I wrote this article help you understand basic hearing aid features. It’s called “Hearing Aid DNA” because these features are the building blocks of all hearing aid technology.
The more advanced features a hearing aid has, the better it will perform to help you in background noise and, of course, the price goes up.
So, why would you buy a higher end hearing aid?
With this information, you’ll be better informed and able to make a wiser buying decision.
Here’s what we’ll cover:
- Directional Microphones
- Noise Reduction
- Programs & Memories
- Channels & Bands
- Feedback Cancellers
Let’s get started!
Benefit to you: Better hearing in background noise
Directional Microphones help you hear a person or sound that is in front of you when you are surrounded by noise.
Most mid to upper level hearing aids automatically sense noise and will employ the directional microphones but not all – make sure to ask before you commit to buy!
Benefit to you: Better hearing in noise & sound quality
Noise Reduction helps to control the level of noise (i.e. machines, fans, traffic, car noise, background party noise, etc.) and helps you hear what you want to hear.
When a background is comprised of noise only, effective noise reduction systems reduce the noise level to make sound more comfortable for you. When the environment is comprised of a mixture of speech AND noise, the role of noise reduction is to decrease the loudness and annoyance of the noise, without reducing available speech sounds.
Programs & Memories
Benefit to you: Access to customized settings for personal listening preferences
Programs are selectable settings on a hearing aid for different listening conditions.
They can be set so that you hear a beep or spoken message telling you that you have changed a program or setting. You can change them by pushing a button on your hearing aid or with a remote control (if your hearing aid has one).
Most mid to high level hearing aids adapt to different listening situations very well and will automatically make the necessary adjustments to ensure optimal hearing. But, there might be times when you prefer to hear on a particular setting.
You have probably seen home stereos or car stereos that have presets for different styles of music (Jazz, Rock, Pop, Vocal, etc.). Hearing aid programs can be thought of in the same way except there is, technically, a LOT more complex features being adjusted on the hearing aid.
Benefit to you: Telephone is easier and use of publicly provided loop systems
Also known as a “T-Switch” or “T-Coil”, a telecoil can provide the extra help you may need in hopelessly frustrating situations.
It’s nothing more than a tiny coil of wire around a metal core that detects and draws sound from a magnetic field (like a telephone receiver). It is very tiny and built in to the hearing aid so it’s not visible from the outside.
Basically, the telecoil picks up the signal (i.e. voice on the phone) through the magnetic field generated by the telephone receiver.
A telecoil can be switched on manually – by pressing a button on your hearing aids, or it may be set to switch on automatically when it is close enough to a telephone receiver.
Old telephones with big, heavy receivers work well with telecoils because they have a strong magnetic field. Newer telephones might not work as well unless they are “Hearing Aid Compatible”. These phones contain extra electronics to generate a magnetic signal.
Many public places like theatres, auditoriums, sports stadiums, and churches provide Assistive Listening Systems (ALS). An ALS is a system that generates a magnetic signal of the event’s audio to be picked up by the telecoil in hearing aids or by headsets loaned out to patrons.
You can also use a telecoil to hear TV, in meetings, or noisy restaurants if you supply the magnetic signal using a device like a personal neck loop or room loop.
The major advantage of using a telecoil is that you can turn off your hearing aid microphone to turn off the competing noise around you while you listen to the direct signal of who or what you want to hear.
Channels & Bands
The goal of any well-designed hearing aid is “to maximize speech understanding and sound quality”
Speech uses a variety of frequencies (pitches) with the low-pitched vowels (A, E, I, O, and U) providing loudness and high-pitched sounds (S, T, P, F, D, TH, etc.) giving clarity. Hearing loss is usually not the same across all frequencies (pitches).
As example, people who have a high-frequency hearing loss (difficulty hearing high-pitched sounds like female voices, children, and birds). This is a problem to the person because even though they can hear some sounds from the low pitch (or bass) they do not get any clarity from the missing high pitch sounds (treble).
When fitting this person with a hearing aid, we want to match the exact amount of amplification for the exact hearing loss at each precise frequency. Digital hearing aids divide the frequency/pitch range into channels (or bands).
Check out the picture above. It’s a graphic equalizer from a home stereo system. The top row of buttons is for the left side and the bottom row is for the right side. Notice that each row has 10 buttons? Each one adjusts a different part of the frequency spectrum. In other words: each side has 10 channels or bands. Some hearing aids have more channels/bands than others. Bass to the left and treble to the right… Older car radios have 2 channels – bass and treble.
Depending on your particular hearing loss, you may need more channels/bands. The number of channels you need will depend upon your type of hearing loss and the end quality of your sound.
Feedback (annoying whistling) Cancellation
If you have ever been to an event where someone speaks into a microphone of a public address (P.A.) system, you’ve probably heard feedback. It’s the annoying whistling, squealing, screeching sound that happens when the person covers up the microphone or points it in the wrong direction.
Hearing aids are a lot like miniature P.A. systems in that they have microphones, a power source (the battery), a computer chip (like a mixing board), and a speaker (or receiver).
If the sound from the hearing aid comes out of the ear canal, it can get picked up by the highly sensitive microphones and be re-amplified through the hearing aid. This is known as a feedback loop and it sounds very unpleasant.
One of the most important steps in eliminating feedback in is to have a correctly fitted ear piece that separates the microphones from the speaker in the ear. In most cases, when a hearing aid is squealing with feedback it is because of a poor physical fit and can be remedied with proper attention.
Newer open-fit styles of hearing aids are usually the most comfortable to wear because they don’t make your ears feeling plugged. However, they’re more prone to feedback because they do not offer much separation between the microphones and speaker.
Modern hearing aids use sophisticated technology to reduce and control feedback by means of the computer chip (or brain) that controls them. Manufacturers put a lot of effort into controlling feedback – and each gives their system a name. The chart below shows the name each manufacturer gives their anti-feedback system.