USB Type-C has a number of chances to become the standard for data and charging connector for smartphones and tablets running either Android or Windows. However, in the long-term future, Intel wants USB-C to be even more universal (and therefore pervasive) than it is going to be, which is why at IDF Shenzhen part of one of the talks evolved around using Type-C for audio.

Audio receptacles on PCs and mobile equipment are virtually the last remaining analog interfaces of modern devices, requiring certain techniques to maintain a high audio quality and remove interference. Intel proposes to replace things like 3.5 mm mini-jack with USB Type-C which will help to add features to headsets and will simplify connections of multi-channel audio equipment to various gadgets. This is not the first time a company has proposed to replace analog audio on PCs and mobile devices, but so far, nobody has succeeded due to the ubiquity of 3.5mm. Since the industry may still not be ready to go all-digital, there seems to be a backup plan.

Various types of audio jacks to connect headphones to audio equipment have been around for decades. For example, the original 6.35 mm connector, which is still widely used by audio equipment, was invented in 1878. Meanwhile, two-conductor miniature 3.5 mm audio connector (which is the most widely used audio connector at present) has been around since 1960s. Headphone jacks have evolved; they have gained contacts to support microphones and even basic programmable capabilities to enable remote controls. However, fundamentally, the ability to listen to audio through a speaker has remained the same for over a hundred years: completely analog and barely any smart functionality. Today's smartphones are used for all sorts of different purposes and are connected to a variety of devices, which requires sophisticated interconnection technologies with high data-rates. At the same time, as phones and devices get thinner, or even to simplify some of the internal design, it gets harder to install multiple ports for various purposes. If there were to be a universal connector that does it all, including audio, Intel and some other players want USB Type-C to be that universal connector.

In fact, USB-C can be used to transfer analog audio in accordance with the specification of the connector. It all comes down as to how that audio is transmitted.

The USB-C has sideband use pins (SBU1 and SBU2) which can be used for analog audio in audio adapter accessory mode. Use of the sideband pins should not impact data transfers and other vital functionality of USB-C cables, which should make them relatively simple from the engineering point of view. In this case, the USB-C connector will just replace the 3.5 mm mini jack and may even gain some additional features, such as a thermal sensor in an earpiece could measure temperature for fitness tracking.

The concept is not completely new and we saw it years ago - back in the 2000s, Motorola used the mini-USB connector on its feature phones to enable charging, data transfers and a headset connection. The idea to use one connector for everything was not entirely bad, however, it left users without a choice of headsets. However, if the makers of devices (as well as producers of audio listening equipment) adopt USB-C, the is potential that the problem will not occur again. In the advent of digital signal transfer, this allows the headset to drive the digital-to-analog conversion, removing electronic interference from the host and potentially offering a wide array of audio results.

However, transferring analog audio using USB-C’s SBU pins is not the only thing that Intel is working on.

At present, Intel is finalizing the USB Type-C Digital Audio technology and plans to release its specification later in Q2. The company does not reveal a lot about the standard right now, but notes that it is working on updating the USB Audio Device Class 2.0 specifications to support new connector, expand the list of recent audio specifications and features, improve power management and simplify the discovery and configuration model to make the upcoming headsets as easy to use as today’s headsets.

In fact, one of the important issues with streaming audio over USB is the synchronization of data streams from the host to the receiver. The USB Audio Device Class specification solved the problem in the past and because Intel mentioned the USB Audio Device Class 2.0 in its presentation at IDF, this may mean that the new the USB-C Digital Audio spec will rely on this synchronization mechanism as well. Intel wants its USB-S Digital Audio to be backward-compatible with USB Audio (1.0 and 2.0), but naturally plans to add support for new music formats.

Usage of digital audio means that headsets should gain their own amplifiers, DACs and various other logic, which is currently located inside smartphones. Intel proposes to install special multi-function processing units (MPUs), which will perform beam forming, noise suppression, acoustic echo suppression (AES), acoustic echo cancellation (AEC), non-linear processing and other operations. The MPUs will also support HDCP technology, hence, it will not be possible to make digital copies of records using USB-C digital headset outputs. It is unlikely that audio processing will be offloaded to external headsets completely, but the latter will clearly gain their own chips. This may, however, see a spike in cost, especially at the super-low end.

A good thing about USB Type-C headsets with MPUs is that they are going to be software upgradeable and could gain functionality over their lifespan. Intel admits that such MPUs will make digital headsets more expensive compared to analog devices, but high volumes and new process technologies will help to reduce the cost of digital headsets over time. In fact, USB Audio headsets and audio chips for them are not something completely new. For example, Plantronics Audio 655 DSP headset costs $49.99, whereas CMedia’s HS-100 chip for headsets is available $1. Therefore, from the cost perspective, digital headphones should not be too much more expensive in general. Meanwhile, Intel wants USB-C digital audio headsets to offer “significant value at higher end” and have improved functionality in a bid to become popular among consumers.

The industry has successfully replaced analog cables with HDMI for video equipment in the living room and in the coming years will retire the D-Sub interconnection for computer displays. However, audio jacks have survived multiple generations as other standards have changed. In fact, Intel itself eliminated analog audio jacks in its first-generation NUCs PCs, but had to return them in subsequent generations. With USB-C Digital Audio Intel may not be alone. Google’s Android 5.0 already supports USB DAC devices and thus digital headsets. Moreover, last week LeEco released several smartphones without audio jacks, so, there are attempts to eliminate them from mobile devices already. One maker will not make any difference, but a coordinated move by market leaders, such as Samsung, LG or HTC, could have a significant impact.

Source: Intel

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  • taisserroots - Saturday, April 30, 2016 - link

    DACs are bulky, you can't put a DAC on earphone cables, it's heavier than the earphones themselves, no more morning jogs without your earphones falling out
  • jlabelle - Thursday, April 28, 2016 - link

    - How about doing an article addressing these issues guys? -

    with this : "In fact, USB-C can be used to transfer analog audio in accordance with the specification of the connector. It all comes down as to how that audio is transmitted."
  • taisserroots - Saturday, April 30, 2016 - link

    It's a standard, which would then require a cheap adapter.
    still means you cannot use while charging, still means you are pushed to buy new headphones.
    Again it means there are no benefits only downsides if that is the case.
    It also means only one port can be for audio.
  • kpb321 - Tuesday, April 26, 2016 - link

    USB-C is really turning into a mess. This is yet another thing that may or may not work on any given port. I understand the appeal of the single cable docking station for a laptop with the cable providing power to the laptop and video/usb/data to the docking station and the use for alt modes but the whole thing is a mess. No amount of logo's is going to solve the issue and your average people are going to just be stuck plugging something in and hoping it works and when it doesn't probably not knowing why.
  • zhenya00 - Tuesday, April 26, 2016 - link

    Completely agreed. I don't see how everyone has missed this point in the rush to 'standardize' on one physical connector. While there are benefits to that road, at least the current way you can be pretty confident that if the cable fits the port, it's going to work. We've already seen this in practice in the few usb-c devices we have now. A new Dell Precision laptop with Thunderbolt that doesn't support charging, and Thunderbolt docks that don't work when plugged in to the retina MacBook.
  • ddriver - Thursday, April 28, 2016 - link

    Well, making a reversible connector was a clear indication the level of retardation in the general population is scheduled for an increase. We aren't talking convenience here, we are talking "retard proof", or "retard friendly". And it is way more expressive - it is a win win for the industry and just yet another in a long series of lose lose for the consumer.
  • chaos215bar2 - Tuesday, April 26, 2016 - link

    Really, HDCP? Because _anyone_ pirates music by recording the stream off of a USB audio device.

    On the up side, now I can get a blast of 32 bit, 384 kHz static in my ears to match the 4k, HDR snow on my TV when the HDCP handshake fails.
  • Shadowmaster625 - Tuesday, April 26, 2016 - link

    3.5mm jack is a lot more robust than any type of USB, and yet headphones still go flaky all the time. At least with analog when it goes flaky you know what is happening. With digital it is just going to not work at all and you are not going to have the slightest clue why. So you're going to end up spending even more money replacing even more pricey equipment. Nope, not gonna happen to me.
  • taisserroots - Saturday, April 30, 2016 - link

    You cna even connect those to an amp with a quater inch adapter, which is even more durable, emaning you cna use your headphones in more places
  • name99 - Tuesday, April 26, 2016 - link

    "A good thing about USB Type-C headsets with MPUs is that they are going to be software upgradeable and could gain functionality over their lifespan"

    Oh Intel, still clueless after so many years. How EXACTLY do you expect this to play out? In particular, what is the mechanism by which the software update gets from its initial location (on some server somewhere) into the ROM of the headset?
    Because the way this has ALWAYS worked in the past is that you were supposed to run some random.exe (yeah, that sounds like a good idea idea --- I just trust some random .exe I find on a web site that looks like it was designed in 1998, presumably with security practices to match) on my Windows PC, while the headset is plugged into the PC. This mechanism left Mac users screwed, but that was considered acceptable because, tough.

    But it's a new world these days. If your game plan is that you expect everyone to own a Windows PC, good luck with. And if your game plan admits to reality, then what? You expect every hardware vendor to write an Android app and an iOS app as the updater? And what about that (not quite negligible) fraction of the population that still have only PCs and Macs? What's going to happen when Microsoft complains that there isn't a Win Phone updater? What about those people who bought their headset to plug into their TV and could not care less about the world of phones and PCs?

    The arrogance, ignorance, and sheer idiocy behind this bland sentence is truly remarkable...

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