dolby Pro Logic built into the headphones (or the player) will decode the signal. I'm betting that this is almost identical to the systems Sony and Bose currently use, and probably very similar to Dolby Pro Logic and DTS Neo:6 as well. It will create a somewhat immersive sound if your personal HRTF matches their standard, and just sound like a weird degradation of the sound if your HRTF doesn't match. A lot of people will be in the latter category, perhaps more than half.
High sampling rates are never going to happen for the AirPods line. But that really doesn't matter because high data rate AAC is audibly transparent. You wouldn't hear any difference between that and 24/96 anyway. The irritating thing is that in some cases, streaming services seem to be unable to downsample high sampling rate audio to something the AirPods Max can handle without artifacts. Yesterday, Amazon Music Unlimited offered HD Audio and Ultra HD Audio for free to the current subscribers to Amazon Music Unlimited. I signed up and tried it with my AirPods Max. It showed that the HD track was bottlenecked down to 24/44.1. In HD Audio there were occasional clicks in the sound, and in Ultra HD Audio, the clicks were constant. I contacted Amazon and got them to switch me back to regular streaming. From what I could tell, the HD Audio tracks were the same mastering as the regular streaming. I listened to several albums I am familiar with, and I couldn't discern any difference. So I guess I really don't care. But that might be a problem with other streaming services where regular streaming and HD streaming isn't separated.
High sampling rates are never going to happen for the AirPods line. But that really doesn't matter because high data rate AAC is audibly transparent. You wouldn't hear any difference between that and 24/96 anyway. The irritating thing is that in some cases, streaming services seem to be unable to downsample high sampling rate audio to something the AirPods Max can handle without artifacts. Yesterday, Amazon Music Unlimited offered HD Audio and Ultra HD Audio for free to the current subscribers to Amazon Music Unlimited. I signed up and tried it with my AirPods Max. It showed that the HD track was bottlenecked down to 24/44.1. In HD Audio there were occasional clicks in the sound, and in Ultra HD Audio, the clicks were constant. I contacted Amazon and got them to switch me back to regular streaming. From what I could tell, the HD Audio tracks were the same mastering as the regular streaming. I listened to several albums I am familiar with, and I couldn't discern any difference. So I guess I really don't care. But that might be a problem with other streaming services where regular streaming and HD streaming isn't separated.
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I still don't understand why there can't be a lightning to lightning cable that can carry audio digitally to the Airpods Max. Fair enough it might not be able to handle the highest res 24/96 files but for normal lossless and even standard audio surely it would make more sense for the wired connection to be fully digital rather than go from digital out from the iphone to analogue via the 3.5mm adapter then digital at the lightning end of the cable
Speaking of the Audio MIDI Setup app... the AirPods Max show up as "2 ch 32-bit Float 48.0 kHz". (Of course they're connected over bluetooth . Just wasn't sure what to make of that.)
Apple wants nothing to do with cables of any sort. They only reluctantly gave an option for wired listening on the APM because of situations like planes. All you have to understand is that Apple hates cables.
This lossless and hi-res offering was simply to keep up with all of the other services for those that want it and have equipment to take advantage of it.
From what I've read, the DAC in the AirPods Max is only designed to work with streaming codecs. It can't handle FLAC or PCM. If it could, you could use a USB to lightning cable to use it as an external DAC, and I don't think you can do that.
The wired option they offer is incredibly convoluted. It has to convert analogue to AAC so the DAC in the AirPods Max can convert it from AAC back to analogue to play in the headphones.
The wired option they offer is incredibly convoluted. It has to convert analogue to AAC so the DAC in the AirPods Max can convert it from AAC back to analogue to play in the headphones.
Ok. Don’t hit me anyone. Not an expert but was just trying things out.
Setup:
2021 iPad Pro -> usb-c adapter -> cable to DAC -> 3.5mm to lightning > APM
played a highres lossless track
The DAC box is capable of high-res.
then switched to wireless with APM, same track
my observation was the wired setup didn’t have a background hiss. The wireless connection did have a subtle hiss.
I assume the background hiss is a result of Bluetooth and other stuff going on.
so much easier to go wireless though. Haha.
Setup:
2021 iPad Pro -> usb-c adapter -> cable to DAC -> 3.5mm to lightning > APM
played a highres lossless track
The DAC box is capable of high-res.
then switched to wireless with APM, same track
my observation was the wired setup didn’t have a background hiss. The wireless connection did have a subtle hiss.
I assume the background hiss is a result of Bluetooth and other stuff going on.
so much easier to go wireless though. Haha.
Did you accidentally hit the noise cancelling off? Another possibility is that the volume level was higher and you were hearing the hiss from the recording itself. Both ways, it's going through the exact same DAC in the APMs, so it shouldn't make any difference. The wire actually has an additional step where it converts from analogue to digital. If one of them was going to be noisier, it would be wired.
You were comparing the same lossless file both times, right? Because lossless can have completely different mastering than lossy.
You were comparing the same lossless file both times, right? Because lossless can have completely different mastering than lossy.
I tried to match volume levels as best I could. Good catch on the noise cancelling. I’ll check that next time.
Do you have a high-res lossless track recommendation on Apple Music?
Yes. Totally get that the DAC in the cable is smashing it all down. Still interesting to see what results I get.
There are three common perceptual errors that can mess up listening comparisons...
1) Level differences: It's very important to match levels *exactly* a difference of as little as 1dB can throw off a comparison. Human ears tend to favor louder sounds in direct comparisons. If one track is slightly louder than the other, it will be perceived as sounding better- fuller sound, more dynamic punch, better soundstage- even if the tracks are otherwise identical. Calibrating with a meter and test tones is the best way to do it.
2) Auditory memory: Human memory for differences between two similar sounds can be as short as a few seconds. If there is a delay of more than that between listening to the two samples, it is pretty much impossible to accurately discern differences. You need to set it up as a direct A/B switched comparison with no delay between samples.
3) Bias: Human beings are subject to unconscious preferences. It's impossible to eliminate the effects of bias without doing a blind comparison. Double blind is even better. It's very likely that your bias is telling you that wired should sound better than streamed over bluetooth. But in this case, the wired one is going through more conversion than the streamed is. And both streamed and wired is passing through the exact same conversion in the headphones.
If I was going to place a bet, I would bet that the difference you hear was due to one or more of these three things. Just looking at the mechanics of it, there is no reason to think that wired would sound any different than bluetooth. I think if you applied controls to your test to eliminate the influence of these three perceptible errors, the differences would disappear.
1) Level differences: It's very important to match levels *exactly* a difference of as little as 1dB can throw off a comparison. Human ears tend to favor louder sounds in direct comparisons. If one track is slightly louder than the other, it will be perceived as sounding better- fuller sound, more dynamic punch, better soundstage- even if the tracks are otherwise identical. Calibrating with a meter and test tones is the best way to do it.
2) Auditory memory: Human memory for differences between two similar sounds can be as short as a few seconds. If there is a delay of more than that between listening to the two samples, it is pretty much impossible to accurately discern differences. You need to set it up as a direct A/B switched comparison with no delay between samples.
3) Bias: Human beings are subject to unconscious preferences. It's impossible to eliminate the effects of bias without doing a blind comparison. Double blind is even better. It's very likely that your bias is telling you that wired should sound better than streamed over bluetooth. But in this case, the wired one is going through more conversion than the streamed is. And both streamed and wired is passing through the exact same conversion in the headphones.
If I was going to place a bet, I would bet that the difference you hear was due to one or more of these three things. Just looking at the mechanics of it, there is no reason to think that wired would sound any different than bluetooth. I think if you applied controls to your test to eliminate the influence of these three perceptible errors, the differences would disappear.
Thanks! Appreciate the post. I’m just going to use APM wirelessly.?I spent way too much time trying this.
Smart - That's really how the APM's were designed to be used.
Don't fight it - just enjoy
There is a wise old saying... "If it ain't broke, don't fix it!"
It's transcoding to AAC on the fly. I ran into a problem with that actually. Amazon Unlimited offered free upgrades to HD audio so I signed up. However when I played a HD track I would hear occasional clicks. When I played an UltraHD track the clicking was all through the song. When I looked at the data on the track being played, it always said 16/48 Apparently Amazon's app was transcoding it, and it was having trouble making it playable, hence the clicks.
Why when I connect lightning EarPods does Hi Res lossless icon appear and play when the max I have it set to is lossless. Wired lightning headphones sound great actually.
I guess it’s placebo and lying to myself bc bluetooth is not compatible with lossless but everything sounds better to me since yesterday on my AirPods Pro.
Should have just gave us Airplay 2-3 for the Max’s. Would have solved a lot of issues for this lossless stuff. My guess is they’re making AirPlay 3 for the new headphones and their lossless tiers.
Off-topic
Just picked up the Qudelix 5K bluetooth/USB DAC ($109.99) – which supports aptX Adaptive, aptX HD, aptX, Sony LDAC Hi-RES, AAC, and SBC codecs – to use with my M1 MBP / IPP 12.9, IPP 12 Max and B&O H95 (3.5mm and bluetooth). Since H95 supports aptx Adaptive, hoping for improved sound over AAC.
Also test listen ALAC Hi Res Lossless downloads since these require an external DAC with H95, B&W P7 wireless, Sony MX3, MX4
Amazon.com: Qudelix-5K Bluetooth USB DAC AMP with LDAC, aptX Adaptive, aptX HD, AAC Dual ES9218p
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