What are the advantages and disadvantages of invisible hearing aids?

What are the advantages and disadvantages of invisible hearing aids?

Invisible hearing aidIIC) is a noble product in hearing aids, and the invisible hearing aids defined by international standards only refer toIICDoes not includeITE,ITC,CICWait, let alone the back of the ear. 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. Doesn’t many people choose invisible hearing aids instead of “invisible”? In addition, invisible hearing aids have many acoustic advantages due to their appearance and wearing position.

2Reduce the ear plugging effect

When a person speaks, the sound waves generated by the resonance of the cartilage part of the wall of the external auditory canal are leaked, and the sound waves generated by the vibration of the bone are less, and the invisible hearing aid is located in the deep part of the ear canal (mainly the bone of the external auditory canal), which can reduce the effect of blocking the ear.

The fitter also needs to pay attention when fitting the hearing aid, becauseIICThe sound outlet is closer to the tympanic membrane, so when choosing the parameters of the hearing aid, you canCICBased on the basis, the gain is reduced3dB.

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3Mirror effect

The so-called mirror effect refers to the auricle effect.

The auricle can gain mid-high frequency sound and attenuate low-frequency sound. The auricle is greater than2000HzThe sound, which increases in gain as the frequency increases, is the auricle effect. The auricle effect is related to its measurement point. If it is measured at the microphone position of the invisible hearing aid, then this effect is obvious, and this phenomenon is actually very stable.

Related to the auricle, there is the Helmholtz resonance effect.

4Helmholtz resonance effect

The auricle has the function of reflecting and refracting sound waves. When the sound enters the ear canal,4000 ~ 5000HzBetween, the sound pressure increases, there is6~8dBResonance. That is to say, the sound is in this range and has been enlarged before entering the microphone. The invisible hearing aid is located deep in the ear canal and does not affect the resonance function of the ear cavity.

Therefore, the invisible hearing aid has a better compensation effect on the high frequency, and can enhance the hearing aid effect of the high frequency sound segment.

5Balloon effect

The invisible hearing aid is located deep in the ear canal, resulting in a decrease in the volume of the external auditory canal. According to the relationship between pressure and volume, the volume is reduced and the pressure is increased. Therefore, it is generally believed that the low-frequency output of the invisible hearing aid is higher than that of the ear canal hearing aid of the same power.5dB, high frequency output is high10~17dB.

Disadvantages of invisible hearing aids: invisible hearing aids are relatively adaptedCICLower and more expensive. In addition, because the invisible hearing aid has a very high volume requirement and is difficult to manufacture, it is also the type of hearing aid with the highest shell rework rate.