Helping a senior person with hearing aids. (I wear them too.) Trying to understand the reason for whistling or feedback. She has custom molds and she gets the whistling when putting in the aids but it has happened a couple time seemingly out of the blue. My gut tells me there’s too much amplification of some frequencies. They tried making the vent holes larger, but it didn’t solve the problem. Is this the same as occlusion? Some people can’t wear custom molds because of occlusion…is it the same for the whistling, or are they 2 different things?
Welcome to the forum @Louaberg , yes occlusionand feedback are 2 different things, the most common reason for feedback is sounds are leaking out from the moulds, they need to be a tight fit with a canal lock to keep them from moving around,
They tried making the vent holes larger, but it didn’t solve the problem
This is definitely not the way to fix feedback, of course it’s for occlusion which some people can’t tolerate.
Some more information on the custom molds and would be helpful for everyone.
Feedback happens when sound from the hearing aid’s receiver escapes the ear canal and loops back into the device’s microphone. It’s physics, not so much about the hearing aid.
You can fix this by improving the mold’s seal, like reducing the vent size to prevent sound leakage and ensuring the molds are properly inserted (also check that the are not dirty). Lowering the gain (amplification) can also reduce feedback, but it will make the hearing aids less effective—less amplification means less help from them. “Too much amplification” does not make sense if that level of amplification is what the person needs.
Occlusion happens when the ear canal is sealed and a person has good low-frequency hearing, much like plugging your ears with your fingers. It’s not about using molds but rather about the size of the vent—larger vents reduce occlusion.
This creates a dilemma: larger vents can cause feedback, while smaller vents can lead to occlusion. The specialist’s role is to strike the right balance that, along with the necessary amplification, helps the client hear more clearly.
As @tenkan mentioned, sharing the along with mold details (such as type and vent size) can help others offer more specific and useful advice. If the person is having feedback issues, that person should talk to the fitter.
Thank you for the explanation. I obviously didn’t understand what causes feedback. I don’t have the . I will go with her to her next appointment later this week, I believe she has silicone molds and she does have trouble getting them in her ears. I believe it’s a dexterity issue.
Thank you! I need to follow up with the fitter. I now understand better. I now think that the feedback is caused by molds not sealing properly because of dexterity issues. She doesn’t like putting them in her ears. I go with her to see the fitter in a couple days, Hopefully we will get some help.
Whistling and occlusion are actually two different issues: feedback happens when sound leaks out of the ear canal and gets re-amplified by the microphone. In contrast, occlusion is that “talking in a barrel” feeling caused by trapped sound waves. Since making the vent holes larger usually increases sound leakage, it likely made the whistling worse rather than fixing it. The random whistling out of the blue is usually caused by a poor fit/seal of the custom mold, a buildup of earwax, or the aid simply being pushed against a surface like a hand or pillow.
Hearing aids have feedback suppression in the software. But setting it too high can affect audibility, so you want to reduce the physical feedback path as much as possible before raising the software setting.
Super! I was just thinking (after reading previous posts here) that making the vent holes bigger was working against the effort to stop the whistling. But I know why the fitter did this. It’s because her hearing has improved (in the low frequencies more so) since she is being effectively treated for a chronic infection. I am sure this causes opposing challenges for the fitter. It seems to me that acrylic molds might be better for her. They would be less friction and they would (hopefully) slide into the ear canal better. The vents were made larger because her low frequency hearing improved. (Program changes and also happened at this time.)
New related question. Why does she hear the feedback when trying to put the custom molds in but before it’s even in her ear…and when no one is talking.
Feedback happens when sound from the hearing aid’s receiver escapes the ear canal and loops back into the device’s microphone. It’s physics, not so much about the hearing aid.
As my previous comment already explained, feedback occurs when the sound produced by the hearing aid reaches its microphones.
Why does she hear the feedback when trying to put the custom molds in but before it’s even in her ear…and when no one is talking.
As above, also Rechargeable are set to turn on as soon as they are removed from the charger by default, you can change this and also set a delay, obviously disposal use the battery door to turn on or off.
Sorry, I am not understanding. If no one is talking, then are we talking about general background noise getting to the microphones? In which case, it’s not necessarily the fit of the molds.
I guess I assumed that the noise hitting the mics which produces the feedback were voices. We purposely were quiet and it still screeched before she got them in her ears.
Even when you feel the environment is quiet, there are sounds (some that you cannot hear). These sounds are amplified by the aids and, if any sound from the receiver reaches the mics, the aids will whistle. Any sound that loops into the device that generated the noise causes feedback, it’s physics.
Have you ever been to a conference or a church when an annoying sounds appears when the speaker turns on the mic, even when the speaker is not talking?
As above, also Rechargeable are set to turn on as soon as they are removed from the charger by default, you can change this and also set a delay, obviously disposal use the battery door to turn on or off.
Why has no one mentioned Feedback Manager settings?
IMO, relying solely on the feedback manager is insufficient when dealing with a physical sound leakage issue. You need to adddress the root cause.
Feedback managers work in ways like these: (1) by reducing the volume (sound clipping) which decreases the gains at that frequency, thereby reducing the effectiveness of the hearing aid; or (2) by shifting that sound to an adjacent frequency, which can create sound distortion and other artifacts. This means that the hearing aid feedback manager is useful for occasional situations that last a very short time, such as a quick hug.
She has custom molds and she gets the whistling when putting in the aids but it has happened a couple time seemingly out of the blue. My gut tells me there’s too much amplification of some frequencies. They tried making the vent holes larger,
