
Scientists say you can cancel the noise but keep your window open - jrwan
https://www.nytimes.com/2020/07/11/science/windows-street-noise.html
======
jacquesm
Very timely. So, after boycotting a certain manufacturer for more than a
decade on account of their root kit debacle I finally relented and spent some
money on a noise cancelling headphone. It works pretty good, the tech has
matured and the difference between NC on and off is remarkable. Even a
neighbour mowing their lawn or using a chainsaw disappears to the point that I
can focus on playing an instrument or writing a piece of code or text.

This was a key element for me in overcoming my insomnia, I used to stay awake
at night because it was finally quiet enough that I could concentrate. After
identifying that as a key part of the problem noise reduction became a focal
point. It has created a new problem: the headphones are so good at this that
it is very easy to creep up on me and scare the bejezus out of me when I don't
receive any other clue such as a changing shadow or something like that. I'll
have to figure out some kind of early warning system for approaching people.

Whoever cracks this particular nut without headphones and manages to create a
bubble of 2 cubic meters or so that is silent from outside interference will
make a lot of money. The article lists one entrant that seems to be a move in
the right direction but it does not look like that particular version will be
ready for prime time in the near future.

My 'ideal' soundsucker (sonic black hole) is a ceiling mounted device that
projects a cone of silence. One possible way in which it could work is by
using a phased array of speakers to 'fake' a larger one. But that ideal will
likely never be reached due to limitations in physics, imagine the problem as
applied to a wavy surface of water: create a wave pattern that cancels out the
wavy surface in one circular area without touching the water directly.

Edit: Another - unexpected - benefit is that all the fan noise and other
ambient noise in the room I'm in (which I normally don't even notice) also
drops by a very large factor with NC enabled.

~~~
mamcx
> spent some money on a noise cancelling headphone Which one? I also facing a
> noise issue with some people that move closer, and getting crazy...

~~~
sqlacid
I'm not OP, but I'm sure he's talking Sony, I did a similar boycott (rootkit
on Sony music CD's), but recently bought WH-1000XM3 and the NC is phenomenal,
battery life is very good; very comfortable and lightweight; not sure I could
sleep with them on though.

~~~
mgkimsal
Can't say about the Sony, but you can't sleep in Bose QC20. Well... you _can_
, and they were pretty comfortable, but they'll very likely break pretty
quickly. I went through several pair until I finally twigged that sleeping in
them was probably the root cause. Have had fewer problems with the QC20 since
not sleeping with them in.

~~~
TylerE
Really, for sleeping just get a good set of passive earmuffs like shooters
use. Cost about $20 and will provide 25-30db of real noise reduction (and
unlike active NC will also work on non-periodic sounds like sirens or revving
car engines). Can double up with foam earplugs too for even more blockage.

~~~
dahfizz
Where do you people live that you need ear muffs capable of deafening gun
shots just to sleep??

~~~
TylerE
Anywhere noisy? When used around guns that don't (nearly) deafen them, just
bring them down to non-damage causing levels.

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ed
A low tech alternative mentioned in the paper is the Plenum Window. Imagine
sliding glass shower doors, but with a bigger gap between panes for airflow.
It also claims 10dB reduction, and doesn’t need a computer :)

Also from the paper: typical noise cancellation systems create local dead
zones of radius ~1/10th the wavelength of blocked sound. E.g., you can block a
1KHz wave within 3.4cm of an error correcting microphone. Good enough for
noise canceling headphones but not a whole room.

This work builds on an earlier finding that you can treat the window itself as
a point source. Noise cancellation at its source is much more effective, so
this way they’re able to create a dead zone the size of your apartment.

~~~
cheerlessbog
That's with one microphone and presumably a single speaker. I wonder how well
one could do with several microphones around the room and several speakers,
with their relative positions known accurately and some computing power to
generate the best possible reverse sound distribution.

~~~
ed
You’d need a lot of speakers (one every 6.8cm) to get the same coverage with
an array inside the room.

~~~
TheOtherHobbes
And it's a _much_ harder problem, because antiphase sound from multiple
sources will interfere with itself and probably also interact with room
resonances, potentially making the problem worse in some locations.

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davidhyde
Technology for noise cancelling headphones is fairly straight forward. You put
a mic near the entrance of the ear and then reverse the wave. The ear is
basically a one dimensional sensor in that configuration. Now, take the
headphones away then think about what you have to do to cancel noise. You have
this two dimensional window in your home that lets through three dimensional
sound waves. The best that you can manage is a two dimensional speaker array
which is what you see there attempting to create some sort of sound hologram.
It’s insanely complex and anyone who thinks that a company who makes good
noise cancelling earphones would therefore be capable getting technology like
this to work is just very naive. It’s another magic leap. A whole bunch of
people who think they are not buying into snake oil when they really are.

~~~
coldtea
> _Now, take the headphones away then think about what you have to do to
> cancel noise. You have this two dimensional window in your home that lets
> through three dimensional sound waves. The best that you can manage is a two
> dimensional speaker array which is what you see there attempting to create
> some sort of sound hologram._

First, what you be the problem of creating a three dimension speaker array?
Sounds totally feasible...

Second, is that really "the best" that we can do? I've read about a mesh of
special design that you can put on your window that still lets you see outside
and lets air go through, but cancels certain movement/frequencies, cutting off
noise.

~~~
davidhyde
You’re right, I should have been more explicit. Passive noise cancellation is
far superior for a window. I was trying to point out that active noise
cancellation is not feasible (not impossible though) because of the extra
dimensions and that the engineering behind active noise cancellation
headphones is not the same as what it would take to cover a whole window. By
several orders of magnitude.

Honestly, people should just drill an extra hole in their walls, add a quiet
fan and put a series of passive sound plates and other known geometry to
cancel the sound. Or pipe fresh air from the roof.

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rdiddly
Creating a negative copy of the ambient noise - won't that increase the noise
for everyone else? Say you live across the street from a neighbor who has this
device. Street noise happens. It reaches you, and your neighbor's cancellation
device, at roughly the same time. The device creates the cancellation wave,
timed perfectly for the neighbor. That wave also propagates back toward you,
and you hear it as an echo, with a delay corresponding to the width of the
street.

~~~
ed
Sound decays exponentially as a function of distance, so speakers close to you
don't need to be loud. Also most speakers are also fairly directional, so i'd
expect any extra energy to be absorbed by the room (as heat).

Edit: more importantly these are destructive waves, so if anything you’d
actually reduce reflections back out into the world.

~~~
hwillis
quadratically (proportional to x^2, the surface of an expanding sphere) as
opposed to cubically (x^3, the volume of an expanding sphere) or exponentially
(2^x, objects that multiply over time)

~~~
ed
ah yeah, thanks!

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odiroot
This is actually very very important in Singapore. There's multiple highways
(sic!) going through the middle of the city. Even on higher floors (say 15 -
20) the constant noise is unbearable if you live on top of one.

I didn't notice many sound isolating walls there either. Guess people who were
born there get used to it.

~~~
lgas
Out of curiosity, what's the idea behind including a "sic" parenthetical in an
original unquoted piece of writing?

~~~
wizzwizz4
"Sic" means "that's not a mistake". When quoting, it often means "I didn't
make the mistake, I faithfully copied somebody else's" but when writing your
own stuff, it means "I didn't make a mistake; I meant to write that".

~~~
lgas
Ok, gotcha. I'm familiar with it (in the "sic erat scriptum" sense) for other
people's writing but I've never seen it used in an original writing like that.

Not sure I get it here either, since most cities I can think of have multiple
highways going through them, but thanks for the clarification. Always glad to
expand my understanding of language.

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fxtentacle
When I was living in Singapore, all the rich people were on the higher floors
where you don't hear the road anyway. Or they had their own villa with garden.
Back then, noise pollution was considered mostly a poor people issue. Glad to
see that they are now finally getting an upgrade, too :)

~~~
Gigablah
I live on one of the higher floors (30+) and you can definitely still hear the
road from here. Granted, I'm next to a highway...

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calf
The reverse, a cancelling field for outgoing noise, would be great for
practicing music instruments, or guest parties, times when you don't want to
disturb neighbors (or roommates). Do the scientists discuss this?

~~~
jacquesm
For many instruments the solution is simple: practice on an electronic
version. This obviously does not hold for all instruments and not all kinds of
practice but it can have a big impact. It has an additional bonus too, you can
put on a headphone and cut the outside world off as well so it works in both
directions.

~~~
calf
I play classical piano, it's really just not the same hehe. At least, the
consumer technology is not quite yet there.

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atum47
I'm actually, right now, spending about 6k trying to sound proof my work area.
If I ware a billionaire, I'd give these people millions of dollars as
investment. Or to another team that could figure it out how to turn your
hearing on/off on command.

~~~
molszanski
Maybe in the long run we could decentralize our habitat and eliminate the
lions share of the problem

~~~
atum47
tell me about it, I'm working and saving some money so the future me can get a
cabin in the woods somewhere. or on the ice, if I'm doing really well.

~~~
pbhjpbhj
What's a "cabin on the ice"?

~~~
atum47
[https://www.instagram.com/p/B5x5YEVp_B2/?igshid=dn2n66w70sj1](https://www.instagram.com/p/B5x5YEVp_B2/?igshid=dn2n66w70sj1)

~~~
atum47
yeah, this was probably on my copy/paste from a previous conversation. sorry,
this is not a cabin on the ice

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oh_sigh
no paywall: [http://archive.is/zo83N](http://archive.is/zo83N)

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enitihas
This will be revolutionary if it is deployable at scale. One thing I have
learnt over the years is to avoid apartments which have any windows towards
the road.

~~~
hwillis
With certain windows, for certain sounds, you can put actuators on the window
itself. They vibrate the glass as a speaker. Unfortunately it is very tricky-
the resonant frequency of glass panes is far lower than sound, so its very
hard to make the glass all move together. Instead it prefers to take on wavy
bends, which can even create their own noise.

One neat idea is electrostatic speakers! They're one of the more exotic
speaker types, but have unparalleled quality at low volumes. However they are
prone to distortion as volume increases and require high (100+) voltage
supplies. They can be dangerous and fragile.

The idea is you stretch a mylar film very tightly into a rectangle, and then
sandwich it between two metal meshes, with an air gap. By putting voltage on
the meshes, static electricity pulls the mylar forward and back while keeping
it almost perfectly flat.

You can put meshes (or ITO films) inside a double pane window to create a very
even force over the whole window, making it an excellent transducer. It
requires far higher voltages to move glass, though. Putting mylar in between
the panes doesnt work (you need some free space to create proper cancellation-
oversimplifying) and putting mylar on the outside is dangerous. Tricky
problem.

~~~
eternalban
You mentioned danger twice. Can expand on this aspect of the tech?

~~~
hwillis
By the nature of the device the meshes need to be fairly exposed. They can be
enameled so as not to shock you, but only barely. Any scratch, rubbing, or
other wear can expose bare metal at >1 kV. That is a major fire risk; any
spark is presumed deadly in electrical engineering. Dust accumulates
everywhere, and you'd be amazed how much people mistreat electronics. Leaves,
dirty laundry and dust may as well be tinder.

The even bigger concern is mostly that a moderately loud speaker system
(>50-150 watts) can electrocute you. I mean that literally, as the portmanteau
of electricity and execution. 1 kV is easily enough to put electricity through
your heart; 50 milliamps would be lethal. 50 mA at 1 kV is only 50 watts, less
than a laptop charger. A big set of electrostatic speakers can just stop your
heart if you're very unlucky.

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gliese1337
Important distinction: this is an epistemic "can", not a deontic "can".

In other words, they are saying that it is possible to keep your windows open
if you want to and still not let noise in--not that you are permitted to
cancel the noise, but must keep your windows open anyway.

I had initially thought this would be something about indoor CO2 buildup or
something, but no.

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blahblahblogger
Can the outside world hear in though?

People may forget themselves and lose sense of perspective. I have a bipolar
condition where sometimes I'll pace my apartment and yell about anything and
everything, if I lived in one of these places I imagine it'd exacerbate things
and bother the neighbors too.

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lostlogin
> Dr. Lam explained that “in places like Singapore, we want to keep the
> windows open as much as possible”

I haven’t spent a lot of time in Singapore but the time I spent there had
visibility of about 50m from the burning of scrub/jungle in Malaysia and the
air quality was abysmal.

~~~
rorykoehler
It’s unusual for there to be haze. When there odds have it’s awful but it only
happened twice, once bad and over mild, in the 4 years I lived there.

~~~
lostlogin
Thanks, things must have improved as its 10+ years since I was there and it
didn't seem an unusual event then.

~~~
rorykoehler
They started suing the companies responsible after the 2014 (?) Indonesian
forest fires. Seems to have been effective.

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lambdatronics
Here's a low-tech approach: fill the window with staggered plastic straws. You
don't get much of a view, however, and the airflow would be impeded.

[https://www.researchgate.net/profile/Martin_Tenpierik/public...](https://www.researchgate.net/profile/Martin_Tenpierik/publication/336700023_Drinking_Straws_as_a_Broadband_Sound_Absorber/links/5dadc85ba6fdccc99d92851a/Drinking-
Straws-as-a-Broadband-Sound-Absorber.pdf)

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jrussino
I’ve lived in a few apartments that were situated along busy roads. Something
like this would be nice, but I’m hopeful that we’ll someday get to a point
where (almost) all of the vehicles on our roads will be electric. Has anybody
worked out how much of a noise reduction we can expect from that?

~~~
controversy
EVs will require a mind change. I have a hybrid. I drive it in St Augustine
FL, America’s oldest city. As such the roads in the historic district are
narrow.

When I come to an intersection I have to be especially conscientious because
pedestrians are use to engine noise bouncing down the road ahead of the car.
People have walked out in front of me unaware of my existence. I normally
mouth, “Surprise, motha fucka” or “I’m Batman” when that happens.

~~~
johnny_reilly
Are you Batman?

~~~
pfraze
That’s a controversy

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snarfy
I tried making something like this for closed windows out of a pair of broken
NC headphones and some surface vibration speakers stuck to the window. It
didn't work very well.

This did get me interested though and am curious of what software libraries
and solutions are out there for noise canceling. I would very much like to
hook a mic and speakers up to a raspberry pi and get some of the road noise
reduced. I'm not sure where to start with software though. I know the basic
premise is invert the signal coming from the mic and output that. That's not
exactly state-of-the-art though.

~~~
sjg007
Interesting. I always thought that the window would make a good speaker. So..
what issues did you run into? You say it didn't work very well? Did you
account for the delay?

It sounds like this should work...

~~~
snarfy
I took the NC headphones apart. I added wires to the mic used for noise
cancelling and hung it out the window, closing the window around the wires. I
added wires to the headphone speakers and connected them to a small amplifier
that was hooked up to the surface vibration speakers. It took about an hour to
do.

When it was on and NC was engaged, it was actually louder in the room when a
car drove by. The counter noise was adding, not subtracting.

It's was a quick and dirty hack. I assumed the physics and algorithm they use
requires the mic to be closer to the speakers and gave up. It would have been
pointless to try to modify it further. That's why I was hoping there is a
software solution that I could actually have a chance of modifying and e.g.
fix the delay if that is the problem. Maybe even a ML solution.

~~~
sjg007
Yeah should be possible. I am thinking of working on this. Not sure if an ML
solution is necessary but it would be cool and would work.

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klyrs
This invention seems like something straight out of a Sharper Image catalog.
Neat concept, but needs a few generations of miniaturization before I'd
remotely consider it.

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anonmidniteshpr
I don't see how it's possible to win ANC against loud, booming, tiny
reproductive bits car stereos driving by wannabe cholos because the speaker
size to produce phase-canceling mirror sound would have to be 10-12" / 25-30cm
and placed probably on 3 sides minimum... say 12 speakers or 24 for all 6
sides. And the SPL of the ANC would need to be sized proportional to the most
powerful car stereo one wished to block.

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eejjjj82
For anyone interested in building this DIY on a smaller scale I highly
recommend this Tech Ingredients youtube channel's video:

[https://www.youtube.com/watch?v=--c0tiIZG6o](https://www.youtube.com/watch?v=--c0tiIZG6o)

This is by far the nerdiest channel I subscribe to and I LOVE it.

------
Fice
Could this problem be solved with an adequate ventilation system, so there
will be no need to keep windows open?

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Faaak
I'm always dumbfounded when I see that noise emissions are still not taken
seriously and not enforced.

I live near a freeway and the cars don't bother me that much (I'm far away
that they sound like white noise). But the motorbikes, however, are the works.

Some of them don't make that much noise, but the outliers make you go crazy.
It's a shame really

~~~
techsupporter
> but the outliers make you go crazy

Agreed, so very much. I live across the way from an old-age care home and,
based on stereotypes, you'd figure that would be quiet living. Not so much.
Their landscaping crew gets out with leaf blowers every day, they have a
weekly generator run-up test that lasts for half an hour and pulses with a
deep bass, and every few hours on every nice day they pump out the best hits
from the 1940s and 1950s on their outdoor patio.

Almost all of these are louder than the city's rules permit but code
enforcement has told me that because both buildings face each other over a
privately-owned parcel (one of these "privately owned public spaces"), the
noise transmission rules do not apply.

I found this out after I called the care home, twice, to ask if they could
maybe turn down the music or do the generator test later in the day (when more
people are out and it would be drowned out by other ambient noise) only to be
told, politely, to bugger off.

I like living in a city and am not going to move--it's not _that_ annoying,
compared to benefits I get in return--but sometimes I wish the commons weren't
so tragedy.

~~~
shados
This is something that drives me banana. The answer you'll get is always
"Well, cities are noisy, deal with it or live in the suburb _.

But the thing is they don't have to be. Sure, you have to expect people
talking, cars going through, people mowing the grass, the occasional honking.
But even in the middle of Manhattan, the only noise that will wake you up in
the morning are people being assholes or breaking rules. Special construction
permits that have no business being issued (eg: jackhammers in the middle of
the night), people screaming (why?), harleys motorcycles (why is that legal?),
neighbors blasting music (you can hear it just fine, can you lower it a bit?),
musicians in apartments (can't you use an electronic drum to practice?).

Everything's avoidable. People are just inconsiderate, and/or the problem
isn't taken seriously. But no, it's not inherent to living in a dense area,
unless you're talking about "being surrounded by assholes" being inherent to
cities. Then yeah.

_suburbs aren't really a solution because people can be assholes everywhere.
But even if they weren't, current pushes to get rid of restrictive zoning
means you won't be safe in a suburb for much longer anyway. We need solutions
for noise in densely populated areas because we're not going to be able to
avoid it long terms. The solutions all exist, they just need to be implemented
and enforced.

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rossmohax
Is it possible to solve it mechanically? Like airtight, soundproof windows for
light and S shaped duct padded with acoustic foam for ventilation?

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sjg007
The other solution here is to put the speakers on the window frame, then you
can do some projection etc...

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djhaskin987
If you're going to put up a wall up on your websites, make sure they load
right away instead of loading the whole article before the paywall gets
loaded.

I was able to read this entire article despite its pay wall by screenshotting
the article before the pay wall came up. I had to reload the page, screenshot
several times, and time it right but I was able to read the whole article.

~~~
ip_addr
On sites like these i've started disabling javascript.

~~~
wizzwizz4
Private window, enable JavaScript, bypass GDPR banner, disable JavaScript.
(Though I'm boycotting NYT until the risk to Scott Alexander has passed.)

