Thanks for your answer.
I want to work with USB, getting 2 stereos from my computer.
With an analog circuit, i mix the 2 stereos and the result goes, in my computer via the same µc ? (i use a dj sofware who detects 2 stereos output and one input stereo and the software, from my computer, works in 44.1khz.
I think the most difficult is passing a long time on µc datasheet. I have to known the USB protocol.
I am studying "USB Complete The Developer's Guide 4th Ed" book.
If i can find an exemple that brings a 44.1khz stereo from computer via USB it is good. From Teensy, Arduino nano every, STM32F4xxx it is good. No matter if i take 3 parts of theses system. It is clear that a system which pull 2 stereo and push one in the same time it is more professional why not.
I hope i have brought more clarification.
Thanks