Hearing aids, especially modern aids of today, pack a lot of technology into a very small device. Hearing aids can be thought of as a personal public address system shrunk down into a tiny package. Hearing aids vary in size and style, however, all of them operate in similar ways for their basic functions. Most hearing aids also contain additional features, add-ons, and technology, which have more variation in the way that they work.
Basic Hearing Aid Components and Process
All hearing aids, regardless of style, will contain four basic components. These components will vary in size, shape, and type, however, they will always be present in every hearing aid. The four core components include a microphone, amplifier, speaker, and power supply. Aside for the power supply, each of the four components work in successive order, following a specific process in order to improve your hearing and understanding.
- Microphone – First, sound waves are recognized and collected by the microphone component of your hearing aid. The microphone then transmits these sound waves into electric signals to be sent to the amplifier.
- Amplifier – The amplifier plays a few different roles in the process. The amplifier gets its name from older analog hearing aids, where the amplifier simply received the signals from the microphone and processed all the sounds at a louder frequency. Since most hearing aids of today are digital, the amplifier now plays a variety of roles. It is the amplifier that processes different sounds differently. Most hearing aids can determine the difference between sounds such as speech, background noises, or music and can amplify or lessen these sounds as necessary. The amplifier then sends these modified electric signals to the speaker.
- Speaker – The speaker sits within the ear, and it is the part of the hearing aid that directs the amplified and modified sounds directly to your inner ear in order for your ears to “hear” and your brain to process.
- Power Supply – All hearing aids need a way to keep themselves running. Hearing aids of today typically either use a zinc-air button disposable battery and/or rechargeable batteries along with a charging port.
More Complex Hearing Aid Capabilities and Processes
All hearing aids are similar in that they will run sounds through the basic system above in order to operate. Where hearing aids will differ is in their more complex audio processing systems. The system(s) used by any one particular hearing aid will vary depending on the manufacturer, performance level, and feature availability.
- Gain Adjustment – Gain adjustment refers to an amplifier’s ability to selectively increase or decrease specific frequencies. These gain frequencies are typically adjusted to match an individual’s specific hearing loss. Gain adjustment is similar to the graphic equalizer on a stereo that allows listeners to adjust specific frequencies such as speech, bass or treble.
- Compression – There are many different types of compression, and it is quite a complex topic. A person with normal hearing is able to identify and understand the full range of sounds from softest – such as a light breeze to the loudest – such as a helicopter landing nearby. A person with hearing loss is only able to identify and understand a much more restricted range of frequencies. Hearing aids with compression technology are able to squeeze the entire range of sounds humans are capable of hearing into the smaller range of sounds the individual can hear. Of course, this technology takes into account the fact that some sounds are more important and need to be more amplified than unnecessary background noises.
- Sound Classification – Sound classification is similar to gain adjustment; however, it categorizes sounds based on type rather than frequency. This includes speech, music, traffic noises, TV and so on. Advanced hearing aids that use sound classification systems are able to use the sounds around you to determine where you are – church choir, gym, home, etc. and adjust the specific sounds accordingly. For example, when at a concert hall, sound classification systems may amplify sounds it identifies as music more loudly than when it identifies music that is simply background noise at a party.