
A Better Way to Cancel Noise - prostoalex
http://nautil.us/blog/a-better-way-to-cancel-noise
======
avcdsuia
Here's an intro video [0] and here's the actual paper [1].

[0]:
[https://www.youtube.com/watch?v=VxcKkhmqXP0](https://www.youtube.com/watch?v=VxcKkhmqXP0)

[1]: [https://synrg.csl.illinois.edu/papers/mute-
sigcomm18.pdf](https://synrg.csl.illinois.edu/papers/mute-sigcomm18.pdf)

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raindropm
That aside, I found that construction earmuff is quite good for blocking sound
and gain focus — with just about 5% price of top noise canceling headphone in
the market. It took a bit getting used to though(and took quite some times to
'stretch' the earmuff in order to make it not clamp too tight to your head,
but it works quite well and very cheap alternative.

It looks derpy though so I can't wear it in the office — where I want to use
it the most. :(

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peatmoss
You can sometimes pair a decent in-ear pair of headphones with shooting /
construction earmuffs, depending on the clearances. That’s the best of both
worlds IMO. Also, don’t worry about looking derpy; I give you blanket
permission to not care :-)

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nordsieck
A great alternative to your setup is a set of plugfones [0].

They're an earbud that's an earplug first and a speaker second, which means
they have an NRR rating and are generally pretty good earplugs.

[0] [https://www.plugfones.com/](https://www.plugfones.com/)

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ketralnis
I've tried these for motorcycling and have found that the foam style is
_enormous_ and won't fit in my normal-sized ears :(

(They also have a baffled style that won't stay put while I put on my helmet
but of course that won't affect you in an office)

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Ricardus
The MUTE solution sounds interesting, and is certainly worth some research,
but I see it having some problems. One obvious one is that the receiver might
stay in that guy's window, and you might be in the apartment, say 15 feet
away, so within that distance you can overcome the latency issue that was
mentioned (because radio waves travel faster than sound waves) but the fact
remains you're 15 feet away from the microphone in the receiver, and by the
time the sound reaches you, it has changed dramatically. It has reflected off
of 1000 surfaces by then and looks a lot less like it did at the receiver. So
creating a waveform that's 180 degrees out of phase would be a gigantic
challenge. I suppose you could do some work with Impulse Responses to solve
this. You could take an IR of the room where the listener is and probably
account for a lot of the changes and use some DSP to modify the waveform to
make it more correct. But then if you move somewhere else in the room,
everything changes and needs to be recalculated. Interesting idea though.

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randyt
The solution is to use adaptive filtering.

~~~
Ricardus
The farther the microphone gets from your ears the harder the problem gets to
solve. It's an interesting idea, but I suspect this won't see prime time in
any meaningful way.

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tedunangst
The description was rather vague, but seemingly equivalent to a pair of bose
headphones with the microphone extended out a few feet in the direction of
noise to allow more time to calculate the antiwave?

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gnicholas
Yeah, except of course there are reflections from all over the place, so just
extending it out in one direction wouldn't solve the problem. I think this is
what the reference to IOT was all about — if you had a few sensors in the
room, then you could do a better job of this.

I've wondered if a HomePod or two could do this — I understand they are
currently able to discern a very quiet "hey Siri" (even when playing loud
music), due to their spatial awareness. Of course, the HomePod would also need
to know where the listener(s) is located in order to cancel the noise.

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anonu
I live in NYC and I'm a longtime user of the Bose QC20s. They are probably the
best commercial noise cancellation devices. I even sleep with them. The
article promises some significant leaps in the technology. No doubt as
processing gets faster and smaller we'll have even smarter noise cancellation.
Looking forward to that...

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therein
> I even sleep with them

I used to do that with my QC15 first and then after it broke twice, with my
QC25 replacement. Sleeping with them on is really tough on them, though. After
the third replacement device, I decided I couldn't keep on doing it no matter
how much I actually enjoyed putting it on at night and hear that soft static.
The slight pressure actually felt pleasant.

Quitting using them for sleep was hard, though. I certainly felt the urge to
buy a new pair but now I sleep with a pillow on my head if I'm sleeping on my
side, or a puffier pillow put sideways under my head positioned in a way that
it will cover my ears if I am sleeping on my back. It is no perfect
replacement but I think the reason why I do that is because I am still seeking
that QC20 feel.

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kmonsen
They make a pair for sleeping with if what you want is white noise:
[https://www.google.com/search?q=bose+sleepbuds](https://www.google.com/search?q=bose+sleepbuds)

~~~
therein
It isn't exactly white noise that I am looking for. It is the residual
waveform QC25 has after it has done its best effort at noise cancellation.

With that being said, after looking at here [0] it actually looks pretty
promising although it seems to not have active noise cancellation.

[0]
[https://www.bose.com/en_us/products/wellness/noise_masking_s...](https://www.bose.com/en_us/products/wellness/noise_masking_sleepbuds/noise-
masking-sleepbuds.html)

~~~
zone411
I'm assuming you've tried basic earplugs with white noise generator at full
power? When I used them to block out building construction noise, they worked
well. Maybe even too well - I was wondering if I'd wake up if a fire alarm
went off. Active noise cancellation doesn't work well with noises like
ambulance sirens.

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kardos
Someone needs to invent an expanding foam that you spray in your ear and it
solidifies in a few moments to form a perfect seal. It needs to somehow not go
too deep and cause problems, and be easy to pull out and discard afterwards,
ie, you can sell it forever like razor blades. Bonus points if it's
biodegradable and can go in the compost.

~~~
mikhailfranco
Why would you want to take it out?

Perfect at work.

Perfect at the bar on the way home, to protect against the _pub bore_.

Perfect at home for the wife & babies, and a few years later ...

Perfect immunity from the acoustically-lethal menopausal wife & teens combo.

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kachurovskiy
I have some of the best noise cancelling headphones (Sony MDR-1000X) and the
thing few people realize is that active noise cancellation actually increases
perceived pressure on your ear. For me it's like being underwater. I'm only
really using them while flying.

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jmiserez
I had both the MDR-1000XM2 and the Bose QC25, and the QC25 actually feel more
like underpressure. I don’t think feeling overpressure is inherent to noise
cancelling. I suggest you try out the QC25/35 in a store and see if they feel
different to your ears.

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bajsejohannes
I have the QC35 and it feels like overpressure to me. Might be an individual
thing.

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Izmaki
To me canceling headphones are only useful if I don't have a migraine. If I do
have one and I try to use noise cancelling headphones, it feels like my head
is spinning in circles and is about to blow up. Removing sound will for me
always be better than combating noise.

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p1mrx
It seems like this would require an array of microphones, plus knowledge of
the user's location, mushed together into a model of the environment. Like
MIMO for sound.

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keyrob32
Completely agree. With only one microphone placed somewhere around the cubicle
it would not be able to detect the direction the sound is coming from. In
worst case the sound wave reach you before the microphone... Also in order to
create the perfect anti wave the distance between you and the microphone has
to be known really well. I think this is actually one of the huge advantages
of wearable noise canceling headphones.

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puranjay
If this device truly did exist in the marketplace, I would pay a very good
price for it.

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twtw
i dream of cars with an array of speakers around the wheels to cancel the road
noise.

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mikhailfranco
The multi-channel case of using many anti-noise generators is much more
complex than a simple single-channel.

I once proved a nice theorem about the multi-channel case, using Lagrangian
multipliers and the theory of _Gershgorin disks_ , which are what you get if
someone upsets a Tower of Hanoi game all over your complex plane:

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

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t0mbstone
So... There's a concept, but no actual product. Got it.

~~~
ape4
But a cool idea

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therein
I'm with the GP on this.

It isn't that novel either because of a failed product trying a similar
concept:

[https://www.youtube.com/watch?v=MCW5HUkrr-o](https://www.youtube.com/watch?v=MCW5HUkrr-o)

~~~
randyt
No, these two are very different. The one in your YouTube link is absolutely a
scam, because no one can do "remote" noise cancellation without feedback
signals around human ears. But this work makes very much sense to me (as an
audio engineer).

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tamersalama
I hate white noise and It bugs me a lot in current office settings (theory is
that my brain is trying to make sense of what's thrown at it).

Isn't anti-noise signal, in itself, a noise? Whether or not it perfectly
matches the noise signal or lags behind. Wouldn't that be more patterns that
the brain would try to make sense of.

~~~
anmorgan
It would not be more signal.

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

The goal of noise canceling is to fully use destructive wave interference to
create a 0 amplitude "signal", which is no signal at all.

