Invisible hearing aid (IIC) is a noble product among hearing aids. The invisible hearing aid defined by international standards only refers to IIC and does not include ITE, ITC, CIC, etc., let alone BTE devices. So, why are invisible hearing aids so popular with some consumers?
1. The appearance is not visible
This is the biggest advantage of invisible hearing aids. Many people choose invisible hearing aids because they are “invisible”. In addition, due to appearance and location, invisible hearing aids have many advantages in acoustics.
2. Reduce ear plugging effect
When a person speaks, the sound waves generated by the resonance of the spine part of the external auditory canal wall leak out, and the sound waves generated by the vibration of the bones replace. Invisible hearing aids are located in the deep part of the ear canal (mainly the bones of the external auditory canal), which can reduce the ear plugging effect.
Fitting technicians also need to pay attention when fitting hearing aids because the sound outlet of IIC is closer to the tympanic membrane, so when selecting hearing aid parameters, the gain can be reduced by 3dB on the basis of CIC.
3. Mirror effect
The so-called mirror effect refers to the ear contour effect.
The ear contour can increase the mid-high frequency sound, attenuate and increase the sound. If the ear contour exceeds 2000 Hz, the gain increases with the increase of the transmission frequency. This is the pinna effect. The pinna effect is related to its measuring point. If it is measured at the microphone position of the invisible hearing aid, then this effect is obvious. This phenomenon is actually very stable.
Related to the auricle is the Helmholtz resonance effect.
4. Helm Holtz resonance effect
The auricle has the function of reflecting and refracting sound waves. When the sound enters the ear canal, the sound pressure increases between 4000~5000Hz, and there is a resonance of 6~8dB. This means that the sound within this range has been amplified before entering the microphone. The invisible hearing aid is located in the deep part of the ear canal and does not affect the resonance function of the concha cavity.
Therefore, the invisible hearing aid has a better compensation effect for high frequencies and can enhance the hearing aid effect of the high-frequency sound range.
5. Balloon effect
The invisible hearing aid is located in the deep part of the ear canal, which causes the volume of the external ear canal to shift. According to the relationship between pressure and volume, the volume is distributed, and the pressure increases. Therefore, it is generally believed that the volume output of the invisible hearing aid is 5dB higher than that of the ear canal hearing aid of the same power, and the high-frequency output is 10-17dB higher.
Post time: May-06-2021