Can't you just turn up the volume? • Hacker News Board

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

#101

Post by anigbrowl » Thu, Jan 08, 2015, 6:00 AM UTC

pistle wrote: post #73

anigbrowl wrote: post #29

What’s the solution? Multi-Band Compression (MBC), a technique that’s been used by the $6 billion hearing aid industry to solve this specific problem. An MBC uses intelligent design instead of a one-size-fits-all method. With the right data about your hearing pattern, it can mash the full sound into your range so that you get all the information you need. Audio engineer here. That is patently untrue. MBC is a super-u…

I was about to question everything until I read this. Thanks AE. My understanding of MBC is more like a crossover (or mix of low, bandpass, and highpass filters) network followed by compression per band within each section of the frequency range. Now, I want to go test out what it would be like to 'compress' frequencies. Something like a notch filter that shifts nearby frequencies around the target frequency away int…

If you're interested in frequency shifting, Harald Bode was the leading engineer in this area. You can read a gentle introduction here: and if you look around there are some VST plugins that emulate the Bode designs.

I haven't tried using this for precision stuff - over a small range it might well improve intelligibility at the expense of only minor distortion. I tend to reach for it when I want to give sounds an extra weird dimension, it sounds somewhat orthogonal to the normal harmonic distributions we're familiar with.

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

#102

Post by jimiwen » Thu, Jan 08, 2015, 6:01 AM UTC

rcfox wrote: post #18

a2kadet wrote: post #6

> "Sound expresses itself in three dimensions: time (seconds), volume (decibels) and frequency (Hertz)." Is anyone else as irked about the authors choice of the word dimensions as much as I am? I can't read past it. Wouldn't "factors" be a better fit?

Dimensions are variables that are independent of each other. They could be spatial dimensions like (x,y,z), or color dimensions like (red,green,blue).

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

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

#103

Post by LnxPrgr3 » Thu, Jan 08, 2015, 6:15 AM UTC

dlandis wrote: post #76

cheng1 wrote: post #72

Earlier quoted context omitted.

Hearing is an range. So they have reduced range on both side.

Hmm, I'm not sure you understand it any better than I do. The article says: > Well, if you get hearing damage at a specific frequency, you’ll start to lose sensitivity to the quiet sounds at this frequency. However, your sensitivity to loud sounds remains the same. If their sensitivity to loud sounds remained the same on the one hand, why would they be unable to tolerate certain sounds on the other hand. Seems contra…

I don't have an exact answer, but it's a common problem: http://en.wikipedia.org/wiki/Hyperacusis

Hearing is complex: you have the cochlea acting as both sensor and first pass signal processing. There's a muscle that acts as a built-in gain control that can cut sounds by about 20dB, partly so your own voice doesn't deafen you.

Hearing damage isn't just loss of sensitivity—apparently it can alter the shape of cochlear filters' response too, changing the way masking works. And I'd imagine the brain tries to compensate as hearing loss progresses, which could have interesting effects.

More info:

http://en.wikipedia.org/wiki/Auditory_masking http://en.wikipedia.org/wiki/Acoustic_reflex

Edit: Less related, but a similar phenomenon that happens to me: http://en.wikipedia.org/wiki/Misophonia. Hearing has odd failure modes.

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

#104

Post by cbhl » Thu, Jan 08, 2015, 6:25 AM UTC

zenocon wrote: post #100

curun1r wrote: post #66

Earlier quoted context omitted.

If you're looking for someone to blame, I highly recommend the guy that sued Apple because the iPod could be loud enough to cause hearing damage: http://www.ft.com/intl/cms/s/2/7bf03be0-94de-11da-9f39-00007... Apple eventually won and the case was dismissed, but the lower maximum value followed from that lawsuit.

wow, thanks for the info. lawyers - gah. still, no excuse for apple to limit the speakerphone...no one is at risk of hearing damage from a cell phone's speakerphone...you hear me apple?

until they put the speakerphone next to their ear, perhaps

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

#105

Post by wglb » Thu, Jan 08, 2015, 7:22 AM UTC

anigbrowl wrote: post #101

pistle wrote: post #73

Earlier quoted context omitted.

I was about to question everything until I read this. Thanks AE. My understanding of MBC is more like a crossover (or mix of low, bandpass, and highpass filters) network followed by compression per band within each section of the frequency range. Now, I want to go test out what it would be like to 'compress' frequencies. Something like a notch filter that shifts nearby frequencies around the target frequency away int…

If you're interested in frequency shifting, Harald Bode was the leading engineer in this area. You can read a gentle introduction here: and if you look around there are some VST plugins that emulate the Bode designs. I haven't tried using this for precision stuff - over a small range it might well improve intelligibility at the expense of only minor distortion. I tend to reach for it when I want to give sounds an ext…

Looks like you were going to paste a link but it didn't stic. . . .

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

#106

Post by adrianhoward » Thu, Jan 08, 2015, 7:40 AM UTC

thaumasiotes wrote: post #78

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…

> hearing aids sadly have a stigma attached to them It's probably worth distinguishing between two kinds of phenomena that might be described as carrying a stigma: - Something might lead other people to mock or otherwise denigrate you for exhibiting it. Being fat is a good example here; fat people get a lot of messaging from society that they're worse people for being fat. - Something might carry no real significance…

"I suspect that hearing aids are firmly within the second category, which means getting people to wear them "openly" should be doable."

You suspect wrongly. Having seen the attitudes to my father change when he wore one. Ranging from outright verbal abuse, to assumptions of stupidity & senility.

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

#107

Post by adrianhoward » Thu, Jan 08, 2015, 7:44 AM UTC

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…

"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."

This may also be a sign that the hearing aid wasn't fitted properly — or the shape of your father's ear has changed a bit since it was fitted. Poor fit makes it much more likely for this to happen (coz speaker and mike have a more open channel between 'em, and more ambient noise gets in so folk turn 'em up more). (My dad has similar problems until he got a new ear canal mould taken.)

It may also be a sign that you're dad's hearing loss has changed since the hearing aid was chosen and he needs it adjusting, or a different type.

Feedback is usually a sign that something needs fixing ;-)

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

#108

Post by sharpneli » Thu, Jan 08, 2015, 8:03 AM UTC

jimmaswell wrote: post #62

chias wrote: post #20

Earlier quoted context omitted.

Not really. A sound can be described by a one or more [time, volume, frequency] triples. I think the author's use of the word "dimensions" is perfectly suited.

Frequency is just periodic variation in volume so it doesn't really belong on that list as if it's a separate thing and not an emergent property

They are complementary. You can fully describe sound with either function of volume in time or complex amplitude (So normal amplitude + phase) in frequency. So you could just as easily say the volume is emergent property of the frequency.

Regardless it's an 1 dimensional function.

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

#109

Post by sharpneli » Thu, Jan 08, 2015, 8:06 AM UTC

jimiwen wrote: post #102

rcfox wrote: post #18

Earlier quoted context omitted.

Dimensions are variables that are independent of each other. They could be spatial dimensions like (x,y,z), or color dimensions like (red,green,blue).

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.

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

#110

Post by sandworm » Thu, Jan 08, 2015, 8:17 AM UTC

I wish people would put half the effort into prevention that this article puts into mitigation.

Work beside a machine humming at a particular frequency and you will loose that frequency even if the sound doesn't seem loud at the time. And simply jambing in a pair of earplugs doesn't make you immune. They have limits.