Audio Over USB-C Specification Published (Analog and Digital Possible)

[Master Disaster]

You know what would solve all this mess? A Bluetooth to 3.5mm adapter. 

[Dackzy]

Sorry, but this is just stupid. USB C is all over the place and what is so wrong with the 3.5mm jack that they need to use USB C now, it just seems like they are just doing it because iPhone 7 removed the jack, so they want to do the same, but come on, 3.5mm has been with us for ages and it is such a huge marked. 

 

Good luck trying to kill 3.5mm, that is not going to happen anytime soon. 

 

I also feel like USB C would be a pain in the ass for headphones.

 

[Rune]

4 hours ago, Master Disaster said:

You know what would solve all this mess? A Bluetooth to 3.5mm adapter. 

We have those. They are called bluetooth receivers and 99% of them are garbage.

[Katsunaka]

Please just let them be. 

 

Dont chase Apple. I prefer being able to charge my phone and play music over aux in my car. 

 

I guess they didnt see the backlash apple caught over the same thing. 

 

I refuse to buy an adapter that lets me do something my phone can already do. 

 

Dont do it Android phone makers.

[Guest]

FFS how about we improve on the analog 3.5mm standard instead of combining everything into one port?

[Fetzie]

7 hours ago, Master Disaster said:

You know what would solve all this mess? A Bluetooth to 3.5mm adapter. 

How do you propose sending electricity via bluetooth to the headphones?

[SpaceNugget]

12 minutes ago, Fetzie said:

How do you propose sending electricity via bluetooth to the headphones?

uh, a battery?

[Fetzie]

57 minutes ago, WaxyMaxy said:

uh, a battery?

if I'm going to have to hang a brick from my ear, I'd rather stick with the 3.5mm jack

[Sniperfox47]

I just got through reading the USB Audio Class 3.0 and just want to clarify a few things Anandtech (and most of the other news reports which it seems to have copy pasted from) got wrong:

 

Analog audio has absolutely nothing to do with it. USB type C has had support for analog audio over the side bus pins since it came out. It was a part of the USB type-c standard (audio accessory mode). The USB Audio Class 3 does not make a single comment on analog audio in the entire spec. The "Formats" document mentions "side-bus" in the spec, but it's referring to vendor specific audio formats, not the side-bus pins. USB Audio Class 3 is purely for digital audio.

 

Likewise, USB type-C is almost completely unrelated and it will work equally well over type-A plugs. The USB Audio Class 3 documents make no reference to Type C, not even linking to it's documents. To my untrained eye, the new power saving and discovery features seem to help type-C devices far more than type A devices, but they're not exclusive.

 

UAC3 seems to be more set on modernizing USB Audio than defining anything specific to USB type-C. Some examples of what new stuff it supports:

Newer formats, better support for Superspeed mode, power saving features for mobile devices, rich features like noise cancelling and beam forming, hotword detection, and easier detection of various audio inputs and outputs.

It does this via:

Redefining various format descriptions, optimizing device and function descriptors, mandating support for low power mode and supporting power domains (zones) so functions such as noise cancelling or a microphone can be turned off independent from say your headphones, adding a new logical unit called a Multifunction Processor which can represent virtually any algorithm or set of algorithms natively, and mandating support for the new audio device discovery protocol (optional on UAC2).

 

It also looks like there were some changes to the stuff related to the various clocking methods (isochronous, adaptive, and asynchronous) but I'm not completely sure what's changed so maybe someone else can spot it.

 

It's a big change that's really positive for digital audio over USB Type-C. It makes it easier for developers to implement their devices and better for users who want rich features and lower power use devices, but it's independent from the analog audio support USB Type C already had, and also has benefits for USB Type A devices.

[abazigal]

9 hours ago, LAwLz said:

The title is correct. This specification was specifically designed for USB Type-C, and will in fact only work over Type-C because it uses the SBU pins for the analog audio. Those pins only exist in the Type-C connector.

 

 

 

It would not necessarily increase the price of USB type-C ports, because these things are optional. That's why it is so messy though. There are a ton of different things which can run over USB type-C, such as HDMI, DP, analog audio and so on, but manufacturers are free to implement whichever parts they want. What this means is that not all USB type-C ports are created equally.

So on one phone the USB type-C connector might be able to plug into your TV and send HDMI over it, but another phone with USB type-C might not be able to do the same.

Thanks for the clarification. 

 

So if I get you right, the USB-C name only refers to the shape of the connector, but not necessarily what functionality that functionality might come with? So one USB-C port might come with thunderbolt 3 speeds, while another could be limited to USB2.0 speeds? 

 

If so, this is a mess. If USB-C is indeed being touted as the one port to rule them all, then someone really needs to take charge and start enforcing this kind of standard. 

[LAwLz]

6 hours ago, Sniperfox47 said:

-snip-

I'll go over the documents later too to see if Anandtech and Co got it wrong. I really hope they didn't. 

 

 

5 hours ago, abazigal said:

Thanks for the clarification. 

 

So if I get you right, the USB-C name only refers to the shape of the connector, but not necessarily what functionality that functionality might come with? So one USB-C port might come with thunderbolt 3 speeds, while another could be limited to USB2.0 speeds? 

 

If so, this is a mess. If USB-C is indeed being touted as the one port to rule them all, then someone really needs to take charge and start enforcing this kind of standard. 

Yes that's exactly right. It's not just speed differences either. One Type-C port might be able to send HDMI over it, while another pre might not. So if your TV had a USB Type-C port then one phone might be able to connect to it and show pictures, but another phone might not (because it doesn't support HDMI over Type-C ).

 

One Type-C port might be able to do:

USB 2.0 speeds.

HDMI

Analog and digital audio.

 

Another might be able to do:

USB 3.1 speeds

Display Port but not HDMI.

Ethernet

Digital audio only.

 

 

I think you can see where this might become an issue. So just because you plug one Type-C device into another Type-C device, doesn't mean they will work.

I think they need to do some nine of sticker system or whatever you want to call it. So that all devices with a Type-C port comes with a little chart which clearly shows what it is capable of. Then the average Joe could just compare "does both my devices have the HDMI logo on the fact sheet? Good then they will work together". 

[jaggysnake57]

23 hours ago, Misanthrope said:

1) That's just their stupid design though: Phones used to have 2 or even 3 different ports at one point (headphones, data and power) there's no reason why they can't make a dual USB type C phone, other than Apple and their stupid decisions and Samsung copying every fucking thing they do.

 

2) Existing USB type C interfaces are fucked yes, but I'd argue that they're really not that many so fuck em. Early adopter's tax I'd call it.

yeah like having 2 or 3 ports on a phone isnt a stupid idea.

18 hours ago, Misanthrope said:

Is Apple willing to license it out to others?

if they can make money off it yes they will

13 hours ago, Dackzy said:

Sorry, but this is just stupid. USB C is all over the place and what is so wrong with the 3.5mm jack that they need to use USB C now, it just seems like they are just doing it because iPhone 7 removed the jack, so they want to do the same, but come on, 3.5mm has been with us for ages and it is such a huge marked. 

 

Good luck trying to kill 3.5mm, that is not going to happen anytime soon. 

 

I also feel like USB C would be a pain in the ass for headphones.

 

its called progression, deal with it. and if phones stop shipping with 3.5......its dead.

[Misanthrope]

31 minutes ago, jaggysnake57 said:

yeah like having 2 or 3 ports on a phone isnt a stupid idea.

It isn't. It has worked just fine for everybody for years, decades even at this point. The stupid idea is thinking we can do ok with just 1 port when we clearly don't have widespread and cheap wireless accessories yet.

[jaggysnake57]

Just now, Misanthrope said:

It isn't. It has worked just fine for everybody for years, decades even at this point. The stupid idea is thinking we can do ok with just 1 port when we clearly don't have widespread and cheap wireless accessories yet.

1 multiple ports of the same type is stupid.

2 you think companies wont start working on cheap BT earphones now?

 

[Misanthrope]

Just now, jaggysnake57 said:

1 multiple ports of the same type is stupid.

2 you think companies wont start working on cheap BT earphones now?

 

1) Again I fail to see an argument here just a presuppositional assertion: look at the back of your fucking PC, do you only have 1 USB port? The whole point of USB is that it replaces lots of different functionality, obviously you need several of the same port because you still need several different functionalities.

2) Cheap BT earphones are already available. They're just not widespread enough because they're not without drawbacks: battery life still sucks. So it's not just "get BT earphones" but more like "Get BT earphones that can last at least a week on a single charge" before we can say "Ok this works" as we had said with wireless mice and keyboards for example.

[jaggysnake57]

2 minutes ago, Misanthrope said:

1) Again I fail to see an argument here just a presuppositional assertion: look at the back of your fucking PC, do you only have 1 USB port? The whole point of USB is that it replaces lots of different functionality, obviously you need several of the same port because you still need several different functionalities.

2) Cheap BT earphones are already available. They're just not widespread enough because they're not without drawbacks: battery life still sucks. So it's not just "get BT earphones" but more like "Get BT earphones that can last at least a week on a single charge" before we can say "Ok this works" as we had said with wireless mice and keyboards for example.

1 do i stick my fucking pc in my pocket? is it 7x3 fucking inches and 7 mm thick? the use cases of charging and listening to music are small in a mobile device. not to mention charging and listening to music are remedied with either a cheep adaptor of a wireless charging pad.

2 with greater demand comes more investments and in turn improvements. 

3 1 week battery life, da fuq you on about. yo need 2 days at best why are people so obsessed with not chagrin something at the end of the day.

 

your trying to make a mountain out of a mole hill

[Misanthrope]

2 minutes ago, jaggysnake57 said:

1 do i stick my fucking pc in my pocket? is it 7x3 fucking inches and 7 mm thick? the use cases of charging and listening to music are small in a mobile device. not to mention charging and listening to music are remedied with either a cheep adaptor of a wireless charging pad.

2 with greater demand comes more investments and in turn improvements. 

3 1 week battery life, da fuq you on about. yo need 2 days at best why are people so obsessed with not chagrin something at the end of the day.

 

your trying to make a mountain out of a mole hill

You stick your phone in your pocket which already has probably 2 ports: micro usb and 3.5 inch jack. There's literally no difference to one with dual USB 3 type c ports. There's nothing stupid about it, there's nothing wrong about it, sorry to say it's mostly just you and I just disagree with you so I consider this matter exhausted.

[Sniperfox47]

3 hours ago, LAwLz said:

I'll go over the documents later too to see if Anandtech and Co got it wrong. I really hope they didn't. 

They did. But I'm pretty sure it was a combination of combining various other news articles that had wrong info, and looking at the short list of differences between UAC2 and UAC3 and making assumptions.

 

For example the list of changes says "New Multifunction Processing Unit", but if you look at the description of a Multifunction Processing Unit in Audio Characteristics>Audio Function Topography>Processing Unit>Multifunction Processing Unit on page 40 it specifically states that it's not necessarily a physical piece of hardware, and is instead a logical topology descriptor used to describe DSPs in the topology that do one or more of:

•Algorithm Undefined (generic algorithm •descriptor)

•Beam Forming Algorithm

•Acoustic Echo Cancellation Algorithm

•Noise Cancelling Algorithm

•Blind Source Separation Algorithm

•Noise Suppression/Reduction

 

This allows something like Creative's X7 to expose all of it's little functions to be described over the USB audio class so generic software can offer controls for them, rather than requiring Creative to write a whole driver to handle that.

 

That's cool, but what it does not do is act as a physical generic processor that handles all the UAC3 stuff.

 

Don't get me wrong, I hope there are DAC/AMP/DSP chips being produced with the features listed above, that will support both UAC3 (digital) and Headset Adapter Accessory Mode (analog). I'm just saying that's not what the spec is describing.

 

Edit: Also to be clear, there's nothing particularly special about audio over type-C. Using the analog mode you've essentially got a TRS connector. It's electrically compatible. And using USB Audio Class 1/2 works the same as with any other usb device, just it tends to be pretty power hungry, especially if the chipset has lots of features. I have a pair of UAC2 headphones that I use with my phone currently and they work great.

Edited October 2, 2016 by Sniperfox47

[jaggysnake57]

3 minutes ago, Misanthrope said:

You stick your phone in your pocket which already has probably 2 ports: micro usb and 3.5 inch jack. There's literally no difference to one with dual USB 3 type c ports. There's nothing stupid about it, there's nothing wrong about it, sorry to say it's mostly just you and I just disagree with you so I consider this matter exhausted.

more ports more ways for water and dust to get in, 1 more thing to go wrong, less room inside the device, looks stupid.

 

are we going to have 1 port for data and 1 for power or both doing both.... 

 

its stupid

[Sniperfox47]

19 minutes ago, jaggysnake57 said:

more ports more ways for water and dust to get in, 1 more thing to go wrong, less room inside the device, looks stupid.

 

are we going to have 1 port for data and 1 for power or both doing both.... 

 

its stupid

Two ports for both. Or you can just do what I do and carry around a tiny Power Delivery compliant dock and split your one port into Power, Headphones, Game controller, and anything else you need.

 

It needs to be power delivery compliant not to charge your phone faster (since most cap at 5v3A anyways) but rather to tell your phone "Hey! I can provide charge even though I'm a downstream device." The Kensington and Startech Type-C hubs are nice for splitting your ports, but you can't use them for charging and data at the same time.

[tsk]

No one is going to make phone with two USB ports. 

A lot of people seems to be screaming "apples fault!", while it's really Intel who is pushing for this. Anyway the 3.5mm jack is going to die, like it or not. 

[Dackzy]

2 hours ago, jaggysnake57 said:

its called progression, deal with it. and if phones stop shipping with 3.5......its dead.

There is nothing better with USB C, the marked for 3.5mm is insanely huge

[Sniperfox47]

16 minutes ago, tsk said:

No one is going to make phone with two USB ports. 

A lot of people seems to be screaming "apples fault!", while it's really Intel who is pushing for this. Anyway the 3.5mm jack is going to die, like it or not. 

I don't know. I could definitely see some larger niche phones having more than one USB port. Or at least tablets. The primary reason they didn't in the past was that they were forbidden from having more than one port if they supported USB OTG (though some companies like Minix conveniently forgot that part of the spec anyways). With USB-C dual function devices that concern is gone.

 

I don't see it becoming a standard thing, but I could definitely see it on some of the more niche devices, like gaming or audiophile phones/tablets.

 

A dual USB Type C jack device would take up only a tiny bit more floor space than the equivalent headphone jack, and still be thinner inside the phone, and less prone to water leakage. Plus it would support other data over the same port.

 

At the very least we'll see Audio Adapter Accessory Mode (analog) adapters that have a charge port on them come out for devices like the Moto Z, since that's specifically addressed in the original USB Type-C Spec and seems like a silly ommission on Lenovo's part.

 

[jaggysnake57]

1 minute ago, Dackzy said:

There is nothing better with USB C, the marked for 3.5mm is insanely huge

its digital that in its self is an improvement

 

[Dackzy]

1 minute ago, jaggysnake57 said:

its digital that in its self is an improvement

 

The audio signal is not digital. AUDIO IS ANALOG. The whole point of this thread is to say that they put analog into USB C