Newbie with Warble/Reverb Question

Hearing Aids
#11

“It does sound like entrainment you are experiencing. The hearing aids were using an obsolete method of trying not to whistle (feedback) and in doing so they sometimes confuse themselves when they hear certain noises, and ‘panic’ adjusting themselves in such a way they end up making stupid noises as you describe. The good news is that modern hearing aids shouldn’t suffer from this problem. Those Audibel aids sound like they need some adjustment to get the best sound.”

I think we have a problem with semantics here. There are two different effects that I’ve noticed with the Phonak Naida that I wear in my left ear (I have a CI in the right ear).

The first effect is a “rushing” type sound that trails each instance of sound input. When the sound input stops, the rushing continues for a few seconds and then stops. It’s extremely irritating.

The second effect, which I described in my earlier post in this thread, is a “warbling” effect. It is not a sound in itself, but a distortion of sustained sound input (mostly music). It makes me think of an underwater “bubbling” effect. As Lola Hagerty said earlier in this thread, it makes listening to music almost impossible.

#12

We are English but have lived in France for many years. Paris is a lovely city.
Regards,

#13

The first problem sounds like the aid adjusting itself when it detects a sound. This should be seamless to the user, and I don’t know what they can do about that problem since I am not an expert on that brand. Heck, I know very little about Phonak except every time I have switched a patient out of one an into a Starkey they have thanked me for it.

The second problem is entrainment. The sustained sound, like a musical note, is being perceived by the hearing aid as feedback. In adjusting itself to try and remove the ‘feedback’ the aid ends up corrupting the musical note that set it off.

This is a hallmark of an antiquated system of feedback suppression, and your best bet is to have the hearing professional turn it off, or trade the aid for something more modern.

#14

Ah cool. I can’t imagine moving to a country where they speak another language. I mean sure American English isn’t the same as British English, but it is more similar than French!

In any case, these days they have great electronic translators, which will make our first trip a little less scary! Should be fun.

#15

I am sure that if Starkey was an open platform, there are some developers in the public that could improve things too.

The major manufacturers insist on keeping their platform (both firmware & the adjusting software) tightly closed. If you could convinced Starkey to use an open platform, people would have more tendency to agree with that statement.

#16

I returned the Phonak Ambra after 3 months. They couldn’t tweak out the warble (like hearing through a whirring fan). My audi (good woman) loaned me a pair of Phonak Naida V UP (high powered with 675 batteries). Good strong aids, but the warble is still there. Consulted with a Siemens rep and tried their Nitro 700 - high powered. Same problem. He attempted to tweak it out and couldn’t do it. I think I’m going to try Oticon and see what they do.

I have a profound hearing loss and here’s what I’m beginning to wonder. Are the hearing aid manufacturers catering to baby boomers who are all just starting to lose hearing (mildly) - giving them lots of bells and whistles? That’s where the money is. But in the process, are they creating devices that don’t work well for the ones with profound loss who REALLY need them? I’ve been wearing hearing aids for 49 years and have never before encountered this issue. Any one out there wondering the same thing?

#17

I don’t think that there is any doubt that the manufacturers are trying a ‘one size fits all’ policy by trying to jam as many ‘extras’ into the product in an attempt to stay ahead of the competition. Unfortunately, the down stream end of the supply chain has not, in many instances, kept up with the technical complexities of the product. I think that the Spice chip has been a good example of this problem.
I also gave up on the Spice chip after 4 months with 2 different audis and settled for the Widex Clear 440. I think that this is a slightly less sophisticated product doing far less ‘signal processing’ but giving excellent clarity of sound. You might want to take a look!

#18

When I have patients that seem to have the exact same problem, but with 2 completely different hearing aids I tend to lean more towards the thought that it’s not an issue with the hearing aid, but something that is happening within the wearer’s ear. If it was an issue with how the chip is working/processing sound, then, theoretically, when you switch to a different company with completely different chips/sound processing, the issue should go away or at least change to a different type of problem.

Not so say that there isn’t a hearing aid out there that will work for you without the sound quality issue you are having, but putting it all on the device is missing the mark a bit. This is even more an issue sometimes in profound losses which can have some seriously funky things going on in the cochlea.

#19

If this is prevalent with severe/profound losses, bet the ranch it is a feedback issue.

As the anti feedback system kicks in it often creates an oscillating gain change that is perceived as a warble. (electronic time constants in the anti-feedback system determine the warble frequency)
The fact that a patient experienced this warble wiih two different brands is not surprising as the sound leakage could be the same.

New long tight molds could cure this. Ed

#20

Phonak doesn’t use gain applications to reduce/eliminate feedback, they use phase cancellation…so at least for the Phonak hearing aid, it’s unlikely that it was feedback.

#21

My audi could hear it through her stethiscope too. It’s definately the aids.

#22

Interesting. possibly distortion due to the high gain???

#23

Doc A: As I understand it all anti-feedback all brands systems use 180 degree phase cancellation. The problem circuit wise is to get exactly 180 degrees at exactly the reverse amplitude at the exact frequency.

The problem comes about when the system overshoots any of the negative parameters.

Yes over driving into non-linear operation could cause this instability with the gain flucturating (warble) up and down. Ed

#24

I’ve purchased the Widex Clear 440 Fusion aids after a 1 week trial. They have no warble and music is fabulous and absolutely no feedback. I still need more volume in the telecoil and I hear a snap when doors close - minor tweaks. They’re smaller and seem fragile with the receiver in the ear. Clarity is pretty good and I think will be better when that snap gets tweaked out. These aids were pretty pricey even through HearPO. I paid $2,595 per aid (let’s get the money part out in the open). The Widex rep told me about the Widex Supers coming out soon in the states - more gain and uses 675 batteries. I’m hoping to work out a trade in the future. :slight_smile:

#25

Glad you like them. I have had mine now for a couple of months and no complaints!

#26

No, there are three or four methods in use. Phase cancelling is just one.

#27

I too am in trial on Phonak Ambras and am experiencing considerable warble…sounds like speaking underwater. My audi thought it might be the Sound Recover so he inserted a program with it turned off and I still have warbling/undulating voices, especially with music. I am probably handing them back in next week to trial something else. Audi wants to try next the Widex Clear super power. I have severe loss and wearing BTE with custom molds.

#28

To clarify some of the speculation in this thread:

The warble, or distortion, that occurs with a tonal input to the hearing aid is most likely the result of an interaction between that tonal sound and the feedback cancellation algorithm.

This warbling distortion is often called entrainment. The sound can be heard by anyone listening to the hearing aids. Many sounds will cause entrainment, door bells, some voices, and music.

A hearing aid is more likely to entrain when the system is close to feedback. This means that higher gain fittings that are not well occcluded are at greater risk for entrainment. Moving to a more occluded fitting or reducing gain will reduce the extent of entrainment, it’s unlikely that this will completely eliminate it.

How to get rid of entrainment:

Most of today’s hearing aids offer different feedback canceller settings. Moving the settings from fast to slow, or adaptive to static, or high to low should all reduce the extent of entrainment. Turning the feedback canceller off should eliminate the problem (not the preferred option).

Why does this happen:

In short, the hearing aid thinks that the tonal input is a form of feedback. The feedback canceller identifies the tonal sound and attacks it. Because this is not true feedback distortion results.

Today’s feedback cancellers:

All of today’s leading feedback cancellers use phase (sound) cancellation. Please note that the phase cancellation is far more robust than simply adding a phase inverted copy of the whistle. This is what makes today’s hearing aid fittings (comparatively) stable and allows for an impressive range of open fittings. A second layer of feedback management is gain restriction. At least one company uses gain restriction that occurs dynamically during wear and most use gain restrictions that are placed (and remain fixed) at the time of fitting.

#29

Thanks Research - a very interesting post!!

#30

UmBongo: Gee did miss something in class. Was always under the impression that once feedback occurred, you could of course reduce the overall gain or reduce the gain at the oscillation frequency. But that would have the patient with less than ideal responce. Educate me. Ed