Can not see white line
Check volume level of your microphone. It should be in the yellow zone during singing. Turn up microphone volume. If it does not help, try enable “Microphone +20db Boost” on the Windows controls panel.
Also the level of side noises should be low. If you sing with mp3 try to turn down the Mp3 background volume. Or listen it through headset.
If volume level is ok, but voice line still not visible, check “Auto Select Range” option.