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Sorry for your loss: iPhone audio life after 3.5mm

  • Will Apple delete the 3.5mm headphone socket from the soon-to-be-announced iPhone 7? That’s this week’s big question. Not only might the new model shed a wafer’s worth of thickness but also micro-grams in weight as its internal DAC and headphone circuit go bye bye.

    “What’s a DAC?” – A question lobbed my way recently by an Apple Store staffer. With the iPhone DAC set to be externalised, a little staff training is in order – and quick smart.

    DAC = ‘Digital to Analogue Converter’. A chip that takes the ones and zeroes from Spotify, Tidal or any iOS-based music app and turns ‘em into an op-amp-ready analogue signal for driving attached headphones.

    A follow up question: will this vanishing act cause fear to turn to loathing? Not necessarily. Options remain even if Apple is jack of our jacks.

    The first is to make use of the iPhone’s Lightning socket which we adapt to USB (and survive) using an Apple-sanctioned accessory. To its business end we connect a AudioQuest DragonFly Black/Red (US$99/$199). Audio is then extracted digitally from the iPhone and decoded/amplified by the AudioQuest dongle itself. The good news, even for iPhone 5 and 6 owners, is the end result will sound quite a bit better than either iPhone’s 3.5mm output.

    Alternatively, those with deeper pockets – both figuratively and literally – might opt for the Mojo from Chord Electronics. At US$599 it is considered by many to be best in its portable DAC class.

    To listen and charge simultaneously we need Apple’s Lightning to USB 3 connector.


    If hardwired adaptors seem like a kludge-y way to continue to use your favourite headphones, or you don’t trust Apple not to eventually have the iPhone sever ties with unofficial workarounds, consider headphones with an Apple-approved inline DAC/amp.

    The Cipher wire that connects Audeze’s (downright thrilling) SINE planars to the iPhone’s Lightning socket hosts a mic-like dongle that handles D/A conversion, bespoke amplification, microphone and playback/volume control.

    You might reasonably ask: why don’t all portable DAC and headphone manufacturers leap aboard Apple’s Made for iPhone’ (MFI) bus? Intellectual property is why. John Franks of Chord Electronics has spoken openly about not wanting to hand over the keys to his IP kingdom in order to be rubber-stamped by Cupertino; a view rumoured to be shared by one VERY large German headphone manufacturer.

    Side note: as owner of Beats, Apple are likely seen by other headphone manufacturers as foe, not friend. It’s entirely plausible that tomorrow’s (Sept 7th) Apple event will see the announcement of new Beats models. If not Lightning-based, wireless.

    And wireless headphones means Bluetooth. The mass market is already way ahead of Apple – wireless headphones now outsell their wired brethren – and audiophiles, many of whom tend to rubbish the sound quality of Bluetooth’s lossy connectivity.


    But Bluetooth audio offers greater stability and better sound quality than it did five years ago. Howevere, full audiophile credibility only really arrives with aptX compatibility. Browse your local hifi store and you’ll see CSR/Qualcomm’s four-letter abbreviation dotted on a number of products.

    aptX’s selling point, one verified by yours truly on numerous occasions with numerous devices, is that it sounds better than the default SBC – known in more technical circles as Low Complexity Subband Coding.

    aptX’s theoretical advantage is a psychoacoustic compression algorithm that juices better sound quality from Bluetooth’s bandwidth. Reality confirms this theory: the aptX-equipped Sennheiser Momentum Wireless sound fuller, tonally richer when Bluetooth-connected to the aptX-equipped Apple Macbook Air than the aptX-absent Google Nexus 5. aptX makes a positive difference to the listening experience but BOTH devices, transmitter and receiver, must be suitably equipped.

    Qualcomm maintain a comprehensive list of aptX-equipped headphones here.

    Experience also tells us that not all Bluetooth headphones sound alike. That’s not Bluetooth’s fault. Inferior drivers, low quality wiring and poor construction erode sound quality more than wireless streaming ever could.

    What about adding Bluetooth reception to an existing pair of headphones? Such dongles aren’t new. Noble Audio’s BTS combines aptX-equipped Bluetooth receiver, DAC and headphone amplifier for US$99. The BTS gets us up and running in the absence of a headphone socket proper.


    Astell&Kern’s latest product, the XB10 (US$189), is almost twice the price of the Noble piece but earns its pricing premium via the inclusion of single-ended 3.5mm and balanced 2.5mm holes; the very same complement of outputs that populate the South Korean company’s range of luxury digital audio players. Joining the headphone sockets around the XB10’s circumferential edge are on/off switching, microUSB recharging socket (for a 5 hour run time) and forward/next playback control.

    Like a slightly pudgier Google Chromecast Audio, the XB10’s topside is subdivided into a four section rocker-switch that handles pairing and volume attenuation. A shirt clip is supplied but I prefer to drop the A&K disc into the nearest pocket.

    XB? Extreme Bluetooth. This puck supports the ‘CD-like’ aptX and the newer ‘hi-res-capable’ aptX HD. Don’t get tripped up by Qualcomm’s marketing spiel: aptX HD can stream up to 24bit/48kHz but not before compressing it to one quarter of the datastream’s original size. Just as aptX is lossy, so too is aptX HD and, once again, realising either’s benefits relies on the paired device (transmitter) being similarly equipped.

    Qualcomm’s semantic obfuscation aside, the XB10 sounds very good indeed. Its notable superiority over the Noble BTS sits predominantly below the waist; there’s a good amount of low-end heft and presence to the XB10’s take on Forward Strategy Group’s techno driven Labour Division.

    Just like headphones, hardware choices matter. It sounds like Astell&Kern paid close attention to amplifier quality in the XB10. That’s how I hear it through the Noble Audio Savant custom IEM.


    To extract maximum performance from the Astell&Kern puck though, to hear it free of the slightly frayed edges and greyed out tonality of SBC streaming, we must pair it with an aptX-equipped device. For those who don’t have the big bucks for a top flight Samsung or HTC ‘droid, the Windows OS-based Microsoft Lumia 550 (US$109) is a very affordable, aptX-enabled option.

    Qualcomm list all aptX-capable smartphones here.

    Notable by their absence are Apple. At time of writing, no iPad or iPhone offers support for Qualcomm’s aptX variants, presumably because Apple refuses to stump up the licensing fee for its iOS-based devices.

    When paired with XB10, the iPhone 5/S and 6/S stream audio using the AAC codec. Howe Gelb’s alt-country rambling sounds perfectly acceptable with my iPhone 6S Plus but the Lumia 550 and its aptX streams are a noticeable step up in terms of the (all-amorphous) listener engagement, especially with Tidal Hifi. aptX realises the XB10’s full potential but Apple doesn’t yet have it running on the iPhone.

    The issue of the hour then isn’t merely the impending erasure of the iPhone’s 3.5mm headphone socket but the necessary addition of aptX (HD) Bluetooth support as compensation.

    Further information: Astell&Kern | Noble Audio | AudioQuestQualcomm aptX



    John H. Darko

    Written by John H. Darko

    John currently lives in Berlin where creates videos and podcasts and pens written pieces for Darko.Audio. He has also contributed to 6moons, TONEAudio, AudioStream and Stereophile.

    Darko.Audio is a member of EISA.

    Follow John on YouTube or Instagram


    1. gave up on iphone years ago and went with android, glad i did. Apple’s software and hardware restrictions are a joke, not to mention itunes–the slowest, most intrusive software ever installed.

    2. Speaking of Android, the Moto Z has *already* lost its 3.5mm headphone jack. There’s a USB Type C port on the bottom, and that’s it. Moto’s phones have been supporting AptX for awhile so there’s no issue with BT phones if you want to go that route. The Z’s modular system also allows for something a bit like what the original LH Geek Wave was supposed to be before they canned it in favor of a standalone DAP.

      Rather than plugging a dongle DAC/amp into the Type C port, you could simply slap an external DAC/amp and headphone jack right to the back of the phone, making it a bit thicker but otherwise no less practical than using the phone naked as it were. Whoever’s the first to market with that will likely do well, assuming the Z series sells in reasonable numbers.

      Apple’s “lockdown” approach is the price of admission, you know that going into it. You use an iPhone how they want you to use it, you use an Android phone how you want to use it, up to and including removing the stock software entirely for your custom ROM of choice. I’m not bothered by that. I do think there has been a distinct lack of vision in the post Jobs era though. Siri is fine, but its objectively worse than both Google Now and even Cortana. Apple Maps of course was an utter disaster at launch, and I’m still not sure if it’s even reached parity with Google Maps. Apple Music doesn’t really do anything that Spotify wasn’t doing already, leading Spotify’s CEO to give his famous “oh, ok” response at launch.

      It applies to the hardware side as well. Apple used to be proud of the fact that they didn’t really do focus groups, they told the public what they wanted. They created the product, and then created the market for it. They don’t really do that anymore. The iPhone 6 Plus is a market reaction to losing sales to big screen Android phones like the Galaxy Note series. The iPhone SE is literally just a relaunched iPhone 5. The iPad Pro is a giant iPad that does what Samsung and Microsoft were already doing, only you have to stick the “pencil” in the bottom to charge it because it needs a battery for some reason. The Apple watch looks like a tiny iPhone instead of a watch, and most people seem to be already bored with it. The software is also a clunky mess compared to what Samsung is doing with Tizen, or even Android Wear for that matter, and most companies are already rolling out their third gen Android Wear devices. Apple has no answer for the Roku Streaming Stick or the Fire Stick. I could go on.

      Apple used to do something, and then it would take rivals several model cycles to be able to catch up. That’s all over. It took Samsung two tries to get their finger print sensor to be as good as Apples, but faster moving Chinese rivals like Huawei didn’t even need that long, and Chinese companies are already building phones with industrial designs as good or better than Apple’s, so that advantage is over, and that’s not to even get into the fact that those companies can charge half as much. They generally aren’t big players in the US…yet…but within a couple of years I’m certain that Huawei and Xiaomi will be as familiar names as Samsung and LG, at the expense of too slow companies like HTC, and perhaps Apple.

      • And look at that, the iPhone 7 is a water resistant iPhone 6 minus the headphone jack. OOOooooo WOW! What WILL they think of next?

    3. You mentioned using Lumia 550 as a source for Tidal HiFi. Is Tidal available as an official app for Windows 10 phone? I don’t recall seeing one. How did you manage to play Tidal on your Lumia 550? Thanks in advance!

    4. I too use the Unofficial Tidal app on my Lumia 650. I was not aware that these Microsoft devices support Aptx. Do i have to do something to stream Bluetooth through Aptx provided the receiver is Aptx capable? Btw, Lumia 650 is not much more expensive – it has an OLED screen too, which might not appear in Iphones till 2017.

    5. Guess I want a reverse XB10… one with a lightning dongle and aptx to the phones. A wired headset connection defeats the purpose of bluetooth

      • Strange, I’d assume wired bluetooth would be exactly what someone invested in head-fi would want. You’d keep all your headphones and just replace the dongle whenever some better standard/protocol came out, as opposed to having the entire headphone at the mercy of Apple/Google’s whims.

    6. I am trying to imagine explaining all of this to my dad/step-mother who just plug their iPhones into the AUX in port on the truck. I won’t have an answer to the question: ‘…so, what’s better about this?’ other than: ‘…just keep the phone you have.’

      • “… just keep the phone you have” seems to be the best option since any true innovation in the smart phone space has more or less ground to a halt in the name of “thinner and lighter” to no particular end beyond winning the spec sheet war.

      • Definitely a continuing market for iPhone 6/s for a while…. or iPods. if you want to stay with Apple.

    7. I think the chances of Apple paying Qualcomm for an aptX license approaches zero. It’s just not worth it since the majority of Apple Music customers couldn’t care less.

      I do think we are going to see more and more headphones come with built-in DAC/amp combos. The Audeze Cipher cable is particularly of note since it is actually a DSP too, and can theoretically do some very interesting things with respect to EQ (whistles and walks away).

      • Especially since it looks like they have custom designed a chip for wireless headphone use. I’m personally hoping for Lighting headphones with DSP built in to be announced tomorrow.

    8. Since I have been using a Dragonfly Red with my iPod two major issues have arisen. First, the stability of the lightning connector is not great and the music frequently stops playing when I am riding my bike with the set-up in my pocket. Then on a couple of occasions I have gone to sleep listening to music through headphones (not while riding my bike!) and have woken to a totally flat battery, presumably because the Fly has drained the battery. Not something that happened with a headphone jack. A concern with the alternative blue-tooth option, assuming quality is OK, is how many times earphones fall out of your ears and you don’t lose them because they are attached to wires…. Do you know people who are always losing their hearing aids…?

    9. So, now that the announcement has come and gone:

      Given that the iPhone 7 comes with a Lightning to 3.5mm adapter, I guess the traditional wired headphone market will remain largely the same? The main difference is that you’ll have a little Apple dongle at the end of your earphones now.

      It will be interesting to see the actual specifications of the W1 chip. My gut feeling: better battery life than Bluetooth, worse fidelity than aptX. I could be wrong – I am just basing this on what seems to be Apple’s general philosophy in regards to this stuff.

      From a business perspective, the main takeaway is that Apple is now licensor of two proprietary technologies for audio products.

      Audeze’s Cipher cable is now officially the most elegant way to hook up a pair of wired headphones to your iPhone 7 (wow – only one cable!) – and so Apple makes more money from tariffs. I think we’ll be seeing a lot more of products like the Cipher soon – but unfortunately not from the likes of Chord (and allegedly… Sennheiser?). But it’s easy to imagine companies like B&O and Bose coughing up for the fee, right?

      I personally wouldn’t want to deal with the dongle > Dragonfly > headphones cable setup every day, but I am thinking I could live with the dongle > cable setup that Apple is proposing. I would also consider buying a hypothetical Audioquest iDragonfly 2, if it doesn’t add much bulk.

      Same deal goes for W1. It will be interesting to see what it offers that would persuade manufacturers to make products that are iPhone-only, rather than the existing universal Bluetooth headphones.

      • RE: W1
        According to Ars Technica, “A quick note on the W1: it’s used to make pairing and battery status checking and the Siri features work quickly and seamlessly, but the actual audio is still being streamed over good-old Bluetooth, and the AirPods can be paired the standard way with anything that will do Bluetooth audio.”

    10. The iPhone 7 announcement had about as much relevance to my life as telling me that the next Jeep models wouldn’t come with ashtrays, but I do think its sad that Apple Corp feels the need to punish their customer base. They seem more intent on building a camera with smartphone functionality anyway – perhaps they should market it as such ?

        • Quite. I would love a 256Gb Touch with an ESS Sabre on board…*sigh*…oh, and it could be fatter to accommodate a larger battery. Are you listening, Mister Cook?

          • +1 to that idea Graham. For the life of me i cannot figure out why (after a certain point) the holy grail of the design has to be wafer thin. It is obvious that battery technology will not catch up for quite some time – so a thicker phone with double (or triple) the battery life would be a great advantage to most all smart phone users (IMO) They could even do as you say adding a quality internal DAC/amp chip rendering all the external extra’s the audiophiles use now superfluous .

    11. It’s an easy one 🙂

      Except for the ‘Third World’ which doesn’t have the money to buy Apple products, the mobile phone market is near saturated, so phone sales are levelling off. Apple phones particularly so as there is more and more good Android phone competition and it is not so ‘restrictive’ as Apple products.

      Apple relies on ‘proprietary’ products to lock customers in. Having locked them in it now relies TOTALLY on selling these ‘locked in’ suckers a new phone every year, and does it quite successfully. But that won’t last forever. EVERY successful ‘now’ company has its ‘time in the sun’ but eventually the sun goes down, which is starting to happen to Apple.

      Astell & Kern? It has never even got started in the ‘real world’. I am the only person I know that has even heard of them.
      A year ago I thought of buying one of their players. But with the rise of good ‘portable’ dacs and things like the Onkyo HF Player software it seemed pointless.
      I already have a three year old iPhone, purchased ONLY as a ‘remote’ for JRiver’s JRemote and as a remote for my Cambridge Audio ‘Stream Magic 6’ as neither JRiver or Cambridge Audio did an Android version at the time. (Though over time it has replaced my old non-smart mobile phone.)

      This Astell & Kern DAC? Not a chance. It is an attempt to assure the ‘survival’ of the tiny A&K company and that’s all. Their players are already fading away, as are the other makes of ‘dedicated’ players because with good ‘plug in’ dacs available for mobiles they serve no purpose and are too expensive for what a phone plus dac can do anyway.

      EVIDENCE? In the UK we have an outfit called ‘Richer Sounds’. It is a ‘high street retailer’ present in most large towns and has been described as “THE MOST SUCCESSFUL RETAILER OF ANYTHING WHATSOVER IN THE UK”. Because in terms of floor area per dollar sales it is number one.

      It sells electronics and nothing else. TVs, AV, HiFi, whatever.
      And in our area of interest, high-quality audio, it goes from Naim and Chord at the high end, down to Creative ‘Sound Blaster’ at the low end.
      IT JUST DROPPED ASTELL & KERN DUE TO DECLINING SALES (which were never high anyway).

      ‘About me’. At home I use a $1000 Cambridge Audio Stream Magic 6 (a combined streamer, internet radio, and genuine USB dac rather than one that just takes USB sticks). I bypass its internal dac and use a $13,000 dCS Debussy dac, direct into a $5000 Naim NAP250 DR power amp, driving $12,000 Tannoy ‘Kensington’ speakers. Software is JRiver using either streaming to the SM6 or direct as a ‘player’ into the USB input of the Debussy.

      Mobile (in my case the car, I don’t walk around in the street listening to music on earphones) I use an iPhone, running Onkyo HF Player, the camera cable, and a Chord Mojo into the aux input of the Burmester car audio system, which was an extra cost option for the car.

      If I take the $1000 combined iPhone/Onkyo HF Player, camera cable, and Chord Mojo indoors and replace the $14,000 combined Cambridge Audiop SM6/dCS Debussy setup with it the result is TOTALLY INDISTINGUISHABLE from that $14,000 setup or from using JRiver as a ‘player’ straight into the Debussy.

      So who needs, or will buy, this A&K dac? Almost nobody. The much more well known Audioquest Dragonfly varieties will be as good or better (though neither are equal to the more expensive and bulkier Chord Mojo).

      If I sound exactly like I do on the ‘MQA’ thread it is because in both cases I am trying to be REALISTIC. I am neither positive nor negative – just real 🙂

        • Some might wonder why I ‘front’ the $30,000 total cost of the dCS dac, Naim amp, and Tannoy speakers with a $1,000 Cambridge Stream Magic.

          It’s because after 35 years professional ‘technical’ employment in the computer business and an even longer interest in HiFi I actually KNOW that ‘bits are just bits’ and that ‘sound quality’ doesn’t start until the signal is approximately half way though the dac when it gets converted to analog.

          (I could elaborate on this but it is wildly off topic :))

          • Mark – if you think ‘Bits are just bits’ that’s fine but that runs contrary to much of the coverage on DAR. Perhaps your interest in audio might be better served by a different audio site.

            • Why?
              I ‘discovered’ this site recently via a link on ‘Computer Audiophile’ where they were discussing your MQA comments.
              And have found it most interesting. But I have restricted my comments to just two threads as being ‘new’ I don’t want to comment on everything though I have read far more subjects than the two I have commented on.

              And I did state that I did not want to elaborate as it is off topic. So I am not going to elaborate unless you ask me to.

              However, I would like to put my ‘position’ as briefly a I can with just one example:
              There is one very respected and well known professional audio designer (and respected by me too) who said this, when talking about computers, not DACS, and the USB interface:
              “The slope of the leading edge of the pulse is important as it is the detection point for a zero or a one. Thus a very accurate reference voltage is needed so all pulses are detected at the same point on the slope or jitter will be increased”.

              1) It is total nonsense as the computer has an internal clock that is applied to every process. The only inaccuracies from one part of the computer to another part are because of varying wire length and are incredibly small, though the overall clock rate is not particularly accurate.
              This is KNOWN and computer designers have overcome it, right from the worlds first digital computer in 1943. How? By measuring where the MIDDLE of the pulse is expected to be. They don’t use the leading or trailing edges at all so their slope is of no importance. This makes his ‘accurate reference voltage of no account either.

              2) USB. USB uses NRZ(I) coding so ‘statistically’ half the pulses won’t have leading or trailing edges anyway. There are NO gaps between the pulses and if the present one is the same value, say ‘zero’, as the last one the voltage reverses, and if it is a one where the previous pulse was a zero the voltage stays the same. So they MUST detect at the ‘expected’ center or computers would not work at all. (NRZ or NRZInverted coding is used a lot in computer internals, it is not just USB.)
              And this is how they ARRIVE at the DAC input. But NOTE that the ‘expert’ I was quoting was talking about the computer, not the dac.

              It is a case of “a little knowledge is dangerous”. I don’t expect these people argue with their brain surgeon or airline pilot so why argue with computer professionals?

    12. im interested in the difference in sound quality between the xb10 and the dragonfly red… amping characteristics would helpful too. care to share?

      • Go on, just buy the Chord Mojo 🙂

        I have no connection with Chord or any other manufacturer nor with any ‘audio’ website or magazine.

        • I can’t speak for Nicolas but I will never buy the Chord; for that sort of money, I will go a little further and buy a decent powered, desk-top DAC/Amp.
          For portable use my DF Red is quite superb and beautifully untangles even the densest orchestral work.

          • Of course – it’s matter of personal choice.

            I purchased the Chord ONLY because my local dealer (with branches throughout the UK) for both Audioquest and Chord did not have the Audioquest Red in stock and neither did they have it in their ‘central warehouse’. Apparently it has been selling so well they are waiting for receipt of more ‘Reds’ from Audioquest.
            I wanted it for use in the car, connected to the car audio system. I have zero interest in using it on headphones while walking around so its larger size compared to the Audioquest did not matter. And in a car you cannot make full use of the Chords superior performance. so had the Audioquest been available I would have purchased that but patience (equals waiting an unknown number of days/weeks or buying over the internet) is not one of my virtues.

            “Go a little further….”

            That is the problem. How much further? You GENUINELY won’t get a better DAC for less than 15,000 dollars. By ‘better’ I mean ‘accurate’, which is the definition of ‘High Fidelity’. which does NOT mean “I happen to like the sound it makes”.

            Just like my 13,000 dollar dCS Debussy it has NO sound or ‘character’ of its own, but is totally transparent. I put this down to that neither uses a typical 5 or 10 dollar ‘off the shelf’ DAC chip as its central core. Both Chord and dCS use their own digital to analog conversion methods and filters rather than implement someone else’s, such as Sabre’s, Wolfson’s, etc. ideas as best they can and add 500-10,000 dollars or whatever to the price of the ‘budget bought in chip’ originally designed for televisions, DAB radios, etc.

            As neither have any ‘character’ of their own the Chord and dCS are indistinguishable from each other. Bear in mind that the closer you get to GENUINE High Fidelity the closer to each other in sound quality ‘HiFi’ boxes SHOULD become.

            Disadvantages of the Mojo as a desktop or ‘main’ DAC? It gets hotter than most people would like when simultaneously charging and using, which is what you are likely to want to do in a home system. So much so that I would not leave it both switched on and charging 24/7.

    13. If it sends people to sleep – fine 🙂

      Believe it or not I was trying to be ‘helpful’ by giving my reasons behind the HiFi purchasing decisions I make. And I am genuinely amazed by the Mojo, which was NOT what I went into the shop for, intending to buy the Audioquest Dragonfly Red, which they didn’t in fact have in stock.

      I bought the Mojo unheard, on the strength of reviews, including yours. And it turned out to be the most cost-effective HiFi purchase I have ever made. I genuinely believe there is no more accurate DAC on the market, though it may have one or two equals, dCS and MBL come to mind, neither of which have a ‘budget off-the-shelf dac chip’ as their core, and the Mojo doesn’t either. In some ways Chord is now competing with itself.

    14. So, if iPhone had aptX support, you honestly would load it with lossless files and listen it in metro or on the street? or at home? Really?
      If not, all what’s needed is AAC support, that’s all. Snake oil is not needed, even for “audiophiles “, aptX will not sound any better than AAC, if original is AAC from iTunes store.

      • AAC may or may not sound better than aptX. We’ll only know for sure when receiver devices come to market with AAC support included.

    15. Let’s be clear – in reality it’s pretty obvious that Apple positions iPhone mostly as a device for playing content from their store, that is AAC 256. It appears that this bitrate AAC can be directly transmitted to headphones without any transcoding, and if that’s true then nothing can possibly sound better. AptX would have one more transcoding, and could at best sound as good as AAC, never better.
      Only one thing, Apple’s AAC is VBR, so theoretically at most difficult passages bitrate could go too high to be transmitted via BT, and then AptX indeed could be better, but nobody has claimed this to happen.
      So, given all available information, AAC appears to be the best option for Apple phones, for the intended source. I can totally understand their decision to ignore AptX on their phones, but I cannot understand Sennheiser leaving out AAC on Momentum.

      • Very nicely explained. And yes, the Momentum’s AAC omission is baffling. But could also be a licensing (fee) issue.

    Wyred 4 Sound ready SX-1000R monoblocks

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