In recent years, open Hearing aid Gradually received.One advantage of open fitting is appearance, which is also a key concern for most users.For RIC behind-the-earHearing aid, Because the receiver is in the ear canal, not inside the hearing aid shell, its back-of-the-ear part is relatively small and exquisite, which makes the hearing aid more invisible.The thin wires and tubes of the back-of-the-ear casing connected to the receiver in the ear canal are thinner and more beautiful than the traditional ear mold sound tube.The ear canal end of the receiver is equipped with a special anti-earwax membrane device that can significantly improve the comfort and reliability of the hearing aid for the hearing aid wearer during outdoor sports or other activities where the hearing aid is surrounded by tides.
In addition to aesthetics and ease of use, RIC hearing aids also have important acoustic advantages:
1) High frequency enhancement
Increasing high frequency gain is the ideal result of open fitting. Mueller
and Ricketts proved that the residual resonance effect of the ear canal can increase the high-frequency gain, and the residual resonance response of the ear canal is usually 2000-3000
Between Hz-the frequency range important for speech understanding.In this area, less gain is needed to reach the ideal sound pressure level of the ear canal, which is especially important in the presence of background noise.
2) Reduce ear plugging effect
In addition to improving high-frequency amplification, another major advantage of in-ear receiver technology is to reduce ear plugging effects.The ear plugging effect is usually described as “echoes” in your voice, which is very annoying, and some people give up wearing itHearing aid.The plugging effect refers to the enhancement of the low-frequency sound pressure level in the ear canal.It is worth noting that the plugging effect of wearing open earplugs is negligible. Even if tightly closed earplugs are used, the average plugging effect is less than 2-3
dB.For most patients, this value is not annoying or even noticeable.
3) Smooth frequency response
Sound quality has a direct relationship with frequency response.The coupling system of the ear receiver can optimize the smooth response and expand its high-frequency amplification response.
4) Feedback stability
The maximum insertion gain is actually the maximum gain tested when the hearing aid does not have feedback. To make full use of this gain, the critical gain (or maximum stable gain) must be greater than the maximum insertion gain.For any open option, the risk of feedback is higher than that of the closed option.The risk of feedback requires an effective feedback elimination system.
The current feedback cancellation system of high-end hearing aids can provide 10-20
Additional stabilization gain of dB.Influencing factors include individualsHearing loss, Individual anatomy results and acoustic environment.Due to the daily life environment (such as chewing or being close to a window), the feedback path can vary up to 20
dB, OLG optimization and adaptive feedback cancellation system ensure that most patients enjoy feedback-free listening in daily life.