Scientists say you can cancel the noise but keep your window open

Poking around I couldn't find them, but there are rather a lot of tiny fish-eye mirrors being sold to affix to the top or corner of a car rear view mirror (so-called blindspot mirrors). Those should be in roughly the correct size classification.

Why not just put a mirror on your desk?

You can tell roughly how far away a sound source is by measuring the curvature of the wavefront, since sound radiates out in a sphere. The farther away you are, the lower the parallax between two sensors.

If you have sensors with 20 cm separation (each ear) then you would need a minimum sample rate of 34.3 kHz to easily correlate sounds within 2 m. With 5 cm separation (to discriminate sounds coming from your sides), you'd need 550 kHz.

Since sound waves are ~10-10,000x lower frequency than that, you need to be able to measure pressure very precisely to distinguish two waves. Rough rule of thumb is 10x, so you'd need up to 1/50,000 precision microphones, or 16 bit. Thats an absolute minimum and you'd probably want ~20 bits.

You might need a DSP and this trick works much better with some high range microphones (electrets are maybe sufficient), but all of that is well within the range of possibility... so I'm kind of surprised nobody has done this yet. I might take a shot at it.

The tricky part is the noise floor, which is only 10-1000x (in terms of voltage from the microphone) below the things youre trying to measure. That means youve got to gather dozens to thousands of samples to determine what should get through, so you need to hear something for up to tenths of a second to decide to let it be audible.

> 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.

You'd probably want a full network of microphones around your room for this to work, as standing waves will be set up at audio frequencies. It's nontrivial to handle reflections with data from a single spot.

You could do this if you could handle the reflections, but you would need sensors spread around the room (to detect sound before it was already in the cone) and it would only work at a single head height. You'd do it by intercepting the sound, sending opposite waves from above that reached the sound as it propagates across the silenced volume. If you're more than 10s of cm away from the band of silence, the desynchronization will start letting sound through.

It would also be less effective at higher frequencies unless you had head tracking, because the wavelength of sound is not far off from the size of your head.

TBF It’s not even the same company. Part of the same group, but the entertainment companies are separated from music hardware, have their own heads, their own deals etc.

It’s like boycotting Vox media because of Comcast. It follows a logic, but it feels peculiar.

On your general point, totally agree. There was a company touting to “design” everyday noise by sticking a small module we’d keep in our ear canal, the company seems to have disappeared but I was so sold on the idea. Almost permanent noise reduction, or filtering for nearby voices only would be the dream setup.

This exists today, it's just not a device, it's building materials. The more sound deadening you want, the more expensive the room will be. It's possible to deaden sound in this manner to the extent that many people feel uncomfortable[1].

___

1. https://en.wikipedia.org/wiki/Anechoic_chamber

I'm assuming one of the biggest things limiting sound cancelling is processing speed? being able to react to changing waveforms as they arrive at the ears

The silence is pretty addictive.

Same here, particularly during a time when I was living in a noisy apartment building. It was particularly difficult for me as I didn't to take sleeping pills since I'm a bit against those things.

>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.

One of the first things when I got myself an RTX 2080, was learning how to use the ray tracing APIs to develop an idea similar to what you mention. I was using the rays to model the wavefront of an arbitrary source of sound, and then, given a 3D scene of a "room" or whatever, visualize how this wave was traveling through the space and reflecting over surfaces with different parameters.

The point of this was to see if you could find/predict the spots in a room/house/building where noise is naturally damped. The visualization was very nice to look at as I modeled the wavefront as if it had an exaggerated effect over the diffraction of light on the air. I cannot find it now, but there used to be a 2000s or so tv ad for the Beolab 5 which looked very similar in essence, maybe also a bit like schlieren photography [1].

[1] https://ntts-prod.s3.amazonaws.com/t2p/prod/t2media/tops/img...

I have NE headphones but they are too big for me to comfortable sleep with them (I tend to turn in my sleep)

I put my sunglasses under my monitor with the lenses facing me and whatever is behind me. A rounded mirror works well too.

Or buy a box of standalone cancelers and stick them where you need them. Like the dog's collar.

Faster please.

Note that this is ~50% reduction in volume, roughly the difference between a loud and normal conversation. Noise cancelling headphones are more like 75%-87%, the difference between a loud conversation and a whisper.

Yes, it is extremely hard. The question is though, can it be done? Phased arrays are insanely hard as well, they do work though.

In the 80's there was a free space noise cancelling demonstration on a cross roads in a major city somewhere, I can't seem to dig up any references to it. IIRC that was a completely analog setup, I have no idea how it worked but they had a volume within which background noise was substantially reduced. I can't stand it when I am 100% sure that I read something but I can't find it.

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.

A back of the envelope thought. A quad-pane window with the double-pane at outside to cut down the noise, a middle air gap, and then a double-pane inside. There's an opening at one end of the outside double-pane to allow air to go between the middle air gap and an opening at the other end of the double-pane inside to allow air to flow through. The ANC can be placed along the middle air gap to reduce the noise more.

       air in
    ===      ===================
    |   noise ->   <- ANC      | 
    ===================      ===
                       air out

mic -> fft -> secret suace analysis and filtering -> unfft -> speaker

A simple filtering would be a high pass filter, to avoid random high frequency sounds from constructively interfering producing more high frequency static.

Just a random tidbit, if you listen to rtings' examples or have a pair yourself I'd suggest playing some different colours of noise to see for yourself!

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

It also works well enough to see it doesn't really do what you are describing. The energy from negative copy sound waves is being used to cancel out the original sound waves, the better it's working the less energy there is going to sound waves "escaping" to be heard anywhere else.

For what it's worth, since humans perceive sound logarithmically, a doubling sound of intensity feels like a constant (+3dB) increase of noisiness. This window would not even double sound intensity unless you're right next to it.

So for the person inside the apartment it sounds like a wall in the way, attenuating sound from outside, but for the neighbour across the street, it sounds like a hole absorbing the sound instead of reflecting it like a wall.

With enough points in a directional array it starts to resemble an acoustic hologram, with some remarkable one-way properties.

If you wanted to go really far with this, you could cover the exterior walls of buildings with dense arrays, and it would dampen street sounds for everyone in the neighbourhood, indoors and outdoors. In the street it would sound a bit like there were no buildings either side to reflect sounds back into the street, yet at the same time the buildings would still block sound from neighbouring streets.

Perhaps in future cities will do this.

— So often you won’t even notice it.

Jake & Elwood Blues, The Blues Brothers, 1980

https://youtu.be/pABvTWSxOes

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.

https://en.wikipedia.org/wiki/Roadway_noise

Also a fair amount of noise generated by cars is not the engine; for example, you have the sound of the tires rolling on the pavement.

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.

In this case, it will put pressure to avoid, or reduce, noise when possible (as it directly lowers costs). It's not only cars - all neighbors with a passion for loud music (or quarrels), repair works taking longer and louder than necessary.

Where the engine noise was noticeable was low speed intersections when cars would accelerate and the tire noise would be negligible.

While we wait for that why can't architects/planners take soundproofing more seriously (if they've considered it at all) and actually make the walls and windows inside a building soundproof. It's not even outside noise, I lived in apartments where I could hear my adjacent neighbors.

It sounds like this should work...

My kids, brought up with it, were surprised to even be told there is motorway noise, they simply don't notice it.

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.

And they do it deliberately. The concept of "loud pipes save lives" is so annoying. Maybe on the highway, but the way they rev their engines in neighborhoods is not necessary or even in town.