Inexpensive hearing aid for vets

this minor battle, but there is a war still to be fought. I was in a gun magazine loading 80 pound projectiles and 35 pound gunpowder charges. There are many others who suffer hearing loss from flight line or engine room be sides those of us sentenced to the battle field.

pensive hearing aid. The target is zero cost, but I would be willing to pro duce at $40/ea. I am looking at various technologies.

ve some type of audio equalizer and an audio input to interface with other products and an output for ear buds or external speaker. Besides a hearing aid it could take the output from a transistor radio and do equalization a nd then output to ear buds or external speaker. The point is that it could make music sound good as well. It would be compatable with cell phone cha rger and perhaps USB or bluetooth as well

e of implementation. I am old time analog guy, but that isn't to say I wou ld be the person doing design. A few pots would probably be ok. A dsp mig ht be able to take hearing test data and program with a pc.

there are plenty of good people who would provide some pro bono work for t his cause.

her ideas as far as direction to make this a real product.

We had a thread on this not long ago, though with a circa $1 budget. If you can afford DSP you can do more than just amplify & boost the high end.

Clarity/fidelity & keeping latency low matter. If you can stomach the compromise, a shirt pocket type device is much cheap er to make & can get you good battery life & minimal run cost, which is a w hole problem area with miniature ear based aids. And Jim's old sliding clas s A is not current efficient by today's standards.

NT

< > with a pc.

Definitely go for DSP. I was doing this kind of thing around 25 years ago using the TMS320C50 family of 16-bit (32-bit accumulator) fixed point DSPs programmed in a mixture of assembler and C. There are now much smaller and cheaper and lower power devices available that would do the job.

Find out about the relative merits of finite- and infinite-impulse response filters in terms of stability, computational load and latency.

You may find it difficult to get anyone in the existing hearing aid fitting industry to help with interacting with users though, because they will not want to lose their huge markups.

Yes, you need to keep total latency below about 50ms, otherwise it will disturb the integration of sound with lipreading.

You might consider talking to some hearing aid manufacturers about this. However, you will probably not get a helpful response. Try anyway and see where it leads... Modern hearing aids are not expensive to manufacture and many use digital processing with high efficiency pulse width modulated output circuits.

There are standard protocols for communication between hearing aids and their programming systems.

Look up BCJ Moore's work on dual time constant AGC for use in hearing aids.

Expect to trip over regulatory issues relating to medical devices.

Have a look at "An introduction to the Psychology of Hearing" by Brian C J Moore, 6th edition for some useful background information.

Finally, think again about how you will get these devices configured for the people who need them at a reasonable cost. John

this minor battle, but there is a war still to be fought. I was in a gun magazine loading 80 pound projectiles and 35 pound gunpowder charges. There are many others who suffer hearing loss from flight line or engine room be sides those of us sentenced to the battle field.

pensive hearing aid. The target is zero cost, but I would be willing to pro duce at $40/ea. I am looking at various technologies.

ve some type of audio equalizer and an audio input to interface with other products and an output for ear buds or external speaker. Besides a hearing aid it could take the output from a transistor radio and do equalization a nd then output to ear buds or external speaker. The point is that it could make music sound good as well. It would be compatable with cell phone cha rger and perhaps USB or bluetooth as well

e of implementation. I am old time analog guy, but that isn't to say I wou ld be the person doing design. A few pots would probably be ok. A dsp mig ht be able to take hearing test data and program with a pc.

there are plenty of good people who would provide some pro bono work for t his cause.

her ideas as far as direction to make this a real product.

Please contact me by email. I may have some info for you.

Rick C.

If you have been on an artillery firing position for any length of time you actually need a pretty sophisticated hearing aid to stand any chance of it working well. My father was affected by deafness in later life - he put it down to being on anti aircraft firing position during WWII.

UK digital NHS deaf aids overtook what was available privately about a decade ago. You could pay even more to get something miniscule in ear but it you were prepared to live with over ear that was acoustically coupled into the ear then they were very good and improved in line with his decreasing hearing. Prior to that he had a private digital aid. He could lip read very well. Analogue simply couldn't hack it at all.

It makes no real sense to push the unit price too low when you need an acoustic chamber and a fair amount of test gear to fit the hearing aid to the patient. It is not a one size fits all solution any more.

DSP has been the way to go for more than a decade now. There must be fairly standard chipsets and implementations around. I expect these are rubbish but the NHS are remarkably good in terms of price performance.

Look to see what is available elsewhere before reinventing the wheel.

--
Regards, 
Martin Brown

50 ms corresponds to about 50 feet.

this will create a terrible echo

the latency needs to be

Correct, if you're unfortunate enough to have to pay out of pocket the audiologist appointments for digital hearing aid setup, regular adjustment, and maintenance are the major component of the cost

in this minor battle, but there is a war still to be fought. I was in a gu n magazine loading 80 pound projectiles and 35 pound gunpowder charges. The re are many others who suffer hearing loss from flight line or engine room besides those of us sentenced to the battle field.

expensive hearing aid. The target is zero cost, but I would be willing to p roduce at $40/ea. I am looking at various technologies.

have some type of audio equalizer and an audio input to interface with othe r products and an output for ear buds or external speaker. Besides a heari ng aid it could take the output from a transistor radio and do equalization and then output to ear buds or external speaker. The point is that it cou ld make music sound good as well. It would be compatable with cell phone c harger and perhaps USB or bluetooth as well

ype of implementation. I am old time analog guy, but that isn't to say I w ould be the person doing design. A few pots would probably be ok. A dsp m ight be able to take hearing test data and program with a pc.

ot there are plenty of good people who would provide some pro bono work for this cause.

other ideas as far as direction to make this a real product.

ou can afford DSP you can do more than just amplify & boost the high end.

aper to make & can get you good battery life & minimal run cost, which is a whole problem area with miniature ear based aids. And Jim's old sliding cl ass A is not current efficient by today's standards.

Thank you.

Yes a DSP would be able to implement an interactive hearing test to tune am plifier response. It could actually be tuned to be an anti-hearing aid, whi ch would allow my wife (who has perfect hearing) to understand what it is l ike to have my hearing. It would finally resolve the 'you're not paying at tention to me' argument. Shirt pocket is fine. Old timers who can't affor d a decent hearing aid or prefer not to deal with some of the garbage on Eb ay will have an alternative.

Thank you for input. There is a lot to mull over. I will include your input in the project folder - Magnum Opus auditu auxilium

All good input. Thank you. Yes, artillary damages those on both sides, an d in most cases years and years apart from each other. You know first hand that hearing loss is a real disability. You've heard your father say what a million times. I was first diagnosed with a notch at 4kHz 20 years ago. Now at 1khz it takes a nose dive. I am down 60db at 4kHz. Not so easy to develop an analog amplifier to undo the damage. I will tell you though tha t a simple equalizer does a fine job of making normal conversation possible and allowing music to sound good again.

I have done limited research and actually bought some off of Ebay. I do no t want to reinvent the wheel, but if it pans out I hope to be able to get m ore old timers into low cost devices that work well.

I expect there may be some government (DOD) grant money available. If

The main battle is to make speech intelligible which is quite different to making music sound good again. You will never get back your lost high frequencies and may accelerate your progression to deafness by trying.

Try to find those mass produced for other national health services where cosmetic appearance of the device is not the main priority. UK NHS units are a pretty good baseline for what is possible price performance wise

It is a bit of a puzzle to me that for normal high tech kit US price in

there is additional ripoff factor of 2-3x in the USA. Why is this?

BTW I thought US veterans got state provided healthcare so I am a bit puzzled that decent quality hearing aids are not included in the deal.

--
Regards, 
Martin Brown

Yes, at 50ms the effects will be noticeable. Much more than that and the integration of speech and lipreading is likely to be badly disrupted. Things get worse if the direct, unprocessed audio path is audible as well as the amplified audio. In that case there will be echo as you point out. Achieving a 5ms latency could be challenging, depending on the processing steps involved and the frequency responses that need to be achieved.

John

res

Medical is often not sold with the same competitive pressures as consumer i tems. Stores actually rent shelf space to vendors who then pay a share of the profit to the stores on top of the rent. This ends up being very compe titive. Hospitals and medical facilities often have very high mark up beca use of the total lack of competition in most markets. Frederick, MD with 1

00,000 population only has a single hearing aid facility to the best of my knowledge.

I met one gal in the business who talked about selling hearing aids for tho usands of dollars because they gave lifetime free service.

I know what goes into hearing aids and the unit itself could sell for the p rice of a blue tooth earpiece. There is no magic in them.

Rick C.

ll

I can't think why 5 ms would be hard to achieve, that's only 200 Hz. The p rocessing required depends on the sample rate and the extent of filtering. The sample rate will be no less than 8 kHz and likely much higher. Since each input sample has to be processed and output prior to the next input sa mple sub-millisecond processing delays should be possible. If you can't do this, the processing isn't fast enough to keep up with the data rate and y ou need a faster processor.

Am I missing something?

Rick C.

Make very sure you investigate the legality of selling it as a "hearing aid".

Perhaps you could call it a "PSAP Personal Sound Amplification Product", but beware of being lumped in with charlatans.

On Wednesday, 27 February 2019 08:55:28 UTC, snipped-for-privacy@gmail.com wrote :

processing required depends on the sample rate and the extent of filtering . The sample rate will be no less than 8 kHz and likely much higher. Sinc e each input sample has to be processed and output prior to the next input sample sub-millisecond processing delays should be possible. If you can't do this, the processing isn't fast enough to keep up with the data rate and you need a faster processor.

No, but there is usually more than just filtering. AGC is essential and this is sometimes multi-band and multi-time constant. That introduces some delay. Filtering delays depend a lot on whether any low-frequency equalisation is needed and what filter architecture is used. When filters need steep slopes it can be interesting to ensure that they are unconditionally stable when implemented as low-latency IIR designs, while stable and linear-phase FIR filters may need a lot of taps to get the desired response with an associated long delay. What I am really trying to say is that doing it properly is much more complicated than it might at first appear and involves some compromises, especially when power consumption is limited. Also, choosing the most appropriate settings for a particular person requires significant skill.

John

in this minor battle, but there is a war still to be fought. I was in a gu n magazine loading 80 pound projectiles and 35 pound gunpowder charges. The re are many others who suffer hearing loss from flight line or engine room besides those of us sentenced to the battle field.

expensive hearing aid. The target is zero cost, but I would be willing to p roduce at $40/ea. I am looking at various technologies.

have some type of audio equalizer and an audio input to interface with othe r products and an output for ear buds or external speaker. Besides a heari ng aid it could take the output from a transistor radio and do equalization and then output to ear buds or external speaker. The point is that it cou ld make music sound good as well. It would be compatable with cell phone c harger and perhaps USB or bluetooth as well

ype of implementation. I am old time analog guy, but that isn't to say I w ould be the person doing design. A few pots would probably be ok. A dsp m ight be able to take hearing test data and program with a pc.

ot there are plenty of good people who would provide some pro bono work for this cause.

other ideas as far as direction to make this a real product.

this may be the poster child for the example of over regulation. m

No. Absolutely not. Regulation is *absolutely* necessary.

And I say that as someone that is deaf, and whose father was very deaf, and whose mother is deaf.. Hence (a) I have personal experience (b) my family has personal experience (c) I do have a clue about the subject.

Is using a smart phone with a hearing enhancement program not an option? Is it cost or latency? Mikek

If you already have a smart phone, then cost is not an issue and there should be plenty of computational power available. I suspect that getting low latency could be a problem because the operating system probably wants to move blocks of samples between itself and the hearing enhancement app, so there will be buffering at input and output. High levels of amplification are likely to be a problem without properly fitted earmoulds to prevent feedback. Some people might well find such a solution useful, but probably not those with severe losses.

John