Is it possible to send audio data to the Teensy3.6's USB-Host port, to connect it with a USB-Audio Interface?
There are a lot of USB audio interfaces, expensive combinations like a ZOOM R24 -audio recorder/mixer, the Yamaha THR10 guitar practising amp,
, or cheap devices like
Behringer U-phoria UM2
Using something like this with the teensy would add a very good Audio I/O to the teensy 3.6 without using the audio shield.

The nice audio library seems to cover the first (Micro-USB) port only, not the soldered USB-OTG connector and is intended for audio exchange to and from a PC, not form or to a device.
Or have I missed some information?