It may not be flashy, but the information at Vincent Kar's The Well-Tempered Computer should be costing Google money due to lost searches. Start with Vincent's site, and you only need Google to verify the information that Vincent has already assembled for you. For example, I often hear complaints that USB can't handle high resolution (better than CD) audio due to bandwidth limitations. This is largely bunk, and Vincent concisely clears this up as well as providing useful information related to the topic:
Resolution
A lot of people think USB audio is limited to 16 bits / 48 kHz max.
A lot of (cheap and sometimes not so cheap) USB DACs are indeed limited to this resolution.This is because the manufacturer decided to use a simple and cheap of[f] the shelf hardware solution.
Another common misunderstanding is the specification of the bus (USB 1,2 or 3) and the USB audio standard (1 or 2).
USB Audio Class 1 standard (1998)
This standard allows for 24 bits / 96 kHz max. [that is potentially more than twice the resolution of CD audio]
The standard itself doesn't impose any limitation on sample rate.
Class 1 is tied to USB 1 Full Speed = 12 MHzEvery millisecond a package is send.
Maximum package size is 1024 bytes.2 channel * 24 bit * 96000 Hz sample rate= 4608000 bits/s or 576 Byte/ms
This fits in the 1024 byte limit.
Any higher sample rate e.g. 172 kHz needs 1056 bytes so in excess of the maximum package size.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.
All support 2 channel audio with 24 bit words and 96 kHz sample rateUSB Audio Class 2 standard (2009)
It is downwards compatible with class 1.
USB Audio Class 2 additionally supports 24 and 32 bit and all common sample rates.
Class 2 uses High Speed (480 MHz). This requires USB 2 or 3.
As the data rate of High Speed is 40 X Full speed, recording a 60 channel using 24 bits at 96 kHz (132 Mbit/s) is not a problem.Drivers
From mid-2010 on USB audio class 2 drivers are available in OSX 10.6.4 and Linux.
Both support sample rates up to 384 kHz.
It is unclear if Microsoft is going to support USB Audio 2.
You need a third party USB class 2 driver on Windows.
Vincent also does a more than adequate job of covering USB digital-to-analog converters (USB DACs). However, between the above quoted text and this last link, he stops just short of saying what should now be obvious: there is nothing special about USB DACs. There are only a few manufacturers of audio DACs; and, since the vast majority of these chips are sold for use in stereo and AV receivers and pre-amps, it should surprise no one that the same chips are used in USB DACs. In order for the USB DAC to do its thing, the music player on your PC or Mac is converting audio files (MP3, AAC, FLAC, etc.) into the exact same digital audio data streams that come out of the digital connectors on the backs of CD, DVD or Blu-ray players.