DDJ 800 Microphone problem

Hi All!

DDJ 800, and the latest rekordbox.  Older versions had the same error. Whatever microphone I plug into the XLR , the mixer produces very, very poor quality. SM58, Sennheiser, etc. No dynamics, no normal timbre. Cable and microphone perfect, Tested on another device. What could be the problem?  Is the microphone channel so weak?