Analysis of information sources in references of the Wikipedia article "USB" in English language version.
Synchronous sub-mode is not commonly used with audio because both host and peripheral are at the mercy of the USB clock.
Synchronous USB DAC is the lowest quality of the three ... Adaptive ... means that there is no continuous, accurate master clock in the DAC, which causes jitter in the audio stream. ... Asynchronous – this is the most complex to implement but it is a huge improvement on the other types.
Class 2 support enables much higher sample rates such as PCM 24 bit / 384 kHz and DSD (DoP) up through DSD256.
Early USB replay interfaces used synchronous mode but acquired a reputation for poor quality of the recovered clock (and resultant poor replay quality). This was primarily due to deficiencies of clocking implementation rather than inherent shortcomings of the approach.
In applications where streaming latency is important, UAC2 offers up to an 8x reduction over UAC1. ... Each clocking method has pros and cons and best-fit applications.
Some manufacturers may lead you to believe that Asynchronous USB transfers are superior to Adaptive USB transfers and that therefore you must believe in the asynchronous solution. This no more true than saying that you "must" hold the fork in your left hand. In fact, if you know what you are doing, you will feed yourself with either hand. The issue is really about good engineering practices.
ADC-2 refers to the USB Device Class Definition for Audio Devices, Release 2.0.
All operating systems (Win, OSX, and Linux) support USB Audio Class 1 natively. This means you don't need to install drivers, it is plug&play.
The fact that there is no clock line within the USB cable leads to a thinner cable, which is an advantage. But, no matter how good the crystal oscillators are at the send and receive ends, there will always be some difference between the two...
Synchronous is not used in a quality DAC as it is very jittery. ... asynchronous is the better of these modes.
The PCM2906C employs SpAct architecture, TI's unique system that recovers the audio clock from USB packet data.
In applications where streaming latency is important, UAC2 offers up to an 8x reduction over UAC1. ... Each clocking method has pros and cons and best-fit applications.
ADC-2 refers to the USB Device Class Definition for Audio Devices, Release 2.0.
All operating systems (Win, OSX, and Linux) support USB Audio Class 1 natively. This means you don't need to install drivers, it is plug&play.
Class 2 support enables much higher sample rates such as PCM 24 bit / 384 kHz and DSD (DoP) up through DSD256.
We now have native support for USB Audio 2.0 devices with an inbox class driver! This is an early version of the driver that does not have all features enabled
The PCM2906C employs SpAct architecture, TI's unique system that recovers the audio clock from USB packet data.
Early USB replay interfaces used synchronous mode but acquired a reputation for poor quality of the recovered clock (and resultant poor replay quality). This was primarily due to deficiencies of clocking implementation rather than inherent shortcomings of the approach.
The fact that there is no clock line within the USB cable leads to a thinner cable, which is an advantage. But, no matter how good the crystal oscillators are at the send and receive ends, there will always be some difference between the two...
Synchronous USB DAC is the lowest quality of the three ... Adaptive ... means that there is no continuous, accurate master clock in the DAC, which causes jitter in the audio stream. ... Asynchronous – this is the most complex to implement but it is a huge improvement on the other types.
Synchronous is not used in a quality DAC as it is very jittery. ... asynchronous is the better of these modes.
Some manufacturers may lead you to believe that Asynchronous USB transfers are superior to Adaptive USB transfers and that therefore you must believe in the asynchronous solution. This no more true than saying that you "must" hold the fork in your left hand. In fact, if you know what you are doing, you will feed yourself with either hand. The issue is really about good engineering practices.
We now have native support for USB Audio 2.0 devices with an inbox class driver! This is an early version of the driver that does not have all features enabled
Note that Full Speed USB has a much higher intrinsic latency of 2ms
