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Sound-suppressing silk can create quiet spaces (news.mit.edu)
281 points by geox 26 days ago | hide | past | favorite | 186 comments



Reading the comments here seems to indicate to me people don't know a lot about the subject areas surrounding noise like acoustics and building construction, but I think that just reflects society more broadly.

The amount of investment in mitigating noise pollution is pretty underwhelming, partly because it's expensive, I think, but largely from ignorance. I tried to get a former general manager to acoustically treat a big obnoxiously echoey open floor space and their solution was to ignore everything I said and buy some annoying white noise generators, which misunderstands the problem we had with the space. Tons of apartment buildings cheap out on isolation in a really tragic way, where the difference to quality of life could be big with only minor adjustments to plans. The most tragic from my experience: when some builder decided to skip putting a real wall between neighboring apartments' bedrooms. Instead there were closets constructed from a single 3/4" layer. That "wall" couldn't stop a snore.


Restaurants opted for ease of cleaning about 40 years ago and that changeover happened fast enough that some adults here probably never really experienced a restaurant situations where you could have a conversation without raising your voice.

Long ago when Red Robin still had good food, I didn't want to go there because it was loud as all fuck in their restaurants. Now every restaurant is exactly the same.

Wearing earplugs while chewing is a very strange experience.


I’m looking up photos of restaurants 40+ years ago and struggling to find any obvious acoustic differences in their designs (I do notice carpet seems more prominent?) Do you have any examples of what they used to do better?


Booths, designs, and acoustic tile ceilings off the top of my head.

They went with easy to clean floors and took out the acoustic tiles leaving the ceilings and air handling systems bare and echoic.

In fancy buildings you also had a lot of decorative wood and molding breaking up the sound. And those embossed tin tiles, covered with a few layers of paint.


Obviously it varies widely by restaurant and location, but in general I'd agree with the statement that restaurants are a bit louder than they used to be. I'm talking about table service restaurants, rather than fast food. I think the reason is probably that real estate is more expensive now, so restaurants are trying to pack people closer together. Architectural styles are different as well, with spaces being more open, ceilings higher, and more hard surfaces (how many new restaurants have carpet?). There may be differences in people's behavior too, but I can't say that for sure.

For a while during covid, a place I would go to on occasion had full-height plexiglass dividers between each booth. It made such a huge difference in noise, I was sad when they got rid of them.


The people were well mannered, nearly every single one


Red Robin isn't exactly the type of restaurant I would think of when I want a quiet table - it is half a sport's bar after all.

If you go to a nicer restaurant, you will get a quiet table. It's the type of restaurant that matters - not so much acoustic design.


No quite the opposite. It has for a long time been the loudest place I knew of, but other places have narrowed the gap.


To me it is always a crazy feeling to visit some old school restaurant or bar with heavy drapes/carpets/textiles covering the flat surfaces. They have a feeling of almost being haunted/enchanted, but the exact reason isn't necessarily obvious. The sound of people talking around you takes on a peculiar quality and feels simultaneously warm and more distant than it actually is.


I miss the big overstuffed booths. I don't like the person behind me wiggling, but I didn't realize how much sound they ate until they were gone.

Where are you finding these old school restaurants? We need to make lists.


I once paid someone on airtasker to research me ten cafes in Melbourne that have carpet. They only found one, and I already knew it. It has since closed.


Wetherspoons (pub chain in the UK, divisive in that it is a hive of villany while simultaneously being one of the few places you can get a well kept real ale) have individual carpets in each of their venues. This has, as you can imagine, become a hobby.

https://www.wetherspoonscarpets.co.uk


Amazing. I can't really wrap my head around the idea of a chain pub.


How would you objectively measure the sound level in a restaurant? If we could sort that out we could start making lists.


I'm pretty sure you could measure this with a mobile phone app, if such a thing doesn't already exist. I've already many times used such an app to measure acoustics in a room as part of the setup process for multiple brands of home speaker system, they emitted a range of frequencies and presumably measured the result using the microphone.


It'd be great if there were better ways for consumers to understand what they're getting.

A semi recent house hunting trip involved trying to shout between rooms, going outside and banging on pots and pans. Very informal ways of trying to guess.

It's be wonderful if there were some standard ways to assess, that builders could advertise. Figuring out how to make a rating that is both not crazy expensive to assess, and also meaningful enough that consumers place some level of trust in it isnt easy.

But wow, it feels like there has to be visibility into what we get to drive change. And right now there's just so few ways to know what you're getting.


There is a standard, Sound Transmission Class [1]. STC-50 is generally considered to be a good level of sound isolation. I have no idea if houses are commonly constructed with a concern for this rating though.

[1]: https://en.wikipedia.org/wiki/Sound_transmission_class


The particularly frustrating part is that is usually way cheaper to put sound barriers during construction, than retrofitting later on.

We have been discussing this with my neighbors. We are both committed to eventually pull the trigger to retrofit, but the initial estimate is $70K and one apartment being under heavy construction for months...


I’m struggling to understand how something along the lines of ripping out the existing drywall, rebuilding a few walls worth of framing with offset studs, and filling them with rockwool would remotely approach $70k for maybe 40 feet of wall in an apartment / condo. $10k, sure, that’s easy. What is the contractor proposing?


Maybe you should arrange to do it at the same time and get temporary rentals somewhere else.

Presumably you're doing a shared wall, but having the plumber or electrician out for two jobs is probably cheaper than having them out twice, right? Especially since there will be similarities in the levels of stupid they find in the walls.


It is a floor/ceiling situation. But the floor as a nice old intricate hardwood floor, and ripping it off would be a shame. Looks like we can do the sound insulation fro the ceiling of the apartment downstairs, but

1. It requires the occupants to vacate

2. It is expensive

3. It is difficult to estimate the change it would actually provide


N=1 but in my personal experience most people don't care about loud sound levels anymore. Neither when they produce it nor when they are experiencing it. I blame two things: a) they are already deaf anyway b) I am getting grumpier and have always been more sensible to noise than others.


> ...most people don't care about loud sound levels anymore.

It's probably less this and more (at least in the US) that it's very, very, very hard to find "multi-family" housing that's not soul-crushingly substandard [0], so at some point you just give up and try to do a reasonably good job of balancing "living your damn life" with "not making so much noise as to be enormously obnoxious too often".

[0] It might be true that very few USians have ever lived in a place with actually adequate acoustic insulation... so very few folks even would think to look for it.


I use earplugs :-)


You ever eat while wearing earplugs?


For some reasons I can't use earplugs much :/.


À quieter world would be life changing. It’s incredible how low tech we are in regard to sound.


From my own experience, it is life changing.

I grew up in São Paulo, Brazil, an extremely noisy city mostly due to traffic: old vehicles, motorbikes with open exhausts, cars honking, noisy trucks passing by residential neighbourhoods, an airport inside the city (with take-off and landing ramps over major residential neighbourhoods, including one I lived at), etc.

Moved to Sweden more than a decade ago and lived in very quiet places here, nowadays right in front of a forest with a couple of lakes nearby, and I simply cannot spend more than a few weeks back in São Paulo after getting used to the quietness. I feel much, much more stressed just existing there, even inside apartments on the 20th floor, even on the "quieter" parts of the city, it's a physical feeling that I do not shake off until I'm back home in Sweden.

One can get "used" to noisy environments but the difference it is to live in quieter areas is really hard to describe, I don't think I can tolerate living in noisy environments after seeing how life is on the other end of the spectrum...


I also grew up in a Brazilian capital and during vacations I’d go to my grandma’s place in a farm about 2km away from a small city in the countryside.

Even to this day, one of my best memory of that place is the quietness I could experience by sitting at wheeling chair in the front of the house and the only sound you’d hear would be the wind, birds and sometimes chickens nearby.

Nowadays it isn’t the same sadly, because the city grew enough turn the road at the front much more busy. Now there’s a motorbike or truck passing by every 2 minutes, which spoils the whole experience.


I live in São Paulo and I noticed that contrast when I visited the central area of Kopenhagen. It was impressive and delightful how quiet that neighborhood (without cars) is.

Of course I still can tolerate the noise, since I still live here. I am used to it and, most of the times, I don’t consciously care. But I do appreciate and miss the quietness.


I had a similar experience when I moved to a very rural house for a couple of years. It was extremely comfortable.

Whenever I got back to the city, I felt overwhelmed.

I ended up living in the city and getting used to the noise again. I made the conscious decision to do so because I felt like I limited myself a lot in the places that were acceptable.

Comfort is it's own prison.

I wonder, though, if there is some kind of gain I miss out on by getting used to discomfort.


The introduction of electric vehicles has made Spanish cities much quieter. The youth can hurtle around on their electric bikes / scooters in the wee hours without waking everyone up for miles around!


In NY electric bikes haven't made much of a dent in sound pollution, there are still fat slobs on their Harley's disturbing blocks and blocks of residents either at night or during the day. Hoping I can drape this silk over my ears or something...


Interesting? I don't generally find forest to be quiet. The cricket noises, shuffling leaves, etc keep me up. Of course city noises keep me up to but suburbs are often quiet


Suburbs are bad in terms of noise. The biggest sources of noise I heard were (gas-powered) lawnmowers, the weekly garbage trucks, snow plows, car traffic, and air conditioners.


For me it's leaf blowers. For years there was a lawn crew that would run a leafblower outside during a regular conference call I had and I would have to stop what I was saying while the guy went by a quarter mile away from me.


I don't enjoy absolute silence at all, quietness for me is low intensity natural background noise. Shuffling of leaves, birds, crickets, wind through trees' canopy, a stream of water, all of that is very much soothing (and wanted) noise for me.

I've been around a few suburbs in the USA and they aren't quiet to my ears, they sound dead for a lack of a better word. Dead with the odd noise from a car's engine and tyres (usually a pickup truck), lawn mower, leaf blower rushing through it.

Absolute silence is not even natural, it gives me the creeps when I'm in a deafening silent ambient.


suburbs are the worst.

Natural noises have a rhythm that doesn’t stress us out and wake us. Methodical.

A busy road can mostly start to blend into white noise. Unless it’s absolute sociopaths honking in residential neighborhoods.

Suburbs though have leaf blowers that your asshole neighbor uses 2 hours before it’s legal to use it.

That noise is inconsistent, and it is the worst sound. Some people just suck though.


>> Natural noises have a rhythm that doesn’t stress us out and wake us.

Florida. Key West. Protected bird species. The parking lot roosters. Nothing methodical about them.


You seem to think the issue is noise, but have you considered noise might just be the most noticeable symptom of general city living? i.e. having much less personal space, nature, privacy, and free time to spend in them?


I had a great time living in cities, and still miss it. It's not an objective choice, depends absolutely on your preferences and lifestyle if city living is worth it or not.

Having less personal space, privacy, nature, etc. are trade-offs for what a city provides if you are into city life. I don't live far away from the city centre but have nature around, depending where you live on Earth it's not mutually exclusive to have access to both.

So the issue is noise, the rest are trade-offs one can make but I'd venture to say that almost absolutely no one would choose "noisy environment" as a preference for their lifestyle.


Ok, so what are those place where one have lot of personal space, nature , privacy and free time but very noisy all the time.


A quieter world is one where the outdoors is quieter because we stop producing so much noise in the first place. This would benefit us and wildlife, which are very negatively impacted by not just our classic pollution but our noise and light pollution too.


You might be forgetting about how loud birds can be. At least twice a week I'll wake up to birds chirping until at least 7am.

They are extremely loud, second only to no muffler cars and sport bikes blasting through deserted back roads.

If you live in the woods with trees, they'll sound as loud as the ocean. If you live near the ocean, well that's always loud.

The biggest offenders are:

1. cars/trucks 2. birds 3. airplanes 4. ac units 5. ocean 6. wind with trees

You'd never know trees sound like the ocean if you aren't around trees. Trains are loud but intermittent. And trains don't run very often anymore where I am.


There is a couple of conected rail spur lines near less than 500yard from my bedroom window which BNSF have decided to uses as make shift switching yard rather than the actual switching yard on the other side of town. Occasionally it is building shakingly load.

Unrelated. To the noise but just as obnoxious, They also seem to get a pervasive joy in cutting town in half by parking their trains in the main line running through the middle of the town lengthwise. I understand the rail line was here first and the town grew up along the length of the track, but why they cant park their train on the miles of empty straight track outside of town. It boggles my mind.


What about lawn mowers/leaf blowers/snow blowers? And dogs.


Cicadas. Jesus Christ.


DDT helps with the birds.


So does a pellet gun.

GP is very right. To this day, I know that if I don't go to sleep until ~03:30, I might just as well stay up - when the birds wake and start making noise, I won't be able to sleep at all. Cars, trams, trains, I can tune out. There's something about bird chirps that makes them impossible for my brain to ignore. It's worse than loud snoring.


Interesting - I love the sound of birds and can go right back to sleep when they are chirping outside and I have the window open. Road noise on the other hand...


earplugs


Agreed, its one of the many reasons I cant wait for the shift from ICE vehicles to EVs, they are just so much quieter.


If you're nearby any moderately busy road it's not the engine what makes noise but the tires and then air going around the car. Engine/exhaust noise is a problem but easy to solve


> Engine/exhaust noise is a problem but easy to solve

It's easy from a technical standpoint but practically impossible from a human one. The vast majority of people simply don't notice or care that some large percentage of vehicles are intentionally modified to be louder than the legal maximum. Police won't enforce it, and most citizens barely register the noise as present, much less a problem.

Banning ICE vehicles altogether may very well be the only thing that actually gets the problem solved, since that actually has more momentum behind it than enforcement of existing noise regulations does.


I'm not sure "large percentage" is a statement I'd agree with, my searching skills are failing me, do you have any kind of source for that? I'd be shocked if it was over 5%...


I live near a medium-busy street. I haven't seen actual numbers but it wouldn't surprise me if at peak hours there are over 100 cars passing per minute.

If 5% of those are overly loud, that's an average of a very loud noise every 3 seconds, and most of them will take somewhere between 5 and 10 seconds to come and finally go away. If you don't think that's large, we have very different noise thresholds.


I guess "large" is subjective. 1-5% is the ballpark I have in my head based on experience, which qualifies as "large" to me when I get passed by thousands of cars a day.

The hard numbers I'm aware of are about motorcycles, which have much higher rates of illegal modifications than other vehicles. This source documents a bunch of other sources, with estimates ranging from 40-70%:

https://noisefree.org/sources-of-noise/motorcycles/


People that purposefully install loader than necessary pipes on their vehicles ought to be forced to stay awake by having a marching band play nonstop in their bedroom until the loud exhaust pipe is removed


> If you're nearby any moderately busy road it's not the engine what makes noise but the tires and then air going around the car.

You cannot even hear modern ICE cars running unless you are really close to them. My neighbor's garage door opener is louder than his ICE car...

Road noise is tires/air like you mentioned. Not a real way to deal with that.


I found this to be true for cars and maybe trucks, but not for motorbikes. Some extreme motorbikes rattle all parked cars and trigger alarms.

When Harley-Davidson and other moppet/scooters would be all electric, that would be quitter.


"When Harley-Davidson and other moppet/scooters would be all electric, that would be quitter."

Not that easy, the electric Harley is intentionally louder than the combustion version - because people want them loud.

(I am not a fan of banning in general, but banning noise is fine by me)


Yep, there are plenty of ICE vehicles that are quite. A large number of cars/small trucks that are loud are designed that way because the roaring engine noise sells the car.


I believe it bas to do more with vehicular speed than business. At low speeds, engine noise dominates; on a freeway, it’s the tyres.



Yes and no at the same time. Tire noise is significant which is also a function of vehicle weight, speed, and tire design. You tend not to notice the tire noise as most of our interaction with cars is in places like parking lots where engine noise is much more pronounced.


Depends what we are talking about. In Europe, uber EV moped drivers are sooooo much nicer than the regular ones. Most of our interaction with cars are on side walks, along moving cars.


There is still honking, car alarms, and bass


99% of noise is cars and motorbikes. The correct approach is not to invent some high-tech workaround but to go after the source of the problem. Otherwise it's like spending time micro-optimising a program that solves the wrong problem.

We don't even need to do anything radical like getting rid of cars. They can be quiet. Just ban loud vehicles. Force the use of quiet tyres on the road. Do not allow modifications that remove silencers etc. to be used on the road. Race tracks already implement a SPL test for cars at the exhaust. It would be dead easy to implement this for road cars. Already you've probably eliminated the need for anything high-tech for most people.

Then, for the next level, we need to keep driving cars out of our living spaces. Considering the bicycle exists, there is no need for people to transport their bodies from the outside of town to the inside at an average speed of less than 15mph[0]. It's insane.

[0] https://www.london.gov.uk/who-we-are/what-london-assembly-do...


Very true. One of the remarkable things about Dutch cities is how quiet they are. Sometimes I step outside and just hear nothing and it's almost unsettling. Never experienced that in cities at home in Ireland were cars dominante, even in cities less than half the size.


In Switzerland I believe they have a noise ordinance on Sundays - no loud noises, incl. especially things like lawn mowers allowed on Sundays.


Unfortunately that’s a social problem that one person can’t solve alone. Here in Brazil it seems to be a common problem that individuals looking for attention will modify their motorbikes to be extremely loud and I’ve never seen this kind of thing getting much outrage from other people. They treat it as normal and police seem to have more pressing things to worry about.


In Paris they added automatically ticketing noise/detecting cameras.

It’s a matter of people wanting it.


Really? How does that work if two motorcycles go by in parallel and only one is "extra-loud"?


I guess it can use the time delay between two different microphones to figure out the direction.

And I guess if it can’t be sure it won’t ticket.


Just because there are bigger problems, it doesn't mean there isn't demand to solve smaller ones.

For example, most of the churches where I live have a big meeting room underneath their main worship space. This room has curtains to divide it into smaller spaces for a dozen or more different meetings, including Sunday school, where a dozen (often noisy) children might be in each room.

Having curtains that genuinely reduce the noise between the areas would make a huge difference! It would reduce the demand to build new buildings with separate walled rooms that wouldn't be used most of the time.

Adding flexibility of use to larger spaces with a variety of demands is a problem worth solving, even if it's not as big of a problem as motor vehicle noise in large cities.


> 99% of noise is cars and motorbikes.

It depends on where you live. My apartment building is older, built before acoustic norms came into effect. I can hear my neighbor two floors up wake up in the middle of the night to take a pee.

I have 0 issues with traffic or other city noise, even though I like having my windows open and live in Paris, one of the densest cities in the world.


> 99% of noise is cars and motorbikes.

I live atm in a place not too far from an airport: I see planes at a distance several times a day, big ones.

I cannot hear them: triple-glazed windows everywhere in the apartment. It works.

I hate noise: since forever I assemble (or have the shop assemble for me) PCs that are extremely quiet. Otherwise I will hear it. AMD 7700X CPU in "eco" mode (in the BIOS) and Noctua cooler/fan, Be Quiet! PSU, Be Quiet! tower. No GPU besides the CPU's iGPU (so it's fanless). I cannot hear that thing.

Then I love music. I'll hear that one loose bolt that did detach and is now vibrating in the system ceiling when I listen to music.

Noisy fridge, fans (there's one in one of the toilet), this or that device humming: there are many source of noise inside your place that can be really annoying when your place is quiet.

Besides the triple-glazed windows, the (small) building is well built: no common walls with neighbors on the same floor (it's the stairs and elevator that do separate the apartments). Only 8 apartments. Very smart architecture. Ultra quiet.

> The correct approach is not to invent some high-tech workaround but to go after the source of the problem.

You've never tried a place with properly installed triple-glazed windows: you'll be surprised. I'm not saying cars shouldn't be less noisy but making your living place quieter ain't that complicated: (quality and properly installed) triple-glazed windows and call it a day.


These are all valid points, I also very annoyed at noisy home appliances (fridges...), but I'm always shocked by how loud it is as soon as you step outside. I remember during the first lockdown I would take walks out in Paris and it was so quiet and peaceful; the sheer quantity of decibels originating from motorized vehicles is insane.


I also like fresh air, though.


Happy for you, most houses I visited in Canada are so poorly insulated (noise and temperatures) that it's laughable and triple glased windows would just move the problem from windows to walls.

Asked a home building company if they build with concrete (not that you couldn't insulate a wood construction though) and they scoffed saying it would take 15 years to recoup the costs through energy savings... Which doesn't sound that long to me, it's a house not a car


Cars aren't the sort of noise that I primarily care about. Neighbors with their god-awful dogs and children that scream and hit the walls 24/7 are far worse.


> 99% of noise is cars and motorbikes

See Not Just Bikes' "Cities Aren't Loud: Cars Are Loud": https://www.youtube.com/watch?v=CTV-wwszGw8


> 99% of noise is cars and motorbikes

If you live in the city, sure. But 99% of the noise I deal with is family members going about their lives. Would love a solution to help prevent sound transfer indoors, so that I can focus (and sleep) better.


Go countryside, they said, it'll be quiet.

Except for: tractors, harvesters, mopeds, quadbikes, chainsaws, circular saws, nailguns, lawnmowers, leafblowers, snowblowers, diesel generators, motorboats, skijets, snowmobiles.


This.

I moved to a countryside 2 years ago, escaping from city noise. Now, I’m going back (although to the outer, more quiet side of the city) because I’m going mad - lawnmowers, dogs, tractors, diesel generators, dogs, dogs, lawnmowers, dogs, …


Already exists, same as is used for any other soundproofing. Rockwool insulation, resilient channels and a second layer of drywall, mass loaded vinyl, acoustic panels and tapestries (can hide some more mass loaded vinyl in there too), acoustic adhesive, scored screws to kill floor squeaks. They're all quite expensive but hey! Very DIY accessible.

For exterior noise the biggest bang for the buck is replacing windows. I had some soundproof windows put onto my previous house and you could close the door on a parade going by and not even know it was happening.


Curtains add a flexibility to the use of space that walls do not. If I only have overnight guests very occasionally, I don't want to wall in part of my living room to accommodate them, but I'd love to be able to hang a curtain from some removable hooks that would give them some real noise privacy.


Tell your family to stop motorbiking to the bathroom in the middle of the night. Bam, problem solved.


Where I am right now 99% of the noise is coming from animals. The birds are non stop dawn til dusk and there is currently a dog barking...


Same here. Loudest noise is one of my servers, but after that is birds and cicadas. I wish I could make the birds shut the hell up, but that sounds like the start of a horror movie.


> Force the use of quiet tyres on the road

Could you expand on this? Above 20-30mph tire noise is the dominant noise from vehicles [1] and I haven't yet found a reference that shows significant reduction by choice of tires

Personally I think we need to put cars underground - without tunnels we'll be in traffic hell forever[2]. And imagine the quiet.

[1] https://www.fhwa.dot.gov/pavement/sustainability/articles/ti...

[2] Elon Musk


When you buy tyres they actually come with a dB rating, at least in the EU. See: https://www.protyre.co.uk/car-help-advice/tyre-selection/wha...


Tires for my car range from 67 to 72db, which isn’t much of a range


> Personally I think we need to put cars underground

Nope, unless drivers foot the bill entirely. Tunnels are horrendously expensive to build and maintain. Projects like Boston's Big Dig cost billions of dollars, went over budget, and move a smaller number of people than a proper subway train system.

> without tunnels we'll be in traffic hell forever

Also nope. Adding more lanes just induces more traffic demand. We will never solve traffic by building more car infrastructure. We can only solve traffic indirectly - by mixing residential and commercial building, by making streets safe to walk and bike, and by building a world-class mass-transit system.


> 99% of noise is cars and motorbikes

EVs are incredibly quiet. (but yes they still honk)


We live on a semi-main road. Normal engines aren’t really noticeable or annoying. Nearly all of the road noise is generated by tires with a fraction coming from large truck engines and vehicles with broken exhausts.

Tires are shockingly loud.


Smooth roads really help with this, but no one seems to care


Smooth roads come with grip problems - especially in the rain.


The majority of noise is not from the ICE itself but from the noise of the tires on the pavement. EVs have the same issues as all other vehicles.


Only at very low speeds, past 30km/h (18mph) the noise from the tyres starts to approach or surpass the noise from the engine so they're nearly equivalent.


Yes, but then there are few idiots with modified cars (or most motorbikes in general) that are orders of magnitudes louder and can be heard from kilometers away.


There are efforts to attack the car tyre noise problem by grinding groves into the surface of the road. it's called "Next Generation Concrete Surface" I remember hearing about it on the "Twenty Thousand Hertz" podcast [0] [0] https://www.20k.org/episodes/sonicutopia


We had grooved concrete here some decades ago. Luckily they got rid of those as the noise was much worse than normal surfaces.


EVs are now required to make a noise at low speeds and at high speeds tires dominate. The best option is fewer cars, the second best option is lower speed limits (with enforcement!).


I suspect this can explain a lot of the IQ loss since it become difficult to build concentration.


Insofar as traffic is concerned, any drop in IQ would be more likely related to PM2.5 pollution levels than noise:

https://www.nih.gov/news-events/nih-research-matters/air-pol...


If we're talking about concentration, social media/devices likely play a _much_ larger part.


What IQ loss? IQ scores have consistently increased over time


I'm afraid your knowledge is a bit out of date. Even Flynn has given talks about the "reverse Flynn effect" in the past three decades. IQ scores have been going down.

Recently: https://www.sciencedirect.com/science/article/pii/S016028962...


My suspicion on this is not the noise from the device, or even the devices themselves are the problem... It's that we sit on our ass all day watching/listening to them. Brain health is correlated to exercise and movement.


As I read your comment I became aware of just how loud a simple standing fan I have currently behind me is, even on the lowest of settings. Fan design feels comically lacking in this regard. I am sure it could be much quieter even when faster.

Dyson fans are meant to be quieter, but for a premium.


Yes, but then more people would start to hear their inner voice.


We know quite a bit about how to block and mitigate sound the issue is it's transmitted through the air which we want to move around for other reasons so it's tough to block one without making stuffy areas.


Judging by the figures in the paper, it appears to attenuate low frequencies better than high frequencies, which is perhaps to be expected judging by experience with noise-cancelling headphones. This could be a game-changing complement to traditional acoustic treatment for recording studios and other acoustic spaces, where low frequencies are traditionally much harder to treat, requiring much larger and more expensive panels.


I'm a mix/master engineer, and I just skimmed the paper to look for attenuation potential of this new material. It looks like they only tested above 100 HZ, which is still alright for conversation, but not for professional recording studios.

As you can imagine, the low frequency attenuation isn't great. But the performance of higher frequency attenuation is pretty good. I think this material would work well for meeting rooms, and perhaps restaurants. Not for recording studios.


Use this silk material as a cover for bass traps? Win-win


Bass traps do little under 40 Hz where waves are feet long so good luck if you have a noisy HVAC, elevator or whatever running the vibrations


Low frequencies travel further, in my house high frequency road noise is annoying but tends to come and go quickly but low frequency road noise I can often hear from literally miles away.


"Farther" not just in a straight line but also around corners and through structures.


I really, really hope the space of acoustic room treatment is incredibly inefficient and somebody can 10x a solution at some point. There is a lot of good that could be done by establishing acoustic treatment and managing noise (transmission) as a requirement for any type of indoor and outdoor construction.


The massive additional cost to construction is likely what holds it back. If you've ever looked into soundproofing, its a deep rabbit hole that basically boils down to you have to physically isolate all the physical materials that could transmit noise. So basically you have an inner-room built inset from an outer-room shell with noise dampening attachments at all the points they meet.


the cheapest way when I worked construction was doubling the drywall. Put up two sheets instead of one on all walls. Typical insulation in the walls was fine but double sheeting led to a significant reduction.


cool to hear - I have existing rooms that I replaced hollow core doors with solid core doors, but it didn't help much. I thought I would have to rip off gyprock to add better sound insulation, but maybe just adding another layer might help...

I assume it would only have to be on walls adjacent to other rooms, ie not exterior walls? And how did you really know this worked? Did you ever live in a room like that, or try this on someone who reported it helped back to you in some fashion? Thanks for the idea :D !


I worked on 2 houses and partially a 3rd where the buyer asked for a 'man cave' room. We'd put nicer insulation on all sides and slightly gap the board from the wall (hard to explain) then double layer the drywall. We'd use thicker board typically used on ceilings for all walls, and carpet the room (makes a difference), along with a solid door. A good window if it had a window, like double pane or a window marketed to be sound proof.

Then most importantly we'd go around the cracks of the room with a can of foam insulation and seal every hole we could find.

These rooms where pretty quiet. I can't say how much of a difference just the drywall would be, but if I wanted the cheapest way I'd do foam sealing and double drywall. Tearing everything out to replace behind wall insulation would only be something I'd do if there was zero insulation in the walls. I guess you could tell by knocking the walls with your hand. If they sound hollow you'll know. If you have a friend with a sound proofed room ask to walk around and get a feel for the space so you'll know what to aim for.

Drywall is easy to replace though and something more diy-ers should try more often imo!


the problem in buildings is the building transmitting vibrations. That's why it's hard to find a solution afterward.


Indeed.

Anecdotal example: I'm currently living above a cafe, with an entire floor (with an office in it) between us and them.

When they drag the tables and chairs around, we can hear it easily, because it sets up a vibration through the structure of the building. Took us a long time to realise where the noise came from — it sounds like it comes from above, but the flat above us has been unoccupied on some of the occasions we heard the noise, and we were only able to confirm the real origin by me being outside the cafe watching them while my partner was inside, and with the two of us on a call so we could directly observe that what the cafe staff were doing correlated with the noises he was hearing.


Is this a “we didn’t consider it” problem, or a “it’s part of how we build these days” problem?


Both, increasingly the later, in a mix of cost (and who shoulders it and when), regulation and in how far we design around our shortcomings.

For example, a window is a very obvious thing. Obvious things, we value. A balcony. A garden. These things either exist in some capacity or they do not, and it's easily to mentally check them.

Acoustic treatment is more akin to differences in heat insulation. You notice it, when it's a problem, at best. Or it's a problem that you pay for all the time, but you don't even know how much. If buyers/renters don't value something directly, even if it impacts the negatively, the incentives on the builders end to spent on it are understandably low. It requires regulation to be done properly (which a lot of countries have understood and, hence, regulated).


Both I'd say. We consider it less than the thermal problem since there is less regulations about noise, and it's also part of how we build today since there is a tradeoff between price, sound isolation and even thermal isolation. But we do have good techniques.


It got real expensive here to build multifamily housing in part because you have to put acoustic separation in shared walls now. That and a tight construction market are putting the brakes on what would otherwise be unwise levels of growth. And therefore unlikely to change except by accident.


Cars. Cars are the problem.

Don’t make buildings cost more. Stop the noise.

At the very least, you take a muffler off your Harley, you get your Harley taken away.

Jail.

Consequences for antisocial behavior.

Taking the most expensive fiber in the world and then adding gizmos to it is the wrong way


> At the very least, you take a muffler off your Harley, you get your Harley taken away.

This is one problem that I think is eminently solvable. Virtually nobody wants these vehicles in their community.

The reason the problem persists is because they disappear out of sight and without evidence before anyone can do anything about it. Just as soon as they annoy everyone, they're gone.

(And let's be honest, the police aren't particularly incentivized to pull these people over, given that they're almost by definition selfish assholes who are difficult to deal with.)

One solution I've been daydreaming of is a device that could cheaply and reliably capture video of passing vehicles (detailed enough to read license plates) and assign a loudness rating. The loudest vehicles could be shared to a database, and the data made freely available to whatever agencies are responsible for issuing tickets.

I suspect that with a large enough body of a evidence, the existing laws become much easier to enforce.


Such noise cameras already exist in some places.

Unfortunately, in the US, we already have a problem with "ghost cars". I see plenty of cars in California with no plates, fake temporary tags, plates with the retroreflective material stripped off, covers that block the view of the plate, etc.

So those loud motorbikes are just going to bend their plates out of sight of the cameras.


the police are the same people or at least the same kind of antisocial


I don't care about cars (I'm sure they are a problem for many, but not in my particular street). I do care that I can't sing and play instruments late at night.


As someone who teaches an introductory course on acoustics and the nature of sound I have to say that I can't see how that would work.

The main problem is that acoustics are affected by everything within a room because sound from humans and most loudspeakers spreads in a somewhat special fashion. So your acoustics problem is usually:

1. Sound goes everywhere and it is not directed just to the places where ears are. This way the sound waves of me speaking also hits the ceiling in a million places and these reflected signals come at you with varying time delay and mix with the direct signal of my voice. If the surfaces of the room are hard, you will have those sounds bouncing around till they loose energy.

2. On top of that every room has particular frequencies that it resonates with to create resonances that make that specific frequency ring longer or the room seems to suck the energy out of that frequency. These are called the mosal frequencies of the room.

One remedy to 1 is to make big chunks room surfaces absorptive or to put more stuff into the room that scatters the souns waves earlier. So: carpets, special ceilings, curtains, acoustic panels or foam at the walls, etc. Tirns out human flesh is also quite good ar this, so packing the room with people also helps.

Another way to deal with 1 (if you can't touch the architecture) is to emit souns in a very directed manner only to where ears are. Nut that means microphones, a mixer, 5k€ per piece beamforming loudspeakers + personal with enough acoustic knowledge to place them in the right spot and steer the beam in the right way etc.

The room mode thing is almost luxury to treat by that point, but it typically involves changing the room geometry, and building buying specially tuned absorbers that are tuned and measured within the room. Depending on how low you want to go with the frequency of your acoustic treatment these absorbers become big fast and can take a third of the space in a room.

In my experience the main problem is that people building rooms treat acoustics as some afterthought, something expensive that you need to avoid to save money. In fact the planing stage is the cheapest place to improve acoustics. You could for example not decide to make a conference room with pure concrete walls/ceiling and a tiled floor, because any person should be able ro imagine the acoustics of that room.

I had to work in a newly gallery space that had worse acoustics than a church. When I asked the architect about the acoustics and why the delay times don't fit the purpose, the architect said for money reasons they ordered "a better looking car deck". The acoustic treatment of that space will cost way more than if they just hadn't decided on a barren ceiling and pure concrete walls.

The same points go for insulation between rooms. There is no magic here, just physics. If you want insulation you have to put mass between rooms and decouple/dampen their interactions. You either do that from the start by building things correctly or you do that afterwards by building another floating room in your existing room. In both cases you have to inspect painstakingly for acoustic bridges, sometimes a single nail touching the outer wall in the wrong way already bridges enough sound to make it noticable.

We know how to build good sounding and well insulated spaces. People just don't want to pay for it. We know how to reproduce speech in acoustically horrible places, people just don't want to pay for it. Acoustics is perceived as an abstract, high-brow, fancy classical-music-topic. That is, until people perceive how straining bad acoustics can be, then they want sudden magic solutions.


Perhaps two sheets of material, one that acts as a high resolution two dimensional microphone array, the other that acts as a high resolution two dimensional speaker array with the microphone array a fixed distance from the speaker array. The microphone array detects sounds, the distance between sheets equals the processing delay as it relates to the speed of sound, and the speaker array cancels the wavefronts. Maybe two layers of microphone arrays would be needed to estimate the angle of arrival of the sound pressure fronts. That wouldn't help the problem of sound that travels through walls, ceiling and floor to the other half of the room (or to a different room). You'd need sound cancelers in front of or behind every room surface in every direction, and bass traveling through a floor seems difficult to stop since it would require a lot of energy. Still, a vibration isolated bed with these magic sound canceling sheets surrounding it might be fairly effective. Letting the sound of smoke alarms, air raid sirens, police sirens, etc. through in emergencies could be an issue. Sounds expensive using today's technology though, one sheet might require a fair amount of computer processing for say a 10,000 x 10,000 array of microphones and the same size speaker array. Starting with proper sound isolating construction might be cheaper. Though if mass produced the cost may eventually go down a lot. It doesn't necessarily have to solve all sound problems, just the ones some people find annoying. Perfect silence is in fact fairly spooky and freaks some people out (if you've ever been in an anechoic chamber).


> I have to say that I can't see how that would work.

Isn't that exactly why this is a notable discovery?


I think you misunderstand my point, there are many ways how one can do acoustic treatment, but even a better silk isn't a magic bullet. Any truly "magical" solution is going to be hightech metamaterial DSP-and-sensor-heavy and cost a hundred grand or more for a small room. I can imagine that.

What I can't imagine is that ever becoming an economically viable option.

What I can imagine is that we get better materials, like that silk, with crazy absorbtion coefficents on a small volume. But those are still going to be magnitudes more expensive than the best acoustic foam you can buy today and those still need to be placed in the right spots by someone who knows what they are doing. And the person responsible for the room needs to be able and willing to shell out the money for both. That ia why in practise we have bad aounding places and strained brains because your brain needs to focus hard on understanding acoustically smeared words.

As I said, this isn't a unsolved problem. It is just that people don't want to pay for the existing solution and many people don't even think about preventing it as they build new stuff as this is not on their radar or treated as a luxury problem.

My solution would be to make the building code requirements when it comes to acoustics and sonic insulation much stricter, especially if the purpose of a room is to talk/listen within it.


Having sound sensitivity I’ll buy this the moment it comes out.

I’ve lost countless nights of sleep only because neighbors behind the walls had normal meet conversations past 12am. I really try to not be PITA but it’s my wellbeing vs theirs in the end. It’s a rental apartment so some are sympathetic and some are not.

In case you wonder why not ear plugs could help: they don’t work because I can hear my blood flow and heart beat and it’s even worse.


The best solution for these cases of mild inconvenient noise is to mask it with more noise, ideally a fan or a pink/brown noise generator, or even sounds of rain or a waterfall.

You want the noise to be indistinct enough that your mind won't focus on it. So avoid a bad fan that has a whiny pitch, that will drive you crazy.


Try Mack's silicon earplugs. they are not to be placed inside the ear canal but only to cover the entrance from the outside. so no unpleasant pressure, no heart beating etc. using them for years.


Whoa, they look amazing and could be a game changer. I ordered a box immediately, thanks for sharing!


You can also get custom fitted earplugs from an audiologist. They are wonderful. Extremely comfortable and they don't press on your ear canal, so you don't have any pain or hear your heartbeat, etc.


Just be happy you don't live below someone who stomps around their apartment all day and night. The deep thud of heel strike vibrates your body and because it's very fast attack/low frequency noise, it's very hard to block the sound itself. Ear plugs do nothing. It's like living inside of a drum.


You think this curtain will help ? Article says it vibrates when it's working so that will probably disturb you as well.


It's give and take, it will help more than bare hard wall.

Heavy curtains are the cheapest/easiest way to "sound deaden" a normal room. Their fabric surface area is greater than the bare wall, and the weight helps isolate vibration. Thinner ones will be less effective. Never effective as foam, and no method is as effective as actual mechanical isolation (IE a room suspended in a room)


How so?


Have you looked into the current solutions? MLV sound barriers such as curtains, for example, can help with this.


No I had not. Thanks for the comment, I’ll check those out!


I use bees wax earplugs when I sleep, and they are 5x better than the standard foam earplugs, imho


I'd be curious to know how would it damp lower frequencies that travel also by contact. Sound proofing for mid-high frequencies is easy if one doesn't aim at studio quality: just use wood and foam panels, break facing walls and angles with acoustic absorbing objects and cover every window or mirror (read: glass) with a thick curtain, add carpets on the floor and panels on the ceiling, and you're done. (hint: a $5 foam panel glued on a thin OSB board makes a quite effective, still light and cheap absorbing panel for mid-high frequencies) However, bass frequencies will be only marginally affected by that, and depending on what the room is used for, the above treatment might turn out as insufficient: probably overkill for recording a podcast, still not enough for recording music at higher volumes like when miking a band. Treatments for lower frequencies are expensive because of the necessity to literally prevent walls, floor and ceiling from vibrating, which invariably requires them to be weighed down adding concrete layers to further lower down their resonance frequency, before adding soundproofing. Sometimes the best approach is to build a drywall room into the room, which of course is more expensive and space constraining than the wood+foam panels solution.


The silk sheet from the article is a loudspeaker.

The solution proposed in the article requires a microphone, and would have a tough time dealing with multiple sources.

It basically records the room, then plays the room back via the silk sheet, but out-of-phase. Because it's out of phase, it cancels out.


You mentioned building drywall room - a neat building technique I only learned about recently that's along these lines (but a huge space and cost savings) is a "staggered stud" wall.

https://www.reddit.com/r/Carpentry/comments/13j7o4u/staggere...


Active noise cancellation speakers. You can create small quiet bubble for your head, where you sleep.


Can’t get to market fast enough. They are absolutely right that applying this technology to silencing noise it sorely needed.


I would love if advances in material technologies would allow to design a window glass-like material that would let outside air in, but would cancel exterior sounds.


That would be nice. The next best thing is probably a regular (shut) window with an ERV/HRV somewhere.


Isn't that just better all around? Though a regular shut window isn't actually all that good at blocking sound.


I have seen such a thing in an article, though I don't know how to find it. It was a window with a square grid of circular holes in it - air could flow through, but sound waves were dissipated.



That's active electronic noise cancellation - there have been many of those described and very few delivered over the past thirty years. Presumably because it's the sort of thing that is angle-sensitive and hard to set up and maintain.

The thing I saw was just a pane of glass or plastic with large round holes in it to attenuate/dissipate sound waves while allowing significant airflow.


> The sound-suppressing silk builds off the group’s prior work to create fabric microphones.

>In that research, they sewed a single strand of piezoelectric fiber into fabric. Piezoelectric materials produce an electrical signal when squeezed or bent. When a nearby noise causes the fabric to vibrate, the piezoelectric fiber converts those vibrations into an electrical signal, which can capture the sound.

Well, that is ... disconcerting. A slightly funny and dystopian future comes to mind of world leaders having to get naked to ensure they're not being spied on by the possibly nation-state-hacked ad-tracker-subsidized clothes.


This is interesting! As someone who often struggles with noise from my environment, I'd love to have something like a mosquito net that can be put around my bed to keep the noise out.


I would love to have something like this. Even better if it comes in a portable form for the occasional visit to the office.


I'm chuckling imagining a bunch of office-workers walking around with anachronistic silk head-veils and wimples.


And CEOs with $18,000 egg chairs lined with this.


Second this, I totally can imagine buying a bead or windows curtain made out of material so I won't have to use ear plugs every night to stop hearing dog barks.


Or for snoring reduction


Cool research. The assessed conditions are very tightly controlled, and I wish they better described the sensing mechanism used for the feedback in the “vibration mediated suppression” method. but the new material approach is promising however, as it’s much less intrusive than other approaches.


Another thing textiles can do is block wind: https://research.chalmers.se/en/publication/534412


My first thought was that airplanes need noise canceling for the engine sounds. There's a real difference in a long flight with and without noise canceling headphones. Effective (better?) noise cancelation for the whole cabin would be impactful.


It's difficult if not impossible to do active noise cancellation for multiple people simultaneously.


This could be great to remove snoring noise for couples, instant seller haha


It's kinda surprising that nobody has made a product for that, because it COULD be done with a plain ol' loudspeaker playing out of phase.

Basically:

1) put a mic above one person's head, in the headboard or somewhere near there

2) record the room

3) play the room back from the same location, but out of phase

voila! Snoring cancellation.

One unfortunate side effect is that it might be quite loud for other people in the home! Because the cancellation will only work well at a single point in space; get a few feet away and it will sound like TWO people snoring. (The snorer, and the loudspeaker.)


I bet you that they wanted to do the nose cancelling method and then discovered they applying a static voltage worked much better.

I am still bit sure how well it really works.


I don't think applying a static voltage would do much. But as to how well it works,

> In vibration-mediated suppression mode, the fabric could reduce sound transmission up to 75 percent.

So about 6 dB reduction.


Thanks For pointing out that number. I didn’t see that somehow.

I was referring to this:

> In the other, more surprising technique, the fabric is held still to suppress vibrations that are key to the transmission of sound. This prevents noise from being transmitted through the fabric and quiets the volume beyond. This second approach allows for noise reduction in much larger spaces like rooms or cars.


Yeah, but I don't think that can be achieved by applying a static voltage. I think it'd operate pretty similarly to regular nose cancelling where it requires a dynamic signal, but the goal to is keep the fabric stationary rather than to produce a vibration that negates some incident sound at some position. Although maybe that really is as easy as hooking the piezo fibers up to a low-impedance constant voltage source?


Question for research: Do these sound absorbing properties also exist in plant leafs?


Would this work with fabrics so we have clothes that give us quiet zones around us?


Awesome. I’ll buy the curtains or piezo electric fiber windows


What a time to be alive! Excited at the prospect of quieter cars, better noise cancelling headphones, quieter airplanes…

My only wish is for a fabric that doesn’t involve poor silkworms.


I would buy a carpet made of this to not hear the downstairs people.


Your downstairs neighbors would probably also appreciate it!


If you came looking for actual numbers the closest they come is saying "in vibration-mediated suppression mode it could reduce sound transmission up to 75%".




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