The human heart **** vibration frequency is about a few hertz, the general speaker dive frequency is not so low, even to a few hertz energy is relatively small. But the human chest structure is more complex, different organs, local thoracic cavity, the Department may become *** sounding cavity, once the local *** vibration will cause a certain burden on the organs, long-term thoracic *** vibration or local *** vibration of the situation will cause discomfort and damage. A more obvious example is inside the nightclub, sub-low frequency speakers emit 40Hz ~ 20Hz energy caused by human chest local *** vibration triggered by not. Such as some people themselves sensitive to sound, the body structure *** vibration frequency is relatively high, it is easy to cause chest discomfort, so try to avoid appearing in the low-frequency energy more occasions, such as nightclubs, performances, KTV, square dance scene. The last thing to say is that the cause of chest discomfort, is the chest cavity of the organs or tissues of the vibration or displacement of the larger, if the heart installed pacemakers and other electronic devices, it is strongly recommended not to long-term exposure to low-frequency high sound pressure level below.