Have you ever wondered how these tiny little devices are able to amplify sounds so that you can hear them well? There is quite a bit of technology that goes into them. Let’s look at this without overloading your brain with information.

With the exception if a lucky few, there are certainties in life and ones of them is that your hearing will get worse over time. It seems to be a natural course of events. It usually starts with a person cupping their ear in an effort to hear a little better and progresses from there. There was a time when people used horns held up to their ear, but that was a long time ago and it would take too many pages to explain the entire history of this technology.

Modern hearing aids are truly a wonderful example of human ingenuity. Originally hearing aids used what is called linear amplification. This sounds a bit techie, but all it really is saying is that sounds that come in the microphone are amplified and sent to a speaker to be heard. With linear amplification all sounds that come in the microphone are amplified by the same amount. When this was the only option, people that used hearing aids had a problem. No matter how loud the sound coming in was, it was amplified. The wearer could hear quiet sounds better than without hearing aids which is great. What really bothered people was with loud sounds. Can you imagine walking by a jack hammer and having that noise amplified into your ear? It would blow your ears out and probably cause serious problems. Well, for a long time that was the only option. Hearing aid users were needing to constantly change the volume levels on their hearing aids. These were simply amplifiers.

DYNAMIC RANGE

The term dynamic range is an important concept to understand. In basic terms it is the range of sounds in volume that a person can hear. Research done by Ryan M. Corey at The University of Illinois gives a great explanation of dynamic range and noise (https://publish.illinois.edu/augmentedlistening/dynamic-range-compression-and-noise/ ). When hearing loss sets in it effects the dynamic range of the hearing loss sufferer. Mr. Corey explains that good hearing aids can compress the dynamic range for the wearer. This allows them to hear quiet sounds and loud sounds in a safe manner. His work is definitely worth the time to read.

The non-linear hearing aid came out Some time after 1980. The advantage of this technology is that quieter sounds could be amplified more than the louder sounds. This was a terrific breakthrough for hearing impaired individuals. Let’s look at how this magic works. We’re not going to take you down a rabbit hole of technical jargon. We’ll keep it at a level that most people can understand.

LINEAR AMPLIFICATION

If you look at this chart of linear amplification you will notice that the output of the sound just keeps going up with the input. This means that loud sounds get amplified as much as quieter sounds. The volume will need to be adjusted all the time.

NON-LINEAR AMPLIFICATION

Hearing aids with non-linear amplification allow the user to hear louder sounds without needing to adjust the volume. In the example of walking by a jack hammer. This loud sound would not be amplified as much as quieter sounds. This breakthrough really changed the hearing aid industry and the lives or hearing aid users. The chart below will give you a better graphical explanation of this concept.

If you notice the third point on the line is where the amplification starts to adjust for the louder sounds. This is what is referred to as the knee point. This point can be programmed into the hearing aid through a computer. This is another reason that it is important to get a comprehensive hearing evaluation by a qualified professional when purchasing hearing aids.

Good hearing aids are much more than simple amplifiers. The newest technology can greatly improve your life and help preserve your hearing.

Noise Reduction

An even more interesting technology is noise reduction. This is another innovation that is possible because of non-linear amplification. With the older hearing aids that used linear amplification. The hearing aid wearer would hear all sounds equally. The sound could be generated by the person the wearer is listening to or background noise like an air conditioner or traffic even sounds in a room where multiple people are speaking. This led to frustration for the wearer and other issues.

With the advent of non-linear amplification the hearing aids can distinguish between background noise and speech over multiple frequency bands. The hearing aids can amplify speech sounds and reduce the amplification of the background noise.

It is truly amazing how these new advances in technology have helped hearing loss sufferers lead a more enjoyable life. What are you doing to preserve your hearing today so that you will have it later in life?