An ‘open’ hearing aid is one that keeps your ear canal open.
A ‘closed’ hearing aid is one that seals your ear canal with a tightly fitting custom mould or rubber/silicone earplug, allowing little air in or out.
2. Effects of open hearing aids on sound quality
Open hearing aids are useful for early intervention for people with mild to moderate hearing loss. They amplify high-frequency sounds while still allowing low-frequency sounds to enter the ear naturally. This configuration helps the user maintain spatial awareness and natural sound quality, making the transition to using a hearing aid easier.
In the real world, open hearing aids typically provide more natural sound quality because they don't block the ear canal. By combining natural sound with amplified sound, open hearing aids create a more balanced listening experience.
Open hearing aids prevent the occlusion effect, the sensation of hearing your own voice as if you were talking into a bucket.
The occlusion effect (also known as the plugged ear effect), where the user has the sensation of hearing their voice as if they were hearing it in a barrel when wearing hearing aids or earplugs or headphones. After wearing hearing aids, the user's own chewing, swallowing, talking and breathing sounds will go through bone conduction causing the outer ear canal wall to vibrate, and the low frequency part of it will be amplified because of the occlusion effect, the sound can not leave from the ear canal, and constantly transmitted to the ear drums, the user will constantly hear the sound that is both noisy and hollow.
3. Hearing in noise
Open hearing aids can be problematic in noisy environments because they allow background noise to enter the ear along with the amplified signal. Therefore users with a slightly more severe hearing loss or those who need to perform daily activities in some very noisy environments are recommended to use closed hearing aids.