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

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).

Comments

Thin sucks

[PopeRatzo]

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?

Re:Thin sucks

[Anonymous Coward]

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!

Re:Thin sucks

[anegg]

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.

Apple says

[JustAnotherOldGuy]

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

SBU is not what you think it is.

[JustNiz]

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

"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.

Re:Developers of the standard hope....

[jenningsthecat]

"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. ;-)

List of formats that the specifications allow

[NotInHere]

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