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Woman suffering from feedback in her hearing aids covering her ears.

Does your hearing aid sound a little like a teakettle these days? A very common issue with hearing aids which can most likely be corrected is feedback. Knowing exactly how hearing aids work and what is behind that incessant whistling will get you one step closer to eliminating it. What can you do about hearing aid feedback?

How Do Hearing Aids Work?

As a basic rule, hearing aids are simply a microphone and a speaker. The speaker plays back the sound in your ear that the microphone picks up. When the microphone picks the sound up but prior to when it gets played back by the speaker, there are some sophisticated functions that happen.

After the sound is picked up by the microphone it gets converted to an electrical analog signal to be further processed. A state of the art digital signal processing chip then turns the analog signal to a digital one. The device’s sophisticated features and controls activate to amplify and clean up the sound.

The digital signal processor then transforms the signal back to analog and transmits it to a receiver. You’re ears don’t hear these electrical signals that were once a sound. The receiver converts the signal back to sound waves and transmits them through your ears. Ironically, the brain interprets sound by electrical signals, so elements in the cochlea translate it back to electrical signals for the brain to understand.

Incredibly all of this complicated functionality happens in a nanosecond. So if your hearing aid is so advanced why does it feedback?

Feedback Loops And How They Happen

Feedback occurs in other sound systems besides hearing aids. Systems that include microphones normally have some degree of feedback. The receiver generates sound which the microphone then picks up and re-amplifies. After coming into the microphone and getting processed, the receiver then transforms the signal back into a sound wave. The microphone then picks up that same sound wave again and amplifies it creating the feedback loop. To put it simply, the hearing aid is hearing itself and it doesn’t like it.

What Causes Hearing Aid Feedback?

A feedback loop might be caused by several issues. If you turn on your hearing aid while it’s still in your hand before you put it in, you will get one of the most common causes. Your hearing aid begins processing sound as soon as you hit the “on” switch. The sound coming from the receiver bounces off of your hand and then back into the microphone causing the feedback. Before you decide to switch your hearing aid on put it inside of your ear to eliminate this source of feedback.

If your hearing aids don’t fit that well, this can also cause feedback. Loose fittings have a tendency to be a problem with older hearing aids or if you’ve lost some weight since having them fitted. In that case, you need to go back to the retailer and have the piece re-adjusted so it will fit your ear properly again.

Earwax And Feedback

Earwax isn’t a friend of your hearing aids. Hearing aids usually won’t fit well if there is earwax built up on the casing. Now, feedback is once again being caused by a loose fit. Read the manual that you got with your hearing aids or contact the retailer to determine exactly how to clean earwax off without damaging the device.

Maybe It’s Just Broke

When you’ve attempted everything else but the feedback continues, this is where you head next. Feedback can definitely be caused by a broken hearing aid. The casing might have a crack in it somewhere, for example. It’s unwise to try and fix the unit yourself. Schedule an appointment with a hearing aid specialist to get a repair.

When is Feedback Not Really Feedback

You might possibly be hearing something that you think sounds like feedback but it’s really not. Some hearing aids employ sound to alert you of impending issues like a low battery. The sound should be carefully listened to. Is it a tone or a beep, or does it actually sound like feedback? Check the users-manual to see if your device comes with this feature and what other warnings you should listen for in the future.

Feedback doesn’t discriminate by brand or style. Usually, the actual cause of the feedback is pretty clear no matter what brand you have.