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