Why can hearing aids whistle?

If you have hearing aids or know someone who does, then you most likely have heard the whistle of a hearing aid. The cause of this sound boils down to the concept of feedback. Read on for some tips and tricks!

Some feedback on your feedback

That whistle is called feedback. It occurs when the sound from the speaker of the hearing aid (the speaker is in your ear canal) leaks out and gets picked up by the microphone of the hearing aid. This sound then gets re-amplified by the aid and produced by the speaker again, but louder. This louder sound then is at risk of leaking out and getting picked up by the microphones again. This cycle creates a feedback loop and you hear it as the hearing aid whistling.

When does it happen?

When you first get new hearing aids there can be some feedback until we make certain adjustments to help limit it.  But even with those adjustments, if you take your hand and completely cup it over your ear you will probably hear some whistles. Perhaps if you are laying down and turn your head to one side it could also happen. The reason for this is because any sound that is still leaking out of your ear will reflect off any nearby surface and return to the microphone. 

You can also get this same effect by holding the hearing aid in your hand and closing it over.  Depending on your hearing loss, even leaving the hearing aid on the table could cause it to feedback. So remember to turn your hearing aid off when your not wearing it!

What can be done about it?

There are a few things to consider if you have feedback.

  • Make sure your hearing aid is properly inserted in your ear. If not, there is an increased chance of sound leaking out and therefore a greater risk of feedback.
  • Get your ears checked for wax. Wax buildup can reflect sound off the wax back out of the ear to the microphones.

Reducing feedback

Hearing aids today are much better at reducing the risk of feedback. Traditionally the only way to limit it was to turn the hearing aid down, which can compromise your ability to hear.

Instead, consider a visit your audiologist if you need assistance with this issue as there are better solutions these days thanks to improved hearing aid technology.