The bone conduction hearing aid makes you audible and audible. The so-called air conduction hearing aid is essentially a sound enhancer. When the ambient sound intensity is not enough to make the hearing loss sound, the sound is amplified by means of a hearing aid. Then pass it to the tympanic membrane. However, the gas-conducting hearing aid does not change the conduction path of the sound, and it is not suitable for some symptoms. For example, patients with ear canal atresia, perforation of eardrum, mechanical damage to small bones, inflammation of the ear canal, and blockage of ear canal secretions. Studies have shown that a significant number of hearing aid users feel "noisy" with gas-conducting hearing aids and are reluctant to wear them.
It is worth noting that the current level of air conduction hearing aid technology is relatively high, especially after the adoption of digital processing technology, the ability of air conduction hearing aid to process speech is greatly improved, and the gas conduction hearing aid itself is not "noisy", but this type Older people do not adapt to such hearing aids. The reason is that organ aging (such as tympanic membrane collapse) causes sound variability, that is, the sound that has been heard has changed, called auditory distortion. Old people with hearing distortion can not only hear the sound, but may lead to irritability and unsociable personality. This is the reason why the elderly often say "noisy" and are unwilling to use air conduction hearing aids in more noisy environments. The best way to solve this type of problem is to use a bone conduction hearing aid.
The so-called bone conduction hearing aid is a hearing aid that senses sound based on the vibration of the skull. For example, I can hear my own teeth, and I hear my own speech all belong to the sound of the skull. Because the human skull is used to perceive the sound, the aging or lesion of the auditory organ generally does not affect the sound conduction, and the hearing aid effect is often better. The principle of the bone conduction hearing aid is basically the same as that of the gas conduction hearing aid. The microphone is used to pick up the ambient sound and the digital processor processes the speaker to work. However, there are some essential differences between bone conduction hearing aids and gas conduction hearing aids: First, the speakers used are different. The hearing threshold of the bone is variable. It is required to reach 70dB or more in the low frequency band (about 500Hz), and only 30dB in the 2100 Hz or so can meet the requirements. It is different from the hearing threshold of the ear. Therefore, the speaker and the air conduction hearing aid used in the bone conduction hearing aid are used. The speakers used are completely different. Bone conduction hearing aids need to design bone conduction speakers in accordance with the hearing threshold requirements of the bone. Second, digital processing techniques are different. Since the frequency response of the bone is completely different from the frequency response of the ear, it is completely different in digital processing technology. Bone conduction hearing aids need to design channels and configuration parameters in accordance with the frequency response of the bone. Third, the power of the speakers is different. The energy of the bone conduction speaker must match the needs of the skull to sense the sound. The maximum output power of the extremely powerful gas-conducting hearing aid is only about 30mw. This energy value can only be felt by the eardrum, far from meeting the needs of the skull. The maximum output power of the bone conduction hearing aid can reach 500mw, which is different from the hammer hitting the desktop and the feather hitting the desktop. Tests have shown that the output power can only be called the true bone conduction hearing aid if it reaches 400mw or more. Therefore, although the principle of the bone conduction hearing aid and the air conduction hearing aid are the same, the difference between the bone conduction hearing aid and the gas conduction hearing aid is relatively large due to the difference in the requirements for using the ear to listen to and using the bone. When the auditory organs are aging, or the auditory organs are diseased, the ability to acquire sound depending on the vibration of the air is reduced, and the advantage of bone conduction is apparent. The bone conduction hearing aid is directly transmitted into the inner ear, which avoids the secondary damage of the tympanic membrane and the ossicular chain caused by the high gain of the air conduction hearing aid, and has a certain protective effect on the hearing. The bone conduction hearing aid can solve the problem that you can't hear, and can also help you to eliminate the inaudible troubles. However, it should be noted that the hearing aid is just a hearing aid device, and can't compare with your real ear. There is no hearing solution that can completely replace the real ear.