The resonant frequency of the human heart is about several hertz. The diving frequency of general speakers is not so low, even at a few hertz, the energy is relatively small. However, the structure of human chest is complex, and different organs, local chest and chest cavity may become resonance cavities. Once local resonance occurs, it will cause a certain burden to organs, and long-term chest resonance or local resonance will cause discomfort and injury. An obvious example is that in a nightclub, the subwoofer emits 40Hz~20Hz energy, which causes local resonance in the human chest. If some people are sensitive to sound and the resonance frequency of body structure is high, it will easily cause chest discomfort, so try to avoid appearing in places with more low-frequency energy, such as nightclubs, performance places, KTV, square dance places and so on. Last but not least, the vibration or displacement of chest organs or tissues leads to chest discomfort. If the heart is equipped with electronic devices such as pacemakers, it is strongly recommended not to be exposed to low-frequency high sound pressure levels for a long time.