What sampling frequencies do you see in AHI settings? Unless you can match the frequency of your audio files, distortion is a given (because of AHI).
Frequency is set to 44100 Hz, which works with internal device ("AppleI2S").
What I observed further is: I can hear mousemovents. So when Sound is disturbed moving the mouse kind of helps to fix audio.
But when sound is good, one should not move the mouse or type with keyboard.
Entering text and listening to USB-Audio seems impossible to me.
So currently listening is possible, but turns of any "multitasking" or other use of the computer.
Please tell me where to look at or how to improve the useabilty of USB-Audio.