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Hearing aid distortion


mbain

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Has anyone noticed that while listening to music at reasonable sound pressure levels from usual listening position, that hearing aids are driven to distortion? I have noticed a "garbling" of especially female voices. A distortion that is subtle at first, often barely noticable, yet when perceived it makes listening unpleasant.

mbain

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Do audiophile quality hearing aids exist? If not - seems like a good idea to me. My mother has been using hearing aid for 3 years now (quite an expensive one) and I have to speak really loud to make her understand what I'm saying anyway.

Hearing aids vary at least as much as other audio equipment in quality and complexity. It'd take far more than a readable post to discuss the spectrum of available devices, so I'll try to simplify enough to answer the question without embellishment. You need to discuss this with a qualified audiologist or otologist to get answers more directly applicable to your mother or any other specific patient.

 

Hearing aid size is a major factor - it's usually proportional to visibility, available gain, and sound quality at its highest output levels. You simply cannot get high gain with great fidelity from a tiny, in-the-canal aid (which is the initial choice of most people who are concerned more with concealing use of an aid than with better hearing & communication, e.g. my mother-in-law). Modern digital hearing aids are every bit as sophisticated as any other consumer electronics - they use complex DSP to shape gain to frequency-dependent sensitivity, abnormal dynamic range, etc and do an amazing job when well chosen and well set up for a given patient. But the gain necessary to restore serviceable hearing and the frequencies at which that gain is needed conspire to limit available maximum SPL at acceptable distortion levels, especially through the tiny transducers necessary to limit physical size of visible components.

 

Remember that the nature of the hearing loss is the basic determinant of the best possible restoration - if auditory discrimination is impaired, and/or the dynamic range is severely compressed by sensitivity loss at the bottom and abnormal growth of loudness at the top ("recruitment", which can also cause severe frequency distortion because hair cells adjacent to those tuned for the frequency being heard are sending the brain their own frequencies as well), even perfect amplification can actually make sound quality worse as gain increases. Many people simply get little or no benefit from hearing aids because of the nature of their hearing losses.

 

There are some excellent hearing aids that have incredible capabilities, e.g. wireless to the earpieces with a sophisticated controller (similar in size and appearance to a small smartphone) and a range of available accessories that includes a wireless streamer you can plug into an audio system. There are Bluetooth options, stationary remote microphones you can place in home & work settings etc. And the sound quality is excellent within the limitations of the transducers.

 

All this costs a lot of money - and in my experience, many of the patients who complain the most about their hearing aids are the ones who couldn't/wouldn't spend the added cost of the best possible aid for them. Sadly, most insurance provides little or no coverage for hearing aids, which leaves patients to bear the cost. But many hearing-impaired audiophiles can get very good sound quality from well fitted hearing aids, and even more can get serviceable SQ within the above limitations.

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My daughter has just got a new upgraded hearing aid, these have always been set up purely for listening to speech, but this new one has a music setting on it. I have not tried it yet to see if there is much of a difference between speech program and music program, but I would guess the speech bracket of frequencies is somewhat smaller than the one for music..??

 

Do you have such settings you could play with?

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Over on Audiogon some of us have been trying to help one of the members with hearing aid issues. You may want to have a look at some of the threads because there's a lot of information in them. His AG screen name is broadstone. If you do a search, you shouldn't have any trouble finding his threads.

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Has anyone noticed that while listening to music at reasonable sound pressure levels from usual listening position, that hearing aids are driven to distortion? I have noticed a "garbling" of especially female voices. A distortion that is subtle at first, often barely noticable, yet when perceived it makes listening unpleasant.

I seen it written that the Analog-Digital converters in many hearing aids are easily overloaded at the input side. One way to avoid this is to turn the music down, and turn the hearing aids up.

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I seen it written that the Analog-Digital converters in many hearing aids are easily overloaded at the input side. One way to avoid this is to turn the music down, and turn the hearing aids up.

 

Thanks for this last bit of practical advice. I will try this today and see how it goes.

mbain

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  • 3 weeks later...

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