iPad Pro What is the highest quality audio the iPad Pro 3.5mm jack can transfer ?

Discussion in 'iPad' started by TheRealAlex, Jun 9, 2016.

  1. TheRealAlex macrumors 68000

    Sep 2, 2015

    So I was going over the above link thats my cellphone and I see that the 3.5mm jack transfers rates as listed. But I got to wondering Apple is know for music and quality and in particular high quality audio. But I can not find anywhere that states the audio bit rate and kHz that can be transmitted. Anyone have an idea?

    And also is the 12.9 audio bit rate different because there was some talk of it having an audio chip the 9.7 Pro lacks.
  2. McScooby macrumors 6502a

    Oct 15, 2005
    The Paps of Glenn Close, Scotland.
    Freq response is 20-20,000 KHz, so no hi-res here, sooner they get to it the better IMO, iTunes can handle hi-res files, MB can play 24/96 or higher on newer models, b'stards are either being cheap or that better DAC would hit battery life.
  3. Krevnik macrumors 68040


    Sep 8, 2003
    So, the audio jack doesn't transmit at any "rate". It just carries the signal to the speakers in the headphones.

    Things like the audio bit rate and kHz range are all an aspect of the Digital-to-Analog Converter in the phone. The various iPad/iPhone devices should be operating at 16-bit / 48kHz at the DAC, with newer ones supporting 24-bit (although the iPhone 6 seems to only output 16-bits worth of resolution, despite that). The chips themselves can handle 24-bit / 192kHz, but it appears Apple isn't feeding them data at that rate. But the bigger factor in quality of sound is the quality of the DAC, not the frequency specs. Nothing on the Samsung spec sheet actually tells me what quality the DAC itself is (measurements say the Note 5 is comparable to the Air 2 though, with each having slightly different strengths). I wouldn't be surprised if decent external DACs still win here.

    One thing I've never really understood is the desire for 96kHz audio. It doubles the storage space required, and impacts CPU/RAM needs quite a bit. But 48kHz will accurately reproduce sounds up to ~24kHz, well outside human hearing. And outside most speakers' ability to reproduce, or the usual range that music takes place at (50kHz-10kHz, with secondary sounds up to around 15kHz). Sampling faster doesn't buy you anything. 24-bit? Sure. I can buy that there is an effect effect that makes it more pleasant, I'd be fine with that.

    But the main take-away here should be that the spec sheet will not tell you jack about the audio quality. If you want to know about the audio quality itself, how well it reproduces the original signal, you have to read through reviews that do the measurements.
  4. TheRealAlex thread starter macrumors 68000

    Sep 2, 2015
    So with the response provided which are well explained. Seems like eve if Apple dicthes the 3.5mm jack there will not be any audio quality gain because anything more provided than the 3.5mm jack can carry is outside of human hearing.
  5. Krevnik macrumors 68040


    Sep 8, 2003
    Actually, there very well could be. The article on MacRumors itself seemed to suggest that lightning headphones are better. This actually makes sense since the headphones will need their own DAC, and so they can go with a DAC that is matched well to the speakers, or better shielded from interference from other components that could introduce noise to the signal. Or hell, just going with a more expensive, but higher quality DAC with fewer weak spots than what a phone manufacturer has the space for (both in the phone, and in their bill of materials).

    Again, the quality isn't in the spec sheet, but all these things that aren't on the spec sheet. Things like interference, how clean and accurate the analog output is, etc.
  6. McScooby macrumors 6502a

    Oct 15, 2005
    The Paps of Glenn Close, Scotland.
    The issue has nothing to do with 3.5mm Jack not being capable, it is.
  7. DblHelix macrumors 6502

    Mar 19, 2009
    Guess some have never critically listened to hi res audio. The information outside of human hearing help with spatial cues to give space around instruments and to give a more realistic sound field. Personally I prefer DSD as I feel it best represents the warmth of vinyl without the pops and scratches.

    To experience hires get a good dac (ifi idsd micro or nano are both great), the lightening to camera adapter (female usb out), and the onkyo music player and buy the hd pack.
  8. Maxx Power macrumors 6502a

    Maxx Power

    Apr 29, 2003
    Most of that difference you think you hear, I attribute to mastering. For example, I have not heard any DSD releases that were better than XRCDs (try a few). All that ambience and air around instruments, voices are all there in 16 bit XRCDs, because the mastering quality is extremely high. There are a lot of poorly mastered 16 bit, cookie-cutter releases out there, and if you are convinced that they are the pinnacle of 16 bit/44khz, then you really should hear some XRCDs (or any other high quality mastered 16bit discs).

    By the way, I recommend the DacPort series for any computer and iPad based audio playback if you ware into fidelity. There are iPad/iPhone firmwares for the DacPort for high resolution (24/96) audio, if you are into that.
  9. rasputin1969 macrumors 6502

    Mar 4, 2010
    Think of it this way - the 3.5mm jack is the same (only shrunken) as the 1/4 inch jack used in the actual recording studio. You're not going to get more Hi-Fi than that.
  10. Krevnik macrumors 68040


    Sep 8, 2003
    In addition to what Maxx said, how are you reproducing those frequencies when the speakers themselves are not actually able to reproduce the frequencies, and many use a low pass filter to prevent it from doing so?

    Honestly, there are so many things that can be done to improve the listening experience that discussing hi-res audio should be really low on that list.
  11. TheRealAlex thread starter macrumors 68000

    Sep 2, 2015
    Thank you everyone I appreciate the replies. I don't want to go down the rabbit hole of Hi-end audio equipment and audiophiles that's a whole different world for people with disposable income. Not spending $50,000 on speakers here.

    I was really getting at is Apples decision to eliminate the 3.5mm jack it seems like as one person said its just a shrunken down version of the 1/4 jack used by Pros in the Music industry. So reasoning to get rid of it seems to be at least my speculation is.

    #1. Cost the DAC each phone has and its quality can be eliminated. But that cost will be pushed onto the consumer kids will be buying all kinds of USBC or Lightning port external DACs.
    #2. To my understanding Bluetooth Audio unless it's aptX HD is not as high quality as what can be passed via 3.5mm jack
    #3. Real estate getting rid of this long hole basically Apple can add in a bigger battery or another speaker.

    My guess is Apple launches new Digital and Wireless only Beats since they eliminated the Wired Beats Studio 2.0 last week they removed all mention of them from the website and dropped the price from $300 to $149.

    In doing so they launch a new Audio standard similar to the Retina Display catch phrase which worked so well by saying the human eye can not see the pixels.

    Their Audio Catch phrase Might be Auditory Sound meaning it covers the full spectrum of human capability. And is superior to the 3.5mm jack

    I'm just trying to pin down the fact that the 3.5 mm jack is so good it's not even being fully utilized. To its full potential.
  12. zhenya macrumors 603


    Jan 6, 2005
    You're thinking about it wrong. The 3.5mm jack is just a removable portion of the headphone's wire. So unless you are questioning the resolution of the wire itself, there is nothing to see here.

    I think that what Apple is going to do is switch to a combination of wireless/lightning headphones where plugging them in via lightning automatically pairs the headphones and charges them. Apple will probably include an inexpensive version in the box that might be lightning only, with the wireless version being an upgrade purchase, or they'll include the wireless version right in the box that charges from the new USB-c to lightning cable that every iPhone will include in the box. It's also possible that they will announce a new hi-resolution music service that leverages this lightning connection and/or a new higher-bandwidth wireless connection. Even though losing the 3.5mm jack is not technically necessary for such a change, they'll use it as marketing cover for doing so.
  13. rasputin1969 macrumors 6502

    Mar 4, 2010
    Even if Apple kill the 3.5mm jack the iPhone will still need a DAC for the speaker.
  14. Krevnik macrumors 68040


    Sep 8, 2003
    AAC is also a supported codec, although it really only gets up to the same quality as iTunes downloads (meaning using ALAC or FLAC is wasted since it will bring it down to 256kbps). But yes, in that case, the compression is the limiting factor for bluetooth. Lightning very likely just sends PCM digitally, which means no compression, so it wouldn't be the bottleneck.

    This is the main reason, I think. It boils down to: how many people still use it with their phone, versus who would use whatever replaces it. Unfortunately, I'm not helping much, since I don't use headphones except in certain situations (so Apple's getting usage data to that effect). Even less with my iPad. Usually when I am using headphones, my AAC Bluetooth ones are "good enough" because I'm not in an area for very nuanced listening. But when I am, I'm always piping it through AirPlay (external DAC) or through a dock that happens to have an external DAC.

    Another interesting data point is that Bluetooth 5 is coming soon, which if there is a FLAC/ALAC-like codec added as standard, Apple might be willing to jump on board fairly quick (Apple's historically been pretty good with the newer Bluetooth profiles in terms of beating most of the industry to support).
  15. jerwin macrumors 68020

    Jun 13, 2015
    Sure you can. You can use balanced connections.
    But more importantly, a 3.5mm jack is used to drive headphones. To do this with aplomb, it needs to be electrically isolated, and have enough power to drive one's chosen headphones without distortion.

    My favored headphones go deep-- very deep. But some of my devices lack the power to drive it down that low. The end result is that I don't enjoy listening to music on those devices with out some sort of additional headphone amp.

    And that sort of consideration isn't reflected in the "specs" provided to such aggregators as "gsmarena".

    192 khz? Are you a dog?

    24 bit sound? Do you enjoy listening to rockets at close range? Would you like to bring that experience into your anechoic chamber?
  16. cano, Jun 20, 2016
    Last edited: Jun 20, 2016

    cano macrumors newbie

    Jun 20, 2016
    It may fall off the thread a little bit but I didn't found any place on the enterly internet that spoke about it within the last year...

    I found a way to play 24/192, 24/96 and even 32/96 ALAC files directly on my iPhone 5s using the official Apple music app through iTunes.

    Just by renaming the usual extension (in windows) ".m4a" to ".mp4" will trick iTunes giving audio files with unknown sample rate and thus capable of upload those to my device. And play those normally on the iPhone. There is no conversion to AAC done by iTunes as the enterly file weight is conserved.

    I know that even iPhone 6 has a hardware output limited to no more than 16/48 (I think?), but I found it curious that all the forums states that ALAC or even AAC (also tested succesfully by me) higher than 16/48 was impossible to transfer to any iOS device using the official Apple music app.

    The audios are fake PCM oversampled files I created from a 24/96 classical music FLAC I had using MeGUI and xrecodeII.

    Am I doing something wrong perhaps?

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