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USB-IF Publishes Audio Over USB Type-C Specifications (anandtech.com) 135

An anonymous reader quotes a report from AnandTech: The USB Implementers Forum this week published the USB Audio Device Class 3.0 (direct download) specification, which standardizes audio over USB Type-C interface. The new spec enables hardware makers to eliminate traditional 3.5mm mini-jacks from their devices and use USB-C ports to connect headsets and other audio equipment. Makers of peripherals can also build their audio solutions, which use USB-C instead of traditional analog connectors. Developers of the standard hope that elimination of mini-jacks will help to make devices slimmer, smarter and less power hungry. As reported, the USB Audio Device Class 3.0 specification supports both analog and digital audio. Analog audio is easy to implement and it does not impact data transfers and other functionality of USB-C cables since it uses the two secondary bus (SBU) pins. The USB ADC 3.0 defines minimum interoperability across analog and digital devices in order to avoid confusion of end-users because of incompatibility. In fact, all ADC 3.0-compliant hosts should support the so-called headset adapter devices, which allow to connect analog headsets to USB-C. However, digital audio is one of the primary reasons why companies like Intel wanted to develop the USB-C audio tech on the first place, hence, expect them to promote it. According to the USB ADC 3.0 standard, digital USB-C headphones will feature special multi-function processing units (MPUs), which will, to a large degree, define the feature set and quality of headsets. The MPUs will handle host and sink synchronization (this is a key challenge for digital USB audio), digital-to-analog conversion, low-latency active noise cancellation, acoustic echo canceling, equalization, microphone automatic gain control, volume control and others. Such chips will also contain programmable amplifiers and pre-amplifiers, which are currently located inside devices. Besides, USB ADC 3.0-compatible MPUs will also support USB Audio Type-III and Type-IV formats (the latest compressed formats), but will retain compatibility with formats supported by ADC 1.0 and 2.0. Finally, among the mandated things set to be supported by USB-C Audio devices are new Power Domains (allows devices to put certain domains in sleep mode when not in use) as well as BADD (basic audio device definition) 3.0 features for saving power and simplified discovery and management of various audio equipment (each type of devices has its own BADD profile).
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USB-IF Publishes Audio Over USB Type-C Specifications

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  • by Anonymous Coward on Friday September 30, 2016 @05:42PM (#52991909)

    DRM...

    • Oh FFS give it up. This has nothing to do with DRM. The USB-IF is not some media company. The analogue hole is not something that can be patched for headphones EVER. And the purpose of this standard is to output ANALOGUE audio on the USB jack.

      Now stop frothing at the mouth and start thinking constructively.

      • by Anonymous Coward

        Except you'd be wrong...

        Headphone jack and its relation to the DMCA and other laws [boingboing.net]

      • by Anonymous Coward

        And the purpose of this standard is to output ANALOGUE audio on the USB jack.

        You didn't even read the summary much less click through to anything. "digital audio is one of the primary reasons why companies like Intel wanted to develop the USB-C audio tech on the first place" and "host and sink synchronization (this is a key challenge for digital USB audio)".

        "key challenge" == DRM

        HTH. HAND.

  • Now seen as innovative.

    • Nah, not innovative at all. Companies have been locking in their users and forcing unpopular decisions on them for years before Apple made it popular.

    • by cheesybagel ( 670288 ) on Friday September 30, 2016 @08:31PM (#52992523)

      Innovative my ass. Nokia and Sony Ericsson were combining everything in the same port years before: Pop-Port [wikipedia.org], FastPort [wikipedia.org].

      And guess what it sucked and having a separate 3.5mm audio jack was considered a huge improvement.

      Back then it was considered to be a way to force people to buy their accessories and a cash grab. Now Apple calls it "courage". Hah.

      • Explain to me how Apple removing the 3.5mm TRS headphone jack from the latest iPhone is a "cash grab" when the adapter for 3.5mm TRS output is included with the phone?

        I could see your point if the TRS jack was missing from the iPhone AND the adapter for a TRS output was available only with an Apple adapter at additional cost but, since the adapter comes with the phone then I'm failing to see the money grab aspect here.

        I'm an Apple user, I'm typing this on a MacBook Pro and I own three iPods, so perhaps I'm

        • Nokia and Sony Ericsson typically included headphones with their devices. The problem was when you needed a replacement. $$$. Oh and forget charging and connecting the headphones at the same time. And yes we had Bluetooth headsets back then as well. They still suck.

    • This is the third revision of USB audio. USB headphones have been available for a long, long, time.
  • Thin sucks (Score:5, Insightful)

    by PopeRatzo ( 965947 ) on Friday September 30, 2016 @05:51PM (#52991963) Journal

    I'm sitting here looking at my nice Nexus 5x phone, that has a perfectly good 3.5mm jack on it. If I lose my earbuds, I can walk into most any store and buy absolutely adequate replacements for $10 or less. The Nexus 5 is already so thin that it felt funny in my hand and I had to buy a case for it that makes it thicker.

    You think USB-C headphones that "will feature special multi-function processing units (MPUs)" are ever going to be $10?

    • by Anonymous Coward on Friday September 30, 2016 @05:58PM (#52992001)

      Yeah. Those fucking losers can tear my old world G3 Mac from my cold dead hands. I'll never give up SCSI, ADB, or floppy drives!

      • You're comparison makes little to no sense. Par for the course of AC of course.
      • Yes it's better to use the newer Appletalk port than the older Ethernet port. Right? Right?

      • The simpler an interface is, the more useful it is to keep it around. RS-232, LPT and analog jacks are much more useful for tinkering than any of those you names.
    • perfectly good 3.5mm jack

      You say perfectly good, I say horrible. I use a Bluetooth adapter (under $7 on Amazon, one of the best electronics devices I've ever bought) in my car.. It uses a wire with 3.5mm connections on both ends in between the main electronics chunk that plugs into the USB port in the car (so it has no batteries to charge).. The headphone jack connections get flaky, so I have to wiggle/twist them.

      It's not unique to this device either, it's definitely happened to my iPod & iPhone conn

      • What's easier to use? Connecting a wire, or going through menus to setup the Bluetooth headphone, charging batteries, etc.

        What's more secure? What's harder to intercept?

        You figure it out.

        • But I showed you how 'connecting a wire' isn't as foolproof as you think it is.

          Plus, using Bluetooth, after setting it up ONCE, is really easy. It auto-reconnects to my car the vast vast vast majority of the time (literally 2-3 times ever it hasn't reconnected).

          For my cheap Bluetooth headphones, I usually go through the menus, just so I don't accidentally do the dial (which IIRC is 3 button pushes or something)... but that's a problem with those specific headphones IMHO..

          • All you "showed us" in text... was that you buy cheap shit, then act surprised when it's cheap shit

          • by anegg ( 1390659 ) on Friday September 30, 2016 @09:16PM (#52992655)
            Yes, an already-paired Bluetooth connection is easy to set up. Too easy. My wife pulls up in her car next to mine, and all of a sudden I can't hear my phone call anymore, because my phone has paired automatically with the Navigation system in her car and stolen the audio input/output away from my phone. Ok, it doesn't happen that often. But its annoying when it does. My 3.5mm jack never does that.
      • BTW, I'm not saying you have to buy expensive headphones either. I have what are to me perfectly usable Bluetooth headphones that were $20. (I also had previously bought ones that _looked_ like the old iPhone earbuds with just a wire between them, and 2 of them broke within weeks.. they were crap)

        Yes, and it's very difficult to identify the crap from the cool at the counter. Besides, when you buy new analogue wired headphones, you are buying electronics. When you buy new Bluetooth headphones, you're buying electronics plus microelectronics plus Li battery. Suddenly, the lifespan of the solid state microelectronics is reduced from decades to three or four years (battery degradation) and if any fault occurs in the speaker coil/cone, the microelectronics are immediately rendered useless for most consum

      • Re:Thin sucks (Score:4, Insightful)

        by swb ( 14022 ) on Saturday October 01, 2016 @06:51AM (#52993711)

        I'm 50 years old and have owned 3.5mm jack devices for about 40 of those years, starting with a Radio Shack pocket AM/FM radio, a good half dozen or more Walkman-style cassette players, most iPhone models, 3 iPods, and various PCs and laptops. Possibly 2 dozen devices added up.

        I think I've had problems with 1-2 of the cassette Walkman devices and the headphone jacks getting static problems, but the others have been fine and never developed problems. The Walkmans mostly likely became problems because they just got used hard, jammed into pockets with stress on the jacks.

        But I also wouldn't write off general improvements in construction of the jacks since then. We call it the 3.5mm jack like it hasn't changed, but over time everything about it has probably improved. Superior metallurgy means superior contacts with more durable spring force, more resistance to corrosion, engineering improvements in mounting such as tighter, closer tolerance mounting resulting in strain transferred to the housing and not the PCB.

        IMHO, Bluetooth hasn't improved at all other than perhaps slightly on the audio quality side. Pairing is still a PITA, source devices are prone to wandering and shifting to other devices -- I've lost connections on my phone when the headphones in my car were still on, causing my phone to shift to my car headset despite me actively using a headset in the house.

        Then there's Bluetooth's general limitations -- I've yet to see simultaneous pairing with a BT headset where you can get simultaneous mixed audio from two devices -- ie, why can't I pair my PC and phone at the same time and get audio from both in my headphones at the same time? Why do I have to fuck around disabling BT on one to shift the device to the other?

        • IMO, Bluetooth would me a lot more usable if it allowed many:1 pairings. Like in my car, I have some 4 devices that can be paired to Bluetooth. Sometimes, I go out w/ both my phones, but only one of them is connected to the car navigation system. Or say I took my iPad and wanted to listen to a playlist, but let my phone interrupt it if a call came through - that's not possible. Similarly, at home, I have a bluetooth speaker that can be connected to either of my tablets - I'd like it if they could be con

          • by swb ( 14022 )

            I completely agree that bluetooth is feature poor.

            Receivers should be able to mix multiple senders, and senders should be able to handle multiple receivers. How complex you want to make the mix controls would be up to the maker -- tiny headphones, straight up equal mix of all paired devices. A phone or larger device with a user interface? Custom levels, balance, mute, etc.

            Bluetooth now is primitive. I suppose I should categorize it as a miracle technology and be glad it works at all but really it's clu

      • You say perfectly good, I say horrible...

        I say, "Here's someone who doesn't know that this [wd40specialist.com] is a thing, apparently."

    • You think USB-C headphones that "will feature special multi-function processing units (MPUs)" are ever going to be $10?

      absolutely! it will be as soon as nobody wants to buy USB-C shit.

    • by jrumney ( 197329 )
      I think the real motivation is not to make it thinner, but to get an extra 5 minutes of battery life by using the extra 1/32 in saved for a marginally bigger battery.
      • by jrumney ( 197329 )
        That should be cu. in. Why do I see trolls posting Unicode spam, while serious commented have it filtered out?
        • Why do I see trolls posting Unicode spam, while serious commented have it filtered out?

          Î dön't knòw.

      • I think the real motivation is not to make it thinner, but to get an extra 5 minutes of battery life by using the extra 1/32 in saved for a marginally bigger battery.

        Then why not make it 0.5mm thicker and accomplish the same thing?

    • by Anonymous Coward

      Stop looking at it in terms of ease of use, and flexibility. Instead what Apple did is give you a purpose in life, that purpose it running around charging batteries. And its an important purpose, because once a rechargeable has been left at zero for too long, it will never recharge.

      And when the battery is built into a device, the device dies.

      So you are a giver of life when you keep those rechargeable batteries charged! And now Apple and USB-C mean you have a new battery in your wireless headphones to charge

    • You think USB-C headphones that "will feature special multi-function processing units (MPUs)" are ever going to be $10?

      This is just people jumping on the the Apple bandwagon :( shame it's the USB community this time

  • Apple says (Score:5, Funny)

    by JustAnotherOldGuy ( 4145623 ) on Friday September 30, 2016 @06:23PM (#52992099)

    Apple: "We're removing the USB jack from our phones. Wait, we never had one? Okay, FINE, we'll remove the Lightning connector, wiseass!"

    • Apple will probably be all over this for their single usb-c port macbook. But you'll need an adapter to charge and listen at the same time and a dongle to use your lightning headphones you bought for your iPhone!

      • Apple will probably be all over this for their single usb-c port macbook. But you'll need an adapter to charge and listen at the same time and a dongle to use your lightning headphones you bought for your iPhone!

        I hope it'll cost at least $300 per port or I won't feel like I'm getting my money's worth.

    • Okay, FINE, we'll remove the Lightning connector, wiseass!

      If they really wanted to be courageous, they should have just moved to wireless charging only and Bluetooth is still just fine for audio.

      • Or they could have decided not to do such a blatant money-grab and just left the perfectly-working headphone jack where it was. Wireless charging would be fine, but the headphone jack removal was pure crap. More batteries to die, more pricey gadgets to buy, and all for no good reason.

  • No really, I'm quite happy with my 3.5" port which is on my PC, PS4 controller, ipad (currently....) old spare phone, etc.

    Hell, I was trying to figure out how to wire one of these up for my deskphone at my old job
    https://ae01.alicdn.com/kf/HTB... [alicdn.com] when I worked in a job with a fair few support calls, so I could go from music to phone call, simply by moving a cable and answering the phone.

  • You could put a 2.5mm jack in there for audio instead of relying upon an 8.4mm x 2.6mm jack which takes up far more actual physical space than even the 3.5mm diameter plug it wants to so badly replace.

    • Re: (Score:3, Insightful)

      by Anonymous Coward

      It's about DRM

  • by JustNiz ( 692889 ) on Friday September 30, 2016 @06:47PM (#52992213)

    from here:
    http://ww1.microchip.com/downl... [microchip.com]

    "The SBU wires are lower speed signal wires that is allocated for Alternate Mode use only. USB Power Delivery is required for Alternate Mode negotiation before these pins may be used for any purpose".

    Doesn't sound like headphone power-level or analog to me.

    • Doesn't sound like headphone power-level or analog to me.

      Well, son, maybe you should try the specification [those.ch].

      A DFP [Downstream Facing Port] that supports analog audio adapters shall detect the presence of an analog audio adapter by detecting a resistance to GND of less than Ra on both A5 (CC) and B5 (VCONN).

      That summary lied to you. HTH, HAND!

      • The page 167 of the spec is saying that Left ch. (tip of the phone plug) is connected to Dn (A7/B7), and Right ch. (ring 1) is connected to Dp (A6/B6).
    • The SBU wires are lower speed signal wires that is allocated for Alternate Mode use only.

      Yeah who'd have thought that a document that was published 1.5 years ago disagrees with a new specification that was only published this week.

      Clearly the new specification must be wrong.

  • by ArylAkamov ( 4036877 ) on Friday September 30, 2016 @06:49PM (#52992229)

    Anybody know the mean time between failure for these plugs (The micro ones)?

    I've only had a headphone jack fail once, due to some pocket lint getting in the hole, which I was able to remove.

    I've gone through a number of cords and a few devices due to failure of the cord, failure of the female plug, or the female plug becoming so fatigued the solder broke attaching it to the PCB.

    The 3.5mm jack is pretty solid when it comes to abuse. I've accidentally broken off USB connectors several times.

    • USB-C is pretty durable. It's what USB should have been from the start. If you use USB-C for a while and you go back and use a Micro-B you'll be astounded at the difference in quality of connection and how mushy and unsure Micro-B is. For a small connection USB-C is pretty damn durable and reliable.

      • by strstr ( 539330 )

        On my LG G5 is seems pretty flimsy. The connector is lose and wobbly after only using it when charging once or twice a day. Lightning seems better really. :)

    • I've accidentally broken off USB connectors several times.

      MTBF figures are irrelevant given your statement. The USB micro connectors have a very similar PCB level footprint as small 3.5mm jacks. Reliability comes down to how they are designed and how they are implemented. You managed to break off a USB jack? Well given that the body of the jack was primarily designed to be soldered directly to a large plane of a PCB I'm going with crap soldering practices, incorrect board design, or most likely a really crap cheap Chinese USB connector.

      Now internal failures on the

  • by Namarrgon ( 105036 ) on Friday September 30, 2016 @07:22PM (#52992339) Homepage

    It opens a lot of possibilities. Standardised docks, single-connection car charging+audio, powered Bluetooth receivers, that sort of thing. It's a great option to add to our toolset.

    But only as an option - not if it means removing the headphone jack too. If it catches on, everyone starts using USB headphones and audio jacks fall out of favour, then we can talk, but it's insane to remove such a popular connector while it's still so wisely-used.

    • by jrumney ( 197329 )
      Docks and car kits can already play audio over USB if they want to using existing standards. It doesn't even need to be USB-C. Only analog audio for dumb, unpowered headphones needs a new standard if it is going to go through the extra pins on a USB-C connector.
  • by Anonymous Coward

    "Developers of the standard hope that elimination of mini-jacks will help to make devices slimmer, smarter and less power hungry."

    Less power hungry? Sounds like bullshit. Could someone explain how?

    • by jenningsthecat ( 1525947 ) on Friday September 30, 2016 @08:15PM (#52992479)

      "Developers of the standard hope that elimination of mini-jacks will help to make devices slimmer, smarter and less power hungry."

      Less power hungry? Sounds like bullshit. Could someone explain how?

      Because of the lack of a 3.5mm standard jack, more users will choose NOT to play music on their devices. This results in less usage of the audio amplifiers that feed signal to earbuds and headphones, resulting in less power use overall. ;-)

      • by jrumney ( 197329 )
        And fewer music tracks ripped from YouTube, which should help the music industry...wait a minute, why are our profits going down when we cut piracy by making it more difficult to listen to music on mobile devices?!
    • Not only the device will have to support multiplexing, DRM, power management, protocol negotiation, DRM, compression, encryption, DRM, delivery of power to the external amplyfiers, DRM... it will also have to still support the analog audio option. So the "less power hungry" claim is bullshit.

      I'll concede that the "slimmer" claim is realistic, given that two connectors take less space than one. But in a time when phones are getting larger and larger, I don't think this is going to solve anyone's problem.

  • a lightning connector isn't totally bad, because it's the same size but thinner than a headphone jack. but USB-C is a pretty clunky little cable port/connector, twice the width of a headphone connector or lightning connector. it also fits loosely and wiggles really easy, and the connector and port both bend easier.

    lightning and headphone jacks by contrast both fit really snuggly and feel secure.

    the USB-C port on my LG G5 is already wiggling and wobbly after just a few months light use.

    • by strstr ( 539330 )

      and that's after using the USB-C only once a day for charging! think about the madness and wear/tear of unplugging/plugging in headphones into the USB-C port all day- the wear on the headphone connector, and the device itself.. they should switch over to lightning style USB to get rid of the huge connector/port and more snug build.

  • Is it really that much trouble to have an extra port or two on a phone? Especially nice if one pooped out for whatever reason...imagine if that became standard.
  • by NotInHere ( 3654617 ) on Friday September 30, 2016 @11:46PM (#52993081)

    No mention of vorbis, flac, alac or opus. Great, isn't it?

    PCM_IEC60958
    AC-3
    MPEG-1_Layer1
    MPEG-1_Layer2/3 or MPEG-2_NOEXT
    MPEG-2_EXT
    MPEG-2_AAC_ADTS
    MPEG-2_Layer1_LS
    MPEG-2_Layer2/3_LS
    DTS-I
    DTS-II
    DTS-III
    ATRAC
    ATRAC2/3
    WMA
    E-AC-3
    MAT
    DTS-IV
    MPEG-4_HE_AAC
    MPEG-4_HE_AAC_V2
    MPEG-4_AAC_LC
    DRA
    MPEG-4_HE_AAC_SURROUND
    MPEG-4_AAC_LC_SURROUND
    MPEG-H_3D_AUDIO
    AC4
    MPEG-4_AAC_ELD

    • So what?

      Currently in order to support any of these standards for output to headphones, you need to decode to PCM in the CPU, and then send it to the DAC for playback. It seems to me that won't change here -- you'll still be able to playback all of your Vorbis files via USB-C digital audio; you'll just have to decode to PCM first and then output the PCM.

      Sure, that means that you won't be able to offload the decoding to your headphones or an external audio receiver, but that's already the situation we have f

      • So what?

        So what is why support any of those formats? Why not just PCM in the first place?

        • So what is why support any of those formats? Why not just PCM in the first place?

          Because for something like a cell phone, decoding DTS-III in CPU would be very demanding and would drain your battery pretty damn fast.

          There will also be a certain amount of savings in needed bus bandwidth, especially for multi-channel audio. Decompressing a 5.1 or 7.2 stream into its components and then sending it across the bus would be very bandwidth intensive, and may have an impact on other USB devices on the same bus (or the other devices might have an impact on the digital audio). Vorbis, ALAC, and

          • Because for something like a cell phone, decoding DTS-III in CPU would be very demanding and would drain your battery pretty damn fast.

            So put it in the audio codec, then pipe the decoded output to the device.

            • Because for something like a cell phone, decoding DTS-III in CPU would be very demanding and would drain your battery pretty damn fast.

              So put it in the audio codec, then pipe the decoded output to the device.

              Which part of "decoding DTS-III in CPU would be very demanding" didn't make sense?

              I'm not aware of a cell phone that has DTS-III decoding hardware built in; you'd have to do it in software. That's the "codec" part, and that's the part that will put a lot of demand on the CPU to decode.

              You could put decoding hardware in the phone for each of those audio formats, but it's going to be easier to offload that to the device instead. Phones are already pretty crammed for space on the logic board; adding more chi

              • You could put decoding hardware in the phone for each of those audio formats, but it's going to be easier to offload that to the device instead.

                It's not going to consume less electricity if you put it in the audio device instead of in the mobile device.

                • It's not going to consume less electricity if you put it in the audio device instead of in the mobile device.

                  It does when it means the difference between decoding in software on the mobile device on the primary CPU versus decoding in dedicated hardware in the audio device itself.

                  Hardware decoding is always more efficient than software decoding on a generalized CPU.

                  Yaz

                  • It does when it means the difference between decoding in software on the mobile device on the primary CPU versus decoding in dedicated hardware in the audio device itself.

                    Yeah, so put it in the phone in hardware. Also, the user also has to pay for that external decoder. Also, in practice, one that does all those formats is likely to need a full-fledged processor onboard anyway. If it doesn't do all those formats it's likely to not have the one you want...

                    • Yeah, so put it in the phone in hardware. Also, the user also has to pay for that external decoder. Also, in practice, one that does all those formats is likely to need a full-fledged processor onboard anyway. If it doesn't do all those formats it's likely to not have the one you want...

                      As you either have reading comprehension or memory problems, I'll just quote back from what I typed previously in this thread:

                      You could put decoding hardware in the phone for each of those audio formats, but it's going to be easier to offload that to the device instead. Phones are already pretty crammed for space on the logic board; adding more chips (or processor circuitry) to decode all of those formats in hardware would be sub-optimal. It's better to leave this to the audio device on the other end of the USB-C connection.

                      Yaz

                    • Sigh. You certainly wouldn't need another whole chip, so even mentioning that is literally retarded, or an attempt to derail the conversation. There is ALREADY format decoding in the audio CODEC, which is ALREADY integrated into the SoC and not on a separate chip. Audio decoding likely goes to the CPU sometimes for heavy lifting, but modern cellphones can ramp up a single core at a time (this should not be news to you) so doing that will not immediately punch your battery in the nuts. The additional real es

    • by jrumney ( 197329 )
      Noone is going to use anything other than PCM for stereo anyway, and if it's multichannel, they will jump straight to DTS, maybe some of the new MPEG4 standards if they take off. Why they have other lossy codecs on there, especially MPEG1 layer 1, is anyone's guess. Probably they took a list from the Blu-ray standard or somewhere, which included backwards compatibility with DVDs, CDs, and because Sony was involved, Minidiscs as well, and said "we have to have these".
      • With the exception of PCM (And possible MAT, I've never heard of that one), every one of those codecs is patented in some manner. I suspect that might be part of the explanation: A lot of companies trying hard to make sure that their patents are required in some manner, to keep the licensing money flowing in.

  • by nateman1352 ( 971364 ) on Saturday October 01, 2016 @01:44AM (#52993281)

    Now before anyone freaks out, keep in mind that there is nothing in the Audio over USB-C spec that requires the device that implements it to not have a headphone jack. Its totally legit for a phone to support this spec and have a headphone jack. In fact, I suspect that most vendors will probably go this route.

    Being able to plug your phone in to a single USB-C connector on your car or stereo and have it charge the battery and play music using 1 wire is a nice feature.

  • by Anonymous Coward

    If the same analog audio is delivered, I don't see how it could use less power than a jack socket.

    And is it really a complete replacement? Can you still use the cable as an FM antenna?

  • Any word on how this might affect / conflict with Overbridge [elektron.se] multi-channel audio signal and production / presentation metadata over USB?
  • In reading the summary I got the impression that they were going to use the low speed data lines on the USB-C connector as analog output lines. That would make more sense to me than defining some new audio device standard. I thought the USB 2 spec contained enough audio device standards to satisfy any kind of headphone setup people might use on a phone, music player, computer, or whatever else someone might expect to find a USB-C port. With USB 2 data pins being a common and required part of any USB-C alternate mode I'd think that creating a device capable of plugging into a USB-C port and providing audio input and/or output would be trivial and essentially a solved problem. USB 2 is certainly capable, as far as I can tell, of providing multiple audio channels with high fidelity without running into issues of bandwidth or power limits. Perhaps I'm missing an important detail.

    I never was a big fan of USB. I thought the spec always was second best to competition like FireWire. The lack of peer to peer was a big problem for me. The confusing connectors are such a problem that it's become a joke that nearly everyone in the world would understand, if there is a place in the world with cell phone coverage then people understand the need to flip a USB connector over 3 or 4 times before being able to plug them in right. Power limitations were also a problem from the start, which lead to many interesting non-standard means to address it. USB 3.1 and the USB-C connector fixed a lot of these problems which basically came down to, IMHO, reinventing FireWire.

    While the USB people are fixing the problems with the past versions with USB 3 I have to wonder if they aren't creating more problems with their over use of the "alt mode" feature. With so many optional alternate modes I believe that there may be a problem with consumers getting confused with the capability of the ports on their device and what kind of cables, devices, and adapters they need to do what they want to do. There are three different video alternate modes for USB-C right now, DisplayPort/Thunderbolt, MHL, and HDMI/DVI. I can just imagine the frustration people could have in trying to find the right cable and/or display to connect to a device with a USB-C port.

    If the USB people are going to make the audio connection capabilities as complicated as the video connection capabilities then they might be making people avoid USB-C because it offers TOO MUCH capability since people won't be sure how to use it. Ports like PS/2, eSATA, VGA, DVI, HDMI, Ethernet, and so on are simple to use and understand because they do one thing, and do them quite well. Trying to stack too much into one port might be great for the computer geek but not so much for a large portion of the public that just want things to work.

    • USB 3.1 and the USB-C connector fixed a lot of these problems which basically came down to, IMHO, reinventing FireWire.

      So in essence, the current spec is Firewire + USB 2.0 bolted together, because it still needs the old set of pins to stay compatible. It's "universal" because when you glue enough different physical standards together, there's a chance that one of them will fit.

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