There is dominant axis on the machine core of the recorder (it is an organic whole with flying wheel) , if use inadvertent, touch dominant axis the turn, will produce the trill that eliminates hard.

• 录音机的机芯上有一根加工精度非常高的主导轴（与惯性轮为一体），假如使用不慎，将主导轴碰弯，将会产生难以消除的颤音。