Download of USB-Audio 3.3.0 for Mac was on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The application lies within System Tools, more precisely Device Assistants. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. The actual developer of this Mac application is Ploytec GmbH.
From the developer:
USB Audio is a free app that enables buffersizes down to 32 samples (0.73 ms) and creates an ultra high speed USB audio connection, bypassing the operating system's audio. If you use a USB2 hub the data might be delayed due to necessary buffering on changing the speed.
You may want to check out more software for Mac, such as ToFi, iStar Composer or toDoo, which might be related to USB-Audio.
Drivers