Features of Modern Hearing Aids
How Hearing Aids Work
In a very basic sense, a hearing aid is an amplifier that amplifies external sound. That is a very basic description and it doesn’t cover all of the things that hearing aid does, however, it is a good start point for your understanding. Let’s take a look at how a hearing aid works and talk about some of the different strategies and features that modern hearing aids use to help you hear better.
We Need Microphones
Let’s start at the beginning. In order to capture external sound, we need microphones, and two is always better than one. The microphones used in hearing aids have evolved and changed over the years, however, the real evolution has been in how the signal processing within digital hearing aids handles the sound from those microphones. One microphone gives us one sound reference, but two, gives us two separate sound references to work with. The advent of dual mics allowed hearing aid brands to introduce directionality. Directionality is a strategy in microphones that allows the emphasis or focus of the microphones to be in one direction. In the case of hearing aids, usually to the front.
This allows us to help people hear better in noisy situations because usually, the sound signal they want to listen to is to the front. In essence, the microphones pick up the sound from everywhere, but the digital brain of the hearing aid actually does the real magic. The microphone is the first part of the chain though. Let’s take a look at what happens with the sound captured.
Chips, But No Fish
The nerve centre of any digital hearing aid is, in fact, the chip buried inside it. What most brands refer to as a chipset and what many hearing aids professionals refer to as the amplifier. To call it an amplifier is really doing it a disservice, although, in fairness, that is one function of the chip. The computer brain of modern hearing aids are advanced computing devices that are similar in nature to the chips in your phone, tablet or computer. They are just dedicated to running strategies and features that are all about manipulating sound to help someone hear better.
Basically, the chip runs the operating system of the hearing aids, the features that help you hear better can be thought of as apps if that makes sense. The core operating system is designed to take the sound input and manipulate it so that it can then be played into your ear in a way that helps you hear the sounds that you can no longer hear normally. While this is fantastic for situations where there is no competing noise, often it isn’t enough in those noisy situations. This is where the added apps begin to help, for instance, a noise reduction app helps to reduce the background noise by trying to turn it down without affecting speech.
A directional app takes the sound coming from the microphones and focuses on sound coming from the front of the user. In this way, different apps help you hear better in different situations. The higher the technology level of the hearing aids you buy, the better the app is at doing what it needs to do. Once the manipulation of sound is finished, we then need to get it into your ear, which brings us to ...
The speaker, which is called the receiver by professionals just to confuse you, is the very last part of the chain. The manipulated sound is played to you through the receiver into your ear. Different receivers offer different benefits, it can be bandwidth which means the frequencies of sound that can be replicated. The higher the frequencies of sound the better for you, it delivers better clarity. Different receivers also offer different power levels, higher power levels are more important for greater hearing losses.
As you can see, there is a lot going on in a modern hearing aid to help you hear better.
The YouTube video by Signia shows the components and inner workings of a hearing aid.