USB Audio Class
More info
- Owner
- USB Implementers Forum
- Released
- 1998
- Type
- Device class
The standard that lets a USB sound device work with the operating system's own driver — what "class compliant" on the box actually means.
UAC 1.0 arrived in 1998 and was fine for headsets and simple interfaces, but it was tied to USB full speed, which in practice meant a handful of channels at 24-bit/96 kHz. UAC 2.0 from 2006 used USB 2.0 high speed and opened the door to high channel counts and sample rates. Audio moves as isochronous transfers, and in asynchronous mode the device's own clock sets the pace and asks the host for more or less data — keeping jitter down to the interface's crystal rather than the computer.
macOS and Linux have had UAC 2.0 drivers for years. Windows only got one in Windows 10 version 1703 in 2017, which explains why manufacturers kept shipping their own ASIO drivers for over a decade.