Bone conduction earphone is also called bone conduction earphone, bone sense earphone, bone transmitting earphone and bone sensing earphone. It is designed and manufactured by using bone conduction, which converts sound into mechanical vibration of different frequencies, and transmits sound wave through human skull, bone labyrinth, inner ear lymph, spiral, auditory nerve and auditory center.
Bone conduction is a way of sound transmission, that is, sound is transformed into mechanical vibration of different frequencies, and sound waves are transmitted through human skull, bone labyrinth, inner ear lymph, spiral organ, auditory nerve and auditory center.
Compared with the classical sound transmission mode of sound wave generated by diaphragm, bone conduction saves many steps of sound transmission, and can achieve clear sound reduction in noisy environment, and the sound wave will not affect others because of its diffusion in the air. Bone conduction technology is divided into bone conduction loudspeaker technology and bone conduction microphone technology
(1) Bone conduction loudspeaker technology is used to send a message, which is to listen to the voice. Air conduction loudspeaker is to convert electrical signals into sound waves (vibration signals) and transmit them to the auditory nerve. The bone conduction loudspeaker is the sound wave (vibration signal) transformed by electrical signal, which is transmitted directly to the auditory nerve through the bone. The transmission medium of sound wave (vibration signal) is different.
(2) Bone conduction microphone technology is used for receiving calls, that is, collecting sound. Air conduction is the transmission of sound waves through the air to the microphone, while bone conduction is transmitted directly through the bone.
The earphones made by these bone conduction technologies are called bone conduction earphones, which are also called bone conduction earphones, osseous earphones, bone transmitting earphones and bone sensing earphones.
Bone conduction earphone can be divided into bone conduction loudspeaker technology earphone and bone conduction microphone technology earphone
（1） Bone conduction loudspeaker technology earphone:
Bone conduction technology is used to receive the speech, which is close to the bone, and the sound wave is transmitted directly to the auditory nerve through the bone. Therefore, both ears can be opened without damaging the tympanic membrane. In the field of military and civil use, facial cheek bones are generally used to conduct sound directly.
（2） Bone conduction microphone technology headset:
Bone conduction technology is used to collect sound, which is transmitted to the microphone through the bone. In the civil field, bone conduction technology is generally used to reduce noise.
Due to the need of military scene, sometimes we can’t speak loudly, and the loss rate of sound in bone conduction is far lower than that in air conduction, and bone conduction microphone technology earphone mainly uses throat bone conduction. Due to the short distance, the loss is low. A soldier needs only a very small voice to deliver exactly what he wants to say.
When we eat biscuits, we can hear the crackle of biscuits because the vibration is transmitted through our teeth and skulls to our inner ears. When we eat, drink or scratch our head, we can hear the sound of bone conduction.
实际上，早在 18 世纪，骨传导的原理就帮助双耳失聪的伟大作曲家贝多芬重新听到了美妙的音乐。贝多芬当时尝试了由乔瓦尼.菲利波.英格拉西亚发明的一项技术，他咬着一根与钢琴相连的棍子就可以听到由颚骨传来的音乐，这其实就是声音的骨传导原理的早期应用。
In fact, as early as the 18th century, the principle of bone conduction helped Beethoven, a great composer with deafness, to hear wonderful music again. Beethoven tried a technique invented by Giovanni Filippo Ingrassia. He could hear music from his jawbone by biting a stick attached to the piano. This was actually an early application of the bone conduction principle of sound.
Bone conduction technology is mainly used in military and police professional headphones, hearing aids, sports headphones and other fields.
Under normal circumstances, sound waves are transmitted to the inner ear through air conduction and bone conduction, and then vibration is generated by the internal and external lymph of the inner ear. The spiral instrument completes the sound sensing process. Then, the auditory nerve generates nerve impulses and presents them to the auditory center. After comprehensive analysis of the cerebral cortex, the sound is finally “heard”. Perhaps we still have more or less some perceptual knowledge about air conduction, but we have no idea about bone conduction. Perhaps you can see, for example, that by covering our ears with our hands and talking to ourselves, we can hear what we say no matter how small the sound is. This is the result of bone conduction.
There are two ways of bone conduction: moving and squeezing. They can stimulate the spiral organ to cause hearing. The specific conduction pathway is “sound wave skull bone labyrinth inner ear lymph spiral organ auditory nerve cerebral cortex auditory center”. Usually people don’t need to use their own skull to feel sound, but when the external and middle ear lesions hinder sound transmission, bone conduction can be used to compensate for hearing. Such as bone conduction hearing aids, bone conduction earphones and so on, is to use bone conduction to feel sound.
Most of the time, the earphones contacted are through “air conduction”, which is called “air conduction earphone”; while the earphone produced by bone conduction principle calls it “bone conduction earphone”.
Characteristics of bone conduction earphone
(1) Bone conduction loudspeaker technology earphone:
When wearing and using, both ears are opened and the ears are not blocked, which solves the discomfort of wearing in ear earphones.
At the same time, it also avoids a series of health and health problems caused by sweating in the ear when wearing earphones. Therefore, bone conduction loudspeaker earphone is very suitable for sports use.
Open ears also ensure the possibility of headphones in dangerous situations. Open both ears, use headphones can also pay attention to the changes in the surrounding environment, more safe to use.
(2) Bone conduction microphone technology headset:
Due to the short distance of collecting sound, the loss is low. It can also let the other party clearly know the instructions expressed when the volume is very small, which is mainly used in the military field.