sorry I can't type in Thai now
YOU CAN DO IT KRAB.
1. Set recording Source to Main Mix or Stereo Mix
2. In sonar, Create new Audio Track (STEREO)
and Select input to ASIO Stereo In
3. Click (R) Icon (record arm) , you will see a Red R Icon
::: and Don't Click Direct monitor (ECHO) icon !!!
4. Click option->project and "uncheck all metronome sound"
if you don't do this, you will hear the metronome while recording and it will be recorded too
5. Start Record and then play your karaoke
AND YOU CAN USE THIS TRICK FOR ALL SOUNDCARD (ONBOARD+ASIO4ALL TOO)