hi guy,i have a question,please help me!

  1. A simple USB device

You need to hit it closer than that. What device?
I think it’s still true Audacity won’t play multi-track. Your choices are mono and stereo.


Plus, without special software/drivers a Windows application can only record from one device at a time and play through one device at a time.

The best solution for multi-channel playback is a 5.1 channel or 7.1 channel soundcard (but not with Audacity).