
Why has the hearing aid industry gone completely digital? - daddylonglegs
https://slate.com/technology/2019/09/hearing-aids-digital-analog-sound-music.html
======
hprotagonist
_Digital technology may offer advantages in its ability to tailor
amplification to a particular individual’s loss profile as well as the
availability of programmed settings for different social situations, plus
extra bells and whistles like Bluetooth and app-tracker options. What it
cannot do is faithfully reproduce natural sound in a way that is subjectively
satisfying and moving and true._

Oh buddy do i have a xiph rant for you. I am more or less entirely willing to
chalk this up to what I shall politely call “top-down effects”.

[https://people.xiph.org/~xiphmont/demo/neil-
young.html](https://people.xiph.org/~xiphmont/demo/neil-young.html)

Frequency tuning and rapid readjustment of it is the key feature of modern
hearing aids and we’re just barely scratching the surface of what we can and
should do.

Here’s why: presbycusis, or age-related hearing loss, has a cruel fact about
it. As the threshold of audibility rises for a particular frequency, the
threshold of pain lowers. Rather often, the reason people don’t use hearing
aids is that they create a situation in which you can hear but also every
sound is painful!

Precise digital control of per-frequency intensity amplification can make that
a lot less terrible. If it hurts to hear at 4khz, we can squelch that
frequency but boost the 100-400hz range and your speech audibility should
still get the boost you need to talk to your grandchildren. Throw a BLE
connection to a nice multicore GPU smartphone into the mix and we can start
offloading really complicated processing to the thing in your pocket.

~~~
TheSoftwareGuy
Can you really offload per-packet processing to a connected Bluetooth device
without injecting a frustrating amount of latency? Bluetooth isn’t known for
being a fast protocol

~~~
sansnomme
How do Bluetooth headphones compensate for the latency?

~~~
cjrp
In my experience, they don't; if I'm typing on an iPhone there's a noticeable
delay between me tapping a key and hearing the sound in my QC35s.

~~~
hprotagonist
That's not the bluetooth latency you're hearing, that's just how active noise
cancellation works.

QC35s buffer about 75ms worth of ambient noise and then phase-invert it and
play it back. This destructively interferes with the outside noise, and
cancels it. But you have to sample your environment on some time window to get
it to work, so when ANC is on, there's lag. This is also why ANC only works
well for slowly-varying noise like airplane drone, but can't handle impulsive
sounds like gunshots.

[https://en.wikipedia.org/wiki/Active_noise_control](https://en.wikipedia.org/wiki/Active_noise_control)

~~~
cjrp
Interesting, thank you!

------
KaiserPro
> What it cannot do is faithfully reproduce natural sound in a way that is
> subjectively satisfying and moving and true.

Gahhh. This just makes me want to cry.

Look, sonney-me-lad, you might want an analogue amp in your ear, that has a
terrible frequency response, is prone to feedback and will most likely destroy
what frequency range you have left, but lets not blame this as a technical
problem. (don't start me on battery life)

You like the "warm" sound of "analogue". Hand in hand with this claim, is that
somehow one can have the ability to tell digital recorded sound from analogue.
As an ex recording engineer, I can tell you, you're full of crap. I could[+]
make a very convincing "analogue" sound using a mackie D8b digital desk and 24
track digital recorder.

I can tell you now, that if I played a cd, housed it in a box that looked like
it had tube on it, then attached a record player, Piped it into a decent amp
with some NS-10s. It would sound great. To convince you of course I'd need to
clip off the top frequencies, (8k+) add some clicks and hiss (raise the
noisefloor) you'd then be espousing the wonders of its "warm analogue sound".

Why have digital hearing aids concurred the world? because they are better.
One can steer the microphones, they use less power, the frequency response is
trivially tuned to your hearing range, there are limiters in there to stop
damage, The speaker can be calibrated, as can the microphone.

you can add a directional handheld mic so you can point it at people so you
can hear them talking. You can add background noise reduction trivially.

All of this can't be done with frankly shitty analogue hearing aids.

Don't fuck up other people's lives with your nonsense.

~~~
jpindar
>clip off the top frequencies, (8k+) add some clicks and hiss (raise the
noisefloor) you'd then be espousing the wonders of its "warm analogue sound".

You know, you may have a product idea there. Not so much for hearing aids, but
as a standalone device.

------
localhost
My dad explained to me that his hearing loss is dominated by his inability to
zero in on conversations in a crowded room. That has made it so that he’s much
less willing to go out to socialize in restaurants, because that environment
creates a form of isolation brought on by his hearing loss. While his hearing
aids certainly do help, I would argue that they haven’t gone digital _enough_.

Being able to audibly isolate a speaker in a room full of other speakers would
be a boon for his case (and I would presume many others). Anyone on HN working
in this area?

~~~
snops
Speech enhancement (denoising/dereverb) and seperation is absolutely a hot
research topic, as it's needed for fields like voice assistants as well.
Unsurprisingly, the state of the art is variety of deep neural networks,
here's a good overview of recent developments [1]. Of course, many of these
are far from real time, but earlier techniques are used in some digital
hearing aids iirc. Apple have also released [2] some details of the system the
Homepod uses, along with audio samples.

A quite interesting further development of these is this paper [3] which uses
brain activity to determine which particular speaker the listener is trying to
hear, and then optimises that.

[1] [https://arxiv.org/abs/1708.07524](https://arxiv.org/abs/1708.07524) [2]
[https://machinelearning.apple.com/2018/12/03/optimizing-
siri...](https://machinelearning.apple.com/2018/12/03/optimizing-siri-on-
homepod-in-far-field-settings.html) [3]
[https://advances.sciencemag.org/content/5/5/eaav6134](https://advances.sciencemag.org/content/5/5/eaav6134)

~~~
sjg007
Deep neural networks should be able to do source separation.

~~~
hprotagonist
Imperfectly, but the results are at least passable.

------
rini17
I have profound hearing loss, wear hearing aids on both ears since early
childhood. I felt immediate palpable improvement when switching to digital
hearing aids. Only for listening to music I switch them to "analog-like" mode
(which, nevertheless still applies the 20-60dB equalizer and compressor I
need). Of course some people might have opposite experience, I am not trying
to invalidate anything.

The big picture is: sadly we don't really have any way to objectively measure
hearing quality and its improvement due to hearing aids. We can push buttons
whether we hear tones or not. We can count understood/misunderstood words. But
the results don't have clear relationship with real-life hearing situations.
For example, in my case, in silent room tinnitus appears which interferes with
testing. And sometimes I hear better, sometimes worse.

Unlike vision, it's very hard and time-consuming to test with any
repeatable/reproducible patterns, or to accurately explain to another person
problem with quality of the sound.

Also, the hearing aids market is very tightly controlled by oligopoly of
manufacturers and doctors. There is no way to self-adjust them. I'd very much
buy user-programmable BTE package capable of 80 dB gain which I need for some
frequencies. But there is plainly no such thing available without any strings
attached. I have played with jackd under Linux, too, don't remeber clearly but
it was problem to set the equalizer with 60dB differences.

~~~
noxxten
I'm also profoundly deaf, using two BTE hearing aids as well and your comment
is 100% what I'm frustrated with as well. My hearing aids are CONSTANTLY
"adjusting" noisy environments for me - Usually exactly when I don't want them
doing a damn thing. I'm very good friends with my audiologist, but it would
take hours upon hours in her office, fiddling with all the various controls
and options, to get things perfect. I want to be VERY clear too, it isn't a
problem of have too many controls, that's actually an amazing benefit... The
problem is that we can't reasonably expect audiologists to really spend the
hours upon hours of time making minute tweaks and adjustments to capture that
perfect hearing aid experience. It would just be SO much easier if after
wearing them for months and I suddenly noticed my "noisy environment"
adjustments were actually annoying, I could go in and make adjustments on my
own.

It's also infuriating how sub-par the accessories market is. I have a compilot
air 2 (bluetooth add-on) that lets my hearing aids connect to my phone, car,
computer, etc. It's great, but at $300 I really expected it to work for more
than a couple of hours... It also has to be clipped within 12 inches of BOTH
hearing aids? My phone communicates through bluetooth across the house to my
computer... Is there really no way around having to clip this dongle on the
neck of my shirt? It doesn't bother me now, but damn. People in meetings and
in public constantly think I'm recording them or something. Nevermind the
disgusted look I've gotten at a urinal. It's just... Not ideal.

~~~
SynasterBeiter
That's why you should self-fit. It's absolutely possible - check my comment
below for details.

------
dreamcompiler
> What [digital technology] cannot do is faithfully reproduce natural sound in
> a way that is subjectively satisfying and moving and true.

There is a one-word description of that sentence, and the word is "bullshit."
It might be the case that most digital hearing aids today do not reproduce
sound as faithfully as older analog ones. But it is always possible to build a
digital signal processing path that is _audibly indistinguishable_ from an
analog one in a double-blind test. It might cost more or require better
engineers than those who currently design hearing aids, but blaming the
problem on "digital technology" is utter nonsense.

------
Someone1234
To the question:

\- Smaller.

\- Improved battery life.

\- Better tailored to specific hearing loss (e.g. certain frequencies).

\- Telecoil compatible.

\- Improved Feedback Control. Better safety features.

The entire article could be boiled down to an argument that "analogue is
natural, digital is artificial." It compares digital hearing aids to MP3s. The
problem is, there's nothing inherently natural about the way analogue audio
works, and it can manipulate and alter the sound profile just like digital
(inc. compression/artifacting, particularly when space constrained/dealing
with cross-interference).

Just because a technology is older doesn't automatically make it more "pure."
If they argued for a way to configure a hearing aids/remove artificial
filtering, that's fine (I agree), but to suggest that digital and analogue
audio fundamentally work differently from a perceptual perspective isn't
really factual.

------
pjc50
There's two points here, one good one bad. The bad one everyone has already
spotted; the claim that digital is inherently worse.

The good point though is the one about the industry lacking participation from
people with hearing loss themselves. The "nothing about us without us"
argument. Plus a sub point about the US healthcare system being expensive and
not actually consumer friendly.

(Hearing aid wearer here who works for a digital audio company here! But I get
mine from the NHS, so I pay nothing and expect no choice. They work well but
not perfectly - the multiple sources problem is still big)

------
blattimwind
> Analog aids merely amplify existing sound—a more sophisticated version of an
> ear trumpet—such that there is no real interruption of the original acoustic
> wave.

That's just false and shows how little the author understands about audio
systems. The microphone and driver in a hearing aid (and their interaction
with the ear canal) alone will change the sound drastically, regardless of
whether the signal processing between the two is analog or digital.

~~~
willis936
In fairness the latency of an amplifier with no filtering is less than 10
microseconds. Coherency between the amplified and unamplified signal is
preserved. I’ve done some personal work on custom IEMs with ANC and the lowest
latency controller I could find was the teensy. Even in the fastest round trip
time you would be adding 5-10 ms of latency. Speed of sound / 16 kHz = 2 cm. A
whole cycle at 2cm. If you want coherent wavefronts then low latency is
essential. If the latency is fixed and less than the distance between the
speaker and the eardrum (very short) then you can do some DSP tricks to fix up
destructive interference.

------
js2
This just happens to be on NPR today: “Untreated Hearing Loss Linked To
Loneliness And Isolation For Seniors”

[https://www.npr.org/sections/health-
shots/2019/09/12/7602312...](https://www.npr.org/sections/health-
shots/2019/09/12/760231279/untreated-hearing-loss-linked-to-loneliness-and-
isolation-for-seniors)

------
knorker
Another neophobe "analog is better" opinion.

They're wrong. Vinyl is back because it's hipster and other reasons, and it's
in absolutely no way better.

In order for analog to be better either:

1) The (analog) filters on the hearing aids are bad. Not unique to digital.

2) You can hear more than 22KHz. I doubt it, mate. No offense but you're not
young anymore, so very unlikely among an already rare population.

3) Math is wrong. Fourier analysis shows that digital doesn't "approximate"
the frequencies of analog. It completely contains the exact same information.

------
raverbashing
It has gone digital because it's cheaper and allows for better custom hearing
curves. Because remember there's an underlying hearing issue already.

"It turns the world into mp3" digital quality is not necessarily bad, some
models might have issues, of course.

~~~
benoliver999
Sadly, years of 128kbps iTunes sales have ruined the idea of digital music for
a lot of people.

------
nickthegreek
Counterpoint: Adam Savage discussing his hearing loss and how awesome new
hearing aids are.

[https://www.youtube.com/watch?v=D-Ptuq85R8Y](https://www.youtube.com/watch?v=D-Ptuq85R8Y)

------
ianhowson
Interesting argument but I don't buy it.

\- Digital hearing aids are smaller, lower power and easier to configure than
analog hearing aids (think "fits in your ear canal" vs. "you wear the original
iPod on your belt")

\- The benefits of full-analog audio are contentious at best and almost
certainly imperceptible for people with hearing loss

If you want further convincing that A->D->A conversion is perfectly fine,
[https://xiph.org/video/vid1.shtml](https://xiph.org/video/vid1.shtml) is
excellent.

------
jjoonathan
> Analog aids merely amplify existing sound—a more sophisticated version of an
> ear trumpet—such that there is no real interruption of the original acoustic
> wave. Digital aids, by contrast, pick up the sound, process it into binary
> digital information, and then reproduce the sound as a new wave using a
> built-in digital-to-analog converter. Digital devices thus have to re-create
> the activity that our brains and ears co-evolved for eons to perform. It is
> hubris to think that a few decades of research and development might not
> fall short.

Why do writers so often accuse experts of "hubris" while arguing that their
own poorly informed opinion is superior to the well-informed opinion of said
experts?

That said, most digital systems don't make it easy (certainly not easy enough
to be relevant to a casual user) to obtain the many noise / filtering /
distortion effects you get with an analog setup, and that's a legitimate
complaint. While the audiophile scene is rife with placebo effects and woo,
I've long wondered if some UX lessons couldn't be salvaged. Could
hiss+pop+lowpass+distortion+hardware_pickiness settings be packaged into a
form that would make people willing to consume them in a digital context?

------
ses1984
Does the author actually have a reason why analog would possibly be better,
other than giving consumers choice?

Is the purpose of this article anything other than to generate clicks from
hipsters who will click on anything that paints digital in a negative light?

~~~
masklinn
> Does the author actually have a reason why analog would possibly be better,
> other than giving consumers choice?

Duh no. And this article does a disservice to itself, as it looks like there
could be a real issue of fidelity in the digital chain[0]. Bluetooth is known
to cause issues (lag, bandwidth variations, …), and the processing chain might
be problematic:

> the digital processor samples incoming sound at a rate far lower than that
> of an old CD player

I don't know if there's any truth to it, but it should certainly be
investigated and if true fixed. It might also be that the perceptual models
used in these hearing aids are not correct for, well, hearing aids.

[0] though some of the complaining could be a question of habit, the wearer's
old hearing aids had a coloration to which they'd gotten more and more used,
the different profile of the new ones is jarring even if it might be more
correct

~~~
ianhowson
CD sampling is 44.1kHz. 22.05kHz is used in plenty of HAs. I haven't seen
anything lower (but wouldn't be surprised to learn otherwise)

22kHz sampling isn't a problem in practice as:

\- HAs focus on speech comprehension, not music. Speech doesn't high much
content above 5kHz, so even 22kHz is double the Nyquist rate.

\- Music is perfectly enjoyable at 22kHz (but obviously better at 44kHz)

\- People getting hearing aids have hearing loss, and the majority of hearing
loss is in the high frequencies

~~~
trllamo
To add to this, most middle age adults can not hear above 15khz and threshold
is very high at 11khz, especially if they were exposed to high sound levels in
youth. Virtually no one can hear above 22khz.. if you ever hear people saying
they can it is most likely bs.

People often tell stories about playing a sound or being in a lab etc. they
_think_ they heard above 20khz, but mostly likely what happened is whatever
inevitable non-linearity exists in their playback chain acts as a mixer
creating frequencies well in the easily audible range.

------
patchtopic
I don't know about the technical tradeoffs in hearing aids, but the other
stuff in this article is breathtakingly ignorant.

------
btreecat
There are two great videos on why this author is wrong about digital sound.

[https://www.youtube.com/watch?v=Gd_mhBf_FJA](https://www.youtube.com/watch?v=Gd_mhBf_FJA)

[https://www.youtube.com/watch?v=pWjdWCePgvA](https://www.youtube.com/watch?v=pWjdWCePgvA)

------
arthev
Probably vanity?

[https://www.notechmagazine.com/2017/08/non-electric-
hearing-...](https://www.notechmagazine.com/2017/08/non-electric-hearing-aids-
outperform-modern-devices.html)

------
whamlastxmas
Also to add, the vast majority of the users use cell phones, and the ability
to pair your hearing aids to your phone is a big deal

------
o_p
Because digital is a completely superior choice?

------
mywacaday
Because marketing, need something new to sell. My mother in law has worn
hearing aids for years and was recently convinced to upgrade to the latest
greatest as she has to have her phone on speaker and has trouble
hearing/understanding when she can't see the person, eg, not in the same room
but shouting. S0 €5000 ($5500) later and still has phone on speaker and still
can't hear at a distance.

------
professorTuring
They went digital because "sound colors" doesn't exist.

Also: Niquist-Shannon.

