iPhone usb audio

Hi, I plugged my iPhone into the QC using USB camera connection kit to try and play a backing track to jam along to. The sound was quiet and warbled no matter what input/output combinations I used. Has anyone had success with iPhone usb audio or is it best to use iPhone headphones audio out into input 2 or return jack in QC?

I couldn’t get my iPads to connect (using the specified usb to lightning/C camera adaptor) so I ended up using a basic 2 channel audio interface (Roland Rubix 24): I connect the QC cable output to its input and use the usb output of the Rubix. That works fine.
An expensive workaround though !

Sadly, the usb 1 & 2 outputs are dry. Wet on 3&4. Only usb 1&2 can be defaulted on apps without audio input selection.