Anyone who has worn a hearing aid knows that while the device works well in quiet environments, it can struggle to pick out speech from the surrounding noise in a busy or noisy environment. Noise reduction is an important indicator of a hearing aid’s quality, so how should you choose one?
Many users have noticed that the clarity of speech in the fitting room is much better than in a noisy street environment. This difference arises because environmental noise interferes with speech, making it hard to hear clearly even if you can hear sound. To address this, we must discuss hearing aid noise reduction technologies, which are one of the key factors behind price differences among devices.
Old Hearing Aid Noise Reduction Technology
Older hearing aids, due to limitations in chip technology, were not able to fully distinguish between speech and noise. They typically used basic multi-channel compression. In simple terms, since noise often originates from low frequencies, these devices automatically reduce amplification of low-frequency sounds in noisy modes, essentially “filtering out” some of the noise.
This approach makes listening more comfortable but can also filter out speech that is similar to low-frequency noise. As a result, the clarity of speech is not fully maximized, reducing the overall quality of sound reproduction.
New Hearing Aid Noise Reduction Technologies
With the development of smart chip technology, modern hearing aids now use more advanced and diverse noise reduction techniques, which combine several technologies, including noise suppression (chip technology) and microphone technology.
1. Noise Suppression
Noise suppression is the standard noise reduction technology used in modern hearing aids. Unlike older devices, new models analyze and differentiate between speech and noise using digital signal processing in both time and amplitude domains. The processor then reduces amplification for noise and enhances amplification for speech, rather than indiscriminately compressing all sounds.
However, as user demands for quality of life have increased, basic noise suppression can no longer meet everyone’s needs. In very noisy and complex environments, while the noise may become softer, speech enhancement may still be insufficient. Many users still struggle to understand speech in challenging auditory environments.
2. Microphone Technologies
Microphone technology plays a critical role in improving hearing aid performance in noisy environments. Here are some of the key types of microphones used in modern hearing aids:
(1) Fixed Directional Microphones
In everyday life, noise may come from the front, back, or sides. Many hearing aids are equipped with directional microphones or microphones that can automatically identify the primary sound source. These microphones amplify sounds from the front, which is where the user typically communicates, while reducing sounds from the sides and back, effectively suppressing unwanted noise.
With some experience, users can adjust their head position in noisy environments to minimize background noise. For instance, in a noisy restaurant, users can shift their chair to reduce the noise from the kitchen or other sources.
(2) Automatic Directional Microphones
Most children’s hearing aids now feature automatic directional microphones. Since children may lack the listening experience to make manual adjustments, these microphones automatically select and amplify sounds from the front, while reducing background noise. The quality of this functionality depends on the sophistication of the technology used.
(3) Adaptive Directionality (Multi-Channel)
This feature, found in many mid- to high-end models, adjusts the microphone’s directionality based on the environment. Adaptive directional microphones not only adjust the microphone’s focus automatically but also identify the noise source and suppress it. Some advanced models can track multiple noise sources and simultaneously reduce them.
(4) Omnidirectional Microphones
In some specific situations, directional microphones may not be the best option. For example, when driving, if the hearing aid focuses on reducing noise from the rear, it may limit the ability to hear passengers in the back. Omnidirectional microphones allow users to hear sounds from all directions equally, providing a better experience in environments like music halls where sound comes from multiple directions. In these settings, the device may automatically switch to omnidirectional mode to optimize the listening experience.
(5) Customized Hearing Aids with Directional Microphones
Some custom-fit hearing aids, such as deep ear canal devices, may have limited space for more complex microphone functions. In these cases, users rely more on the structure of their outer ear to adjust sound direction and quality, which may not be as effective at identifying and amplifying speech.
Can Noise Be Completely Eliminated?
Currently, no hearing aid can completely eliminate all noise or fully replicate the hearing experience of a normal ear. However, it’s essential to remember that even people with normal hearing live in noisy environments and must engage in conversations amid ambient noise. Noise is a part of our daily lives, and just as normal-hearing individuals struggle with noise, hearing aid users face similar challenges. Realistic expectations about noise reduction are key to satisfaction with any hearing aid.
It’s also worth noting that hearing aids with better noise reduction technology are often priced higher. Therefore, finding a device that matches the user’s needs will provide the best value.
ECMIC Microphone Components for Hearing Aids
Hearing aid microphone (ECM-B4015AML39-733) for enhanced sound clarity in noisy environments
At ECMIC, we specialize in producing high-quality electret microphones, such as the ECM-B4015AML39-733, designed specifically for hearing aid applications. With features like high sensitivity (-39dB) and excellent signal-to-noise ratio (74dB), our microphones offer superior sound clarity and enhanced speech recognition, even in challenging noise environments. These microphones are built to provide clear, consistent sound quality, contributing to a better hearing aid experience.
For more information on our microphone components and how they can improve your hearing aid design, contact us today.
