MHC-V42D Bad noise at 200Hz, especially on microphone

[manov_v]

Try with different microphone its the same result, my wife voice don't have a problem. I gave the system to a Sony service and they answer that this problem is very insignificant. But for me is very big because I can't use properly karaoke function. What can I do? 

[Joe_Dohn]

Have you tried using the other Mic port or adjusting the Mic level as mentioned in the Help Guide?