I used a Shure M58 another Shure with on and off switch ( can't think of the model #) and also tried my Shure headset wirless mic with the same results. It seems that there is also distortion while talking or singing without the vocalist on. I'm taking the keyboard back Monday to get another( I hope ). Bob P.S. Also tried a Audex mic with the same results. Also did a factory reset, which did nothin to help. # 3 also, tried tthe settings from Micheal with no luck.