Understanding USB-C Audio Accessory Mode Limitations

[Elclark.]

I'm trying to get a better grasp on the technicalities of USB-C audio, and I'm still confused about how it works (or doesn't) with various devices. Here are some questions I haven't been able to find clear answers on:

1. I often see "Audio Accessory Mode" and "audio passthrough" used interchangeably. Are they the same thing? If not, what's the correct way to understand and use these terms?
2. Why don't product descriptions for basic USB-C to 3.5mm adapters (without DACs) ever mention Audio Accessory Mode or audio passthrough capabilities?
3. Do phone makers like Xiaomi and OnePlus utilize standard USB-C Audio Accessory Mode in their USB-C to 3.5mm adapters, or have they developed their own proprietary audio output solutions?
4. Android documentation seems to suggest a 16-bit/44.1kHz limitation for Audio Accessory Mode. However, apps like Poweramp show my output is 32-bit/48kHz over USB-C. Why?
5. I've heard that Audio Accessory Mode is being deprecated from the USB standard. Is this true, and if so, what are the implications for USB-C audio moving forward?

[andrewilley]

I can't answer everything there, but Audio Accessory Mode simply means that the USB-C port (and the device plugged into it) is able to process analogue audio via pins on the USB-C connector, so the dongle or headset does not need to contain its own DAC. Basically it's like having a 3.5mm socket for audio generated by the phone, but the analogue L & R audio is routed via the USB-C connector instead. Not many devices support this as far as I know. 

Andre 

[ajay-0911]

@andrewilley powamp的优势：

1.视觉动效

2.丰富的EQ调音

3.简单的操作逻辑

植入USB-DAC的独占控制功能会更好

这意味着它会变成一款真正的

high-fidelity播放器

 

[Translation]

Advantages of Poweramp:

1. Visual animation
2. Rich EQ tuning
3.Simple operation logic

Exclusive control of USB-DAC would be better. This means it will become a real high-fidelity player

Edited June 19 by andrewilley
Added Translation