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Can't you just turn up the volume?

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Re: Can't you just turn up the volume?

#131

Post by TheOtherHobbes »

analog31 wrote: post #24
korethr wrote: post #15

This is nifty. My father has hearing loss and it's bad enough that not only does he use hearing aids, he is constantly turning them up until they feedback and start ringing. He doesn't hear the ringing, but I do, and I have some hearing damage of my own. And he wonders why his hearing aids go through batteries so fast. Their description of how hearing loss works gives me some ideas on how I can help my father manage…

It seems to me that a simple way to eliminate the feedback issue is to separate the microphone from the speaker. Hearing loss runs in my family, so I've watched my relatives struggle with hearing aids, and I've decided that when it's time for me: 1) I will build it myself and figure out the details, to hell with the audiologists and their racket. 2. I will carry the microphone and amplifier in my shirt pocket. No mor…

>It seems to me that a simple way to eliminate the feedback issue is to separate the microphone from the speaker.

That won't necessarily fix the problem. Feedback comes from bad electronic/DSP design. Physical mic/speaker positioning makes certain solutions harder, but in practical designs it's not (usually) the limiting factor.

Phones of all kinds, Skype, etc include adaptive echo/feedback cancellation already. It's a well-understood technology - adaptive cancellation has been used since the 1960s - although the fact that it exists is maybe not as well known as it could be.

(Protip - if Skype starts feeding back, you can often reset the adaptive filter by clapping once loudly.)

As for hearing aids - the first papers mentioning multiband compression date from the 1980s, so there's nothing new here, except maybe a lack of research.

My mother's hearing is pretty bad now, and I had to talk a professional audiologist through tuning her aids for maximum intelligibility. I couldn't fault his personal skills, but the consonant/vowel heuristic he'd learned in training was oversimplified and not giving good results.

He'd basically set up a phone curve filter, but in fact you need some low-mid for good intelligibility, especially on male voices. Once he dialed that back in everyone was happy.

Thing is, we needed three one hour sessions to get it in the ballpark. The real problem with aids isn't the technology, it's the fact that setting up a good prescription is really difficult and time-consuming - even more so for elderly people who may have problems describing what they're hearing.

Re: Can't you just turn up the volume?

#132

Post by josinalvo »

sharpneli wrote: post #109
jimiwen wrote: post #102

Earlier quoted context omitted.

does dimensions have to be orthogonal? different spaces can be transformed...

When talking about dimensionality they kind of have to be orthogonal. Because otherwise anything can be of arbitrarily large dimension, and thus the whole term loses meaning.

just to satisfy a possible curiosity: No

Your intuition is in the right direction, but not quite correct.

Think of a cartesian plot. Now, think of the Y axis "tilted" to the front. With those 2 "vectors" you can still describe the whole plane (for whatever "describe" means =P) If you tilt it so much the "Y" axis becomes paralel to the X axis, then you lost something.

Instead of "orthogonal" what you need is a mathematical property called independence (as in linearly independent) that basically means "not redundant to express a space"

Re: Can't you just turn up the volume?

#134

Post by raverbashing »

TheOtherHobbes wrote: post #131
analog31 wrote: post #24

Earlier quoted context omitted.

It seems to me that a simple way to eliminate the feedback issue is to separate the microphone from the speaker. Hearing loss runs in my family, so I've watched my relatives struggle with hearing aids, and I've decided that when it's time for me: 1) I will build it myself and figure out the details, to hell with the audiologists and their racket. 2. I will carry the microphone and amplifier in my shirt pocket. No mor…

>It seems to me that a simple way to eliminate the feedback issue is to separate the microphone from the speaker. That won't necessarily fix the problem. Feedback comes from bad electronic/DSP design. Physical mic/speaker positioning makes certain solutions harder, but in practical designs it's not (usually) the limiting factor. Phones of all kinds, Skype, etc include adaptive echo/feedback cancellation already. It's…

"Feedback comes from bad electronic/DSP design"

I see that you mention an adaptive filter, and that might be a good solution, however, you are limited by CPU power of the system and other constraints (like having to work continuously)

Bonus points if you tell me what are the poles and zeros of that system to avoid feedback.

Re: Can't you just turn up the volume?

#135

Post by ubercow13 »

korethr wrote: post #15

This is nifty. My father has hearing loss and it's bad enough that not only does he use hearing aids, he is constantly turning them up until they feedback and start ringing. He doesn't hear the ringing, but I do, and I have some hearing damage of my own. And he wonders why his hearing aids go through batteries so fast. Their description of how hearing loss works gives me some ideas on how I can help my father manage…

Did they change this after your comment?

>Dynamic range is the difference between the loudest and quietest sound you can hear.

Re: Can't you just turn up the volume?

#136

Post by rplst8 »

TheOtherHobbes wrote: post #131
analog31 wrote: post #24

Earlier quoted context omitted.

It seems to me that a simple way to eliminate the feedback issue is to separate the microphone from the speaker. Hearing loss runs in my family, so I've watched my relatives struggle with hearing aids, and I've decided that when it's time for me: 1) I will build it myself and figure out the details, to hell with the audiologists and their racket. 2. I will carry the microphone and amplifier in my shirt pocket. No mor…

>It seems to me that a simple way to eliminate the feedback issue is to separate the microphone from the speaker. That won't necessarily fix the problem. Feedback comes from bad electronic/DSP design. Physical mic/speaker positioning makes certain solutions harder, but in practical designs it's not (usually) the limiting factor. Phones of all kinds, Skype, etc include adaptive echo/feedback cancellation already. It's…

> Feedback comes from bad electronic/DSP design.

Absolutely wrong. Feedback comes from a loop gain of > 1. Period. Microphone and speaker proximity have everything to do with it.

Re: Can't you just turn up the volume?

#137

Post by jnbiche »

72deluxe wrote: post #116
randlet wrote: post #79

Earlier quoted context omitted.

"I don't see the elderly changing but our generation just might." I'm youngish (mid 30's) and recently had my hearing aids replaced and realized I had a strong preference to stick with fairly visible behind-the-ear units rather than something more "discrete". I want them to be visible so that people I'm interacting with will be more sympathetic about repeating themselves and may make an (possibly unconscious) effort…

That's very good reasoning. If a person with visual impairment walks around with a white stick, it's obvious and people normally cater for their needs. It shouldn't be any different with hearing. What a good point. I have an elderly friend who has suffered complete hearing loss in one ear after an infection and the other ear can only detect very very low frequencies, and he's constantly saying "PARDON?". It must be v…

> I wonder if they could put a pitch-shifting circuit in his hearing aid to shift sounds up/down so that they fall within his hearing range, whilst not shifting frequencies already in that range. That would help significantly, surely?

If you read the article, you'll see that's more or less what most modern hearing aids do, via a technique called multi-band compression.

Edit: Actually, here anigbrowl, an audio engineer, states that this is not how multi-band compression works: https://news.ycombinator.com/item?id=8854142

Assuming he is correct, my above statement may well be wrong.

Re: Can't you just turn up the volume?

#138

Post by chiph »

zenocon wrote: post #5

"Why can't I just turn up the volume on my iPhone?" is something I ask myself everyday and shake my fist toward Cupertino. Seriously, the gain on the phone is severely limited. Try listening to a voice call on speakerphone in even a moderately quiet environment with just a twee bit of ambient noise. It is maddening that I can't get any more volume out of this device without jailbreaking it.

I've had to call 911 to report a traffic accident, and can attest that the iPhone cannot be heard over adjacent traffic whizzing by. It just doesn't go loud enough. My current Nokia doesn't either. Since the phone knows you're making an emergency call, I don't see why the volume limiter can't be removed in that case.

Re: Can't you just turn up the volume?

#139

Post by jimktrains2 »

randlet wrote: post #79
ramLlama wrote: post #60

Earlier quoted context omitted.

A bigger issue with separating the microphone and amplifier is cosmetic: hearing aids sadly have a stigma attached to them and people are more likely to wear them if they are invisible. There is a reason why hearing aids are produced in hair colors. Also, I found that the best way to get rid of feedback was to get an ear mold rather than using an "open-fit" mold. This is a clear separation between the speaker and the…

"I don't see the elderly changing but our generation just might." I'm youngish (mid 30's) and recently had my hearing aids replaced and realized I had a strong preference to stick with fairly visible behind-the-ear units rather than something more "discrete". I want them to be visible so that people I'm interacting with will be more sympathetic about repeating themselves and may make an (possibly unconscious) effort…

> fairly visible behind-the-ear units

I've had hearing aids like that for almost a year, and "fairly visible" is a stretch; they're pretty blasé and don't stand out.

Re: Can't you just turn up the volume?

#140

Post by jimktrains2 »

raverbashing wrote: post #134
TheOtherHobbes wrote: post #131

Earlier quoted context omitted.

>It seems to me that a simple way to eliminate the feedback issue is to separate the microphone from the speaker. That won't necessarily fix the problem. Feedback comes from bad electronic/DSP design. Physical mic/speaker positioning makes certain solutions harder, but in practical designs it's not (usually) the limiting factor. Phones of all kinds, Skype, etc include adaptive echo/feedback cancellation already. It's…

"Feedback comes from bad electronic/DSP design" I see that you mention an adaptive filter, and that might be a good solution, however, you are limited by CPU power of the system and other constraints (like having to work continuously) Bonus points if you tell me what are the poles and zeros of that system to avoid feedback.

> other constraints (like having to work continuously)

I'd vote that next to no delay is a stronger constraint. With skype, you're already delayed, so adding a little processing isn't an issue. With a hearing aid, if there is too strong a delay it because off putting and, at times, dangerous.

But yeah, CPU and Power constraints in something about the size of the first joint of my pinky (including battery) are tight and very limiting.

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