Either the first and foremost (one single sound and then silence) or continous sounds that hears? Let me be clear.. For me at while releasing the knob and while the mercury comes down from say 200, at 140 i hear one light sound. Then silence. At 130 i hear one more light sound. Then silence again. At 120, i start hear continous loud sounds. So which is my systolic reading 140 or 130 or 120 ? Pls Pls help me! Thankful to you.