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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  • stephenbrooks - Tuesday, April 26, 2016 - link

    Intel want to sell you a wireless NIC on your headset too, so you can download patches from your wi-fi :-p
  • 10101010 - Wednesday, April 27, 2016 - link

    In the past decade, Intel started building in spyware and DRM into their processors. For many customers, there is no such thing as security on much of the PC platform due to this. Now with USB-C DRM Audio Intel is expanding their spyware/DRM push to peripherals.

    Considering that every spyware/DRM addition to a platform decreases its overall value to customers. It's no wonder that the PC market is in death spiral and Intel is laying off so many employees.
  • Anato - Wednesday, April 27, 2016 - link

    Most important thing is, who is going to support older headsets. Even now, we have huge problems with older phones as they past 1 or 2 year mark, manufacturer stops software updates. Now I don't see why headsets would be better.

    I hope EU or USA pass laws to bind manufactures to support their product with at least security updates as long as more than 5% of total devices sold is in use. Because when we start connecting those washing machines and fridges to internet (of things) there will be abundance of security holes up to 20 years old machines. Then few coders in cave can bring whole nations electricity grid down simply by commanding starting and stopping these machines in apt order.
  • phoenix_rizzen - Tuesday, April 26, 2016 - link

    Could Android devices finally get their equivalent to the Apple Dock connector? One plug, that allows you to connect to a dock and play audio (analog or digital) and/or video, and charge the device, and transfer data, and and and? Could we, finally, start to see a phone-agnostic accessories market start to develop?

    This could be the start of something wonderful ... if everyone plays ball together!
  • Impulses - Tuesday, April 26, 2016 - link

    This already exists, there's two issues tho. There's several different implementations (from USB audio over 2.0/OTG to MHL & Displayport), and the mass market wants to go full wireless anyway so nothing truly universal will gain traction...
  • phoenix_rizzen - Wednesday, April 27, 2016 - link

    There are lots of alternatives for Android devices, but nothing standard across even multiple phones from a single OEM. And there's nothing as nice and neat and easy-to-connect-to like the Dock Connector.

    Do you use MicroHDMI + MicroUSB + headphone jack?

    Do you use MHL-over-MicroUSB + headphone jack?

    Do you use Slimport + headphone jack?

    Can you pipe digital audio over the USB port? On some phones, yes, on others no.

    Not every phone has the ports in the same location or the same distance apart, so you can't make a universal mount on any devices. Not every phone even has the connectors all on the same side of the phone.

    USB Type-C connector could eliminate all this by allowing power, digital audio, digital video, and data over the same connector, which would be in the middle of the bottom edge of just about every phone. Now 3rd-party accessory makers have a single connector to add to their devices and it will work with any Android device with a USB Type-C port.

    The reason wireless is "taking off" on Android devices is the lack of standardised ports, so they just eliminate the port. It's not a better solution, just a different one, with it's own set of issues.
  • phoenix_rizzen - Wednesday, April 27, 2016 - link

    You can also pipe analog audio over the USB Type-C connector, so it really is an everything-connector, like the Dock Connector or Lightning.
  • taisserroots - Saturday, April 30, 2016 - link

    you can, apple docks have a DAC integrated into them lighting connector devices have DACs integrated into them, which is why they can sell overpriced gimmick hardware.
    You can transfer digital audio over these connections to a DAC via micro USB, phones can use an OTG cable/connection to do so. Older phones which don't have OTG support and only terminal connectors suffer from this.
    The USB-C cable doesn't eliminate any of the problems you've stated, to have a dock which fits and supports every phone, of all sizes, of different weights is impossible, you can only go as far as having a cable which supports all of them.
    which again means this change doesn't bring anything, as every phone has a 3.5mm audio jack already and all you are doing is changing the connection.
    Besides you cannot have power and analogue signal going down the same cable at the same time. The fact that a current produces a magnetic field means you can't have an analogue signal in the same cable
  • benzosaurus - Tuesday, April 26, 2016 - link

    As for switching to digital connections for consumer audio, it's always seemed to me that it's just going to result in one cheap DAC being replaced with a pile of even cheaper DACs which is just going to make everything more expensive and sound worse, for the dubious benefit of the technology being "cooler" or something.
  • onewingedangel - Tuesday, April 26, 2016 - link

    Surely a lossless wireless transmission standard makes more sense for headphones - usb type c just needs to supply the power when the headphone batteries are low. To charge phone/device and headphones at same time you just need two usb type c connectors on a power adapter.

    For a multi-channel bit stream it's just a data transfer anyway, so standard type c should already work.

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