Apple Music with iPhone and External USB C DAC: Bit-Perfect or Altered Playback?

[im_gumby]

On macOS indeed, but on iOS and iPadOS you can see the DAC switching sampling rate following the content, at least with Apple Music but I guess this is true for any app using standard api.

The different behavior makes sense I guess: on the mobile devices a single app has exclusivity. On the desktop I understand some might be irritated by this fixed sampling rate but it allows to set up a chain with a convolver for room correction with a FIR, and that’s just a use case for us folks, for audio professionals there a plenty of other reasons probably. Personally I am not bothered by this and rely on a good implementation of the SRC.

Up-sampling requires a bit more horsepower... phones are designed to sip power so... ;-)

In terms of sound... depending on the music, source and the quality of your IEMS or Headphones... there's a point of diminishing returns.
With my Alpha, on my Macbook, I can hear a difference when I up-sample to the max of the device. (32/768k) However... its harder to hear a difference if I only up-sample to 32/384k versus the 32/768k. I'm sure others can.

Also I do hear a difference between my iPhone and macbook in terms of sound quality even without up-sampling. The Alpha seems to like having a bit more power which is why it has some issues w some phones and not others. (Some run it w an external battery/power source using an iBasso cable or similar specialty splitter cables. )

YMMV depending on your hearing and quality of your devices.

I apologize since this is getting off topic and beyond the OP's initial question.

Since the iPhone got rid of the 3.5mm headphone jack... you have to use a dongle which does have a dac built in. Amir did a review here and it did well...
You will definitely get better sound (even without up-sampling) using a dongle dac that has either 3.5mm or 4.4mm (balanced) out. You should be able to hear a difference between the 3.5mm and 4.4mm output. ( My Dita Project Ms allow me to switch connectors and I'm sticking w the 4.4mm )

While the Alpha isn't perfect... for $100 or so... best bang for your buck. Reviewers put the iBasso DC Elite above it in terms of sound quality, but its 4X the price.
Note: If you're going to put this in your pocket while you move about... the Apple Dongle is probably the best bet. The USB-C socket is a weak point on these DACs.

 

[antcollinet]

Up-sampling requires a bit more horsepower

Not enough to worry a modern phone.

However... its harder to hear a difference if I only up-sample to 32/384k versus the 32/768k. I'm sure others can.

They can't. Nor can you if the up-sample is done correctly. In fact there is no audible benefit above 24/48. Or at least not that is audible to humans.

Also I do hear a difference between my iPhone and macbook in terms of sound quality even without up-sampling.

That is possible - but if you are, it will be due to lack of level matching or a power limit - rather than any inherent audio quality issue.

 

[im_gumby]

Not enough to worry a modern phone.


They can't. Nor can you if the up-sample is done correctly. In fact there is no audible benefit above 24/48. Or at least not that is audible to humans.



That is possible - but if you are, it will be due to lack of level matching or a power limit - rather than any inherent audio quality issue.

Yup its a power thing.
The Alpha Onix opened up w more power.

I think the big issue is the power difference since the dongle dac is getting its power from the source (pc or phone)
The sound stage seemed wider.

I also think that w the up sampling also helped w a bit more clarity.

I tested w both my Project Ms and I have a M&D MW65 using a 3.5mm connection. There was a greater difference using the Project Ms over the MW65s.
I suspect YMMV depending on the quality and sensitivity of your IEMs/Headphones.

But again, this is all subjective. So take it for what its worth... (Nothing)

 

[antcollinet]

But again, this is all subjective.

Exactly - if you were to carry out the same comparison, but using controlled and blind listening tests those perceived differences would vanish.

 

[bigdewil]

PC + sabaj 2022 dac.

 

[voodooless]

USB is a digital interface

Well, almost the USB-C connector standard also provides for a mode that allows analog stereo output and a microphone input. I have no idea how many devices implement this. Probably not many.

In case of the Apple dongle, it just has the tiny DAC and headphone amp built into the USB-C connector-end of the cable.

 

[antcollinet]

PC + sabaj 2022 dac. View attachment 411577View attachment 411577

That post is not telling most of us here anything

 

[Jimbob54]

Well, almost the USB-C connector standard also provides for a mode that allows analog stereo output and a microphone input. I have no idea how many devices implement this. Probably not many.

In case of the Apple dongle, it just has the tiny DAC and headphone amp built into the USB-C connector-end of the cable.

I had several oneplus phones that allowed that . Since I moved to pixels don't believe they do. Tbh I think I'd always choose a dac dongle with known performance anyway .

 

[ZolaIII]

Reset... The pipeline in OS determines it's output and I don't have clue how it goes on iOS.
If exclusive mode means direct use of OEM or other USB Audio 2.0 driver in this case driver dependant and of course to DAC supported output. If it's seme-exact it's bit perfect but as much as you want it for storage, you don't want it to the analog transceiver's (aka drivers) and room if such. You want to do DSP processing on FP and glue it down (convert) to integer and you won't possible hear more than 19 bit (in mids-uper mids) or 20 KHz. Still it's useful to use higher output; for filters, convolutions and so on for various reasons and motivation (pushing the noise out of range, lower latency and so on).
Internal output to built in speakers is definitely heavily processed or it wouldn't go at all under 100 Hz (which it does).
Not exactly answer any of you hoped for but anyway best I can give you.

 

[TunaBug]

Well, almost the USB-C connector standard also provides for a mode that allows analog stereo output and a microphone input. I have no idea how many devices implement this. Probably not many.

Well I can check the "learned something new" today box. Thanks!

 

[The_Lecht_Rocks]

forgive my ignorance.
I have a bedside headphone DAC / AMP
I previously used lightning to camera adaptor then usbA to amp USB-B in
I now have iPhone 16 with usbC out.
do I need an adaptor or will usbC out offer bit perfect stream to thee amp/dac connected iPhone usbC to amp/DAC usbB in ?

Qobuz is my hires player

 

[antcollinet]

will usbC out offer bit perfect stream

I have no idea.

What I can offer is that "bit perfection" is a vastly over-rated concept, and offers no audible benefit except in the vanishingly unlikely event that any alterations to the bits are done incorrectly.

I don't worry about it. And I'll always advise anyone else not to lose sleep over it either.

 

[The_Lecht_Rocks]

I have no idea.

What I can offer is that "bit perfection" is a vastly over-rated concept, and offers no audible benefit except in the vanishingly unlikely event that any alterations to the bits are done incorrectly.

I don't worry about it. And I'll always advise anyone else not to lose sleep over it either.

Ok. I will “rephrase”…
New Apple iPhone 16. USBC out…. Does it need a “dongle” or adaptor to supply full hires feed to outboard DAC ?

 

[antcollinet]

Ok. I will “rephrase”…
New Apple iPhone 16. USBC out…. Does it need a “dongle” or adaptor to supply full hires feed to outboard DAC ?

Again - no idea. For others who might know, they'll probably need you to state what you mean by "full hi res" - it might be capable of some sample rates but not others.


From my side I'll give you the same as last time. There is no audible benefit to "Hi-Res once you get past 24bit/48kHz

 

[palm]

No dongle necessary. Personally I also stick to 24/48 but higher is possible. I can only speak about Apple Music, you can have different settings for lossless as described in https://support.apple.com/en-us/118295