Sarphatistraat, 30 january 2021
door Björn Martens
Audicien Wouter de Wolf has a regular column in the monthly Tops and Tips of Hard of Hearing Amsterdam, where he answers questions from hard of hearing Amsterdammers.
A hearing aid has a range of 1.5 meters. This is often expressed in this way and should be seen as a useful range within which you can understand speech.
If the distance is greater than 1.5 meters, then the audibility is usually also less. The sound that reaches the microphones of the hearing aids is then mixed with other sounds that are nearby. The sound also gets weaker because the distance is greater.
The signal-to-noise ratio is very important. This signal-to-noise ratio is the ratio between the “signal”, that which you would like to hear, and the “noise”, everything around it, but can interfere with audibility.
A favorable signal-to-noise ratio is achieved when the speaker is closer to the microphones of the receiver. So if you are within 1.5 meters of the hearing aid user, there is a reasonable signal-to-noise ratio. Of course, this also strongly depends on the circumstances in which you find yourself. If you want to communicate in difficult crowded places, you need to get closer together.
In general you can say that for speech understanding you need to be within 1.5 meters of the other person. Incidentally, this also strongly depends on the severity of the hearing loss. Someone with a beginning hearing loss suffers much less from a bad signal-to-noise ratio than someone with severe hearing loss and probably also has a longer range. Circumstances such as ambient noise, poor acoustics also affect the range of a hearing aid.
To further improve the signal-to-noise ratio, especially in difficult conditions, you can also use solo equipment (external microphones). This enormously shortens the distance from the speaker to the microphone and reduces it to 30 cm. In this way you can easily bridge a larger distance to a distance of up to 10 to 15 meters!
If you do not want to switch to external microphones, the quality of the hearing aid itself will be discussed. A good directional microphone is important, most hearing aids are already equipped with this, but one hearing aid is certainly not the other. There are also hearing aids that let go of directionality and where the hearing aid technique is mainly aimed at amplifying speech signals as well as possible. This, too, can be an important improvement.
We recommend that you try out what is best for your specific circumstances. The better hearing aids also have a lot to offer in this area. Puzzling and trying out what fits someone best is part of the daily work of a hearing care professional.
The statement that hearing aids have a range of about 1.5 meters is certainly correct for understanding speech!
Second Opinion Hearing aids
Wouter de Wolf is an audiologist and owner of Second Opinion Hearing Instruments, based in Badhoevedorp, close to Amsterdam.
by Wouter de Wolf en Marja de Kinderen
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