The cochlea feels the sound in different frequency bands. At the tip of the cochlea, it feels low frequency sounds, i.e. coarse sounds; at the bottom of the cochlea, it feels high frequency sounds, i.e. sharp sounds, like cicadas, whistles and bells. The sound of musical instruments is rich, but it mainly damages our high frequency hearing. Clinically, we see many patients who come in with tinnitus or deafness and often it can be found that they have had recent or previous noise exposure. In the process of hearing test, we can find that the hearing curve has the characteristics of noise-induced hearing damage, which is a “V” or “U” shaped hearing loss in the high frequency area, which is what we call professionally The 4000 Hz “hearing valley”. This 4000 Hz “hearing valley” is more common, but some people have hearing loss in the 2000, 3000, or 6000 Hz band. This hearing valley is characteristic of the hearing curve of noise deafness, and can be seen as an early sign of noise deafness. The loss of cut marks can be very shallow or very deep to determine the degree of deafness. In the early stage, it is important to pay attention to a very small notch, and our doctor will tell the patient to get out of the noise environment and pay attention to hearing protection after finding the notch.