Device=MIXVIBES U46MK2 ASIO AsioVersion=0 DriverVersion=2
Latency=12 Driver sampling=44100 Nb Input=4 Nb Output=6
Your latency is too high, you must set the sound card buffer to 256 for your first test. (6ms) your setting is actually on 512 (12ms)
You should do or redo step by step the configuration assistant in Mixvibes files->configuration assistant
To get left on channel 1 & right on channel 2 click on the right view on channel 1, it will change to 2