Most of the time (not always) problems with mic settings, particularly when singing with MIDI files, the problem is twofold. More often than not the MIDI file volume is abnormally high. Consequently, the person singing cranks up the input volume of the keyboard's vocal processor until it distorts.

It really is not the keyboard's fault that distortion occurs. You would have the same distortion problem with any sound system that is overdriven. The problem can readily be solved by downloading Michael Bedesem's MIDI Player II program, which will adjust the MIDI file's volume level to normal levels, thus allowing you to set the keyboard's mic volume to normal levels. You will find Michael's program at http://www.psrtutorial.com/MB/midiplayer.html It's a great program, and I forgot to mention it is free.

Good Luck,

Gary