I did not attempt to get audio fromt he usb, because in my car installation I wanted the sole N7 usb port to accept 12V/2.1 amps so I don't have to recharge in the house.
I took audio out from the headphone stereo 3.5mm female port, into the AUX in of my Becker 220 CDR factory stereo. Initially, I considered this less than ideal, but I have come to really like this solution.
- I control N7 audio with the physical know on the Becker, which is natural and convenient
- I can switch from the N7 source to the internal Becker FM tuner w/ 1 button
- The Becker sends the N7 audio to the amp in the front trunk without my having to dick around with wiring.
I will be curious to see if you can get usb to work for audio out, especially if you can also accommodate usb charging at the same time.