Is there a knob for ground balancing? The md's I've had that had one followed this process. You turned the md to all metal mode, held the coil up in the air and noted the loudness of the threshhold sound. Then you lowered it to the ground and noted whether the loudness went up or down. The goal was to have it stay the same as up in the air. So, if the threshhold got softer as you went to the ground, you turned the knob one way, if it got louder, you turned the knob the other way. You keep raising and lowering it and turning the ground balance knob until the threshhold sound stays the same whether up in the air or on the ground.