Distortion that you describe generally happens at the input stage. Either the DJ mic is distorted as it passes throught the mic prein his board or at the input stage of your camera. You can’t do much about his board signal(If it’s crappy getting to you, nothing you can do will clean that up.)
Check the sensitivity setting on the transmitter and adjust until distortion is eliminated. OR You can “pad down” the signal before it gets to you (shure makes an in-line pad) and put this between his board and your X-mitter.
