Bricks Can Absorb Traffic Noise – Thesis Preso on Helmholtz Resonators [video]
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You can find a peaceful out of the way place where there isn't sound or people, or you want stone and concrete aplenty around you. That's weight & mass. But that mass usually has so much cost. (And it has so many inconveinences. Where do the pipes and wires go when you are working with stone? It's not accommodating like framing & drywall.)
This is so cool. This is so so so cool. It's cheating, getting one of the best & nicest things you can get, and doing it not by just cladding your world in thick concrete, but by creative use of negative spaces. By resonance. It's a vast unmaterial triumph. Using much less matter but getting so many of the same upsides.
This is the arch of victory that embodies what I hope can carry us through the stars for a long time: getting so much from so little. Making stuff that is blisteringly effective. These are the triumphs that can sustain us as we voyage on.
(It also looks like something that would be pretty easy to mass produce! A bit bulky to transport though, but maybe there are some creative solutions.)
what's expensive isn't the stone and concrete. those are cheap as shit. even graded broken stone aggregate for mixing concrete is cheap. like a penny a kilogram cheap. sand, same story. random dirt is even cheaper and works fine to block sound
what's expensive is shaping the concrete and dirt (for example, as you point out, to run pipes and wires through them, but also for things like making thin walls stand up stably)
to a lesser extent, getting it delivered is also expensive, because it's heavy, but mostly it's the shaping. that's why concrete is so popular; concrete is mud, and mud is pretty easy to shape, but it's mud that turns into stone overnight. it turns out that it takes a lot of work to shape big things
But that ain't sexy, so most people ignore it. :)
Obviously it's somewhat impractical on large jobs, and inadvisable in very strength-critical roles, but for small household / farmstead projects it's a great way to save money and get rid of ugly rubble you have lying around.
This also reminds me of some DIY and volunteer experiences installing residential fence posts. On a volunteer gig, I saw people using 200 lbs. of concrete and keep adding water until it's soup triumphally proclaim it's "the right way" while dismissing supervisors and others who knew what they're doing. Meanwhile, I was looking at depth, slope, wind risk, and soil (hydrology), and gathering site debris like rocks and chunks of metal to stick under each post so it wouldn't rot in 5 years or become the Big Dig in time, materials, or quality.
also though 'fill in the large gaps with aggregate' is what makes concrete concrete instead of cement
however, if you want to make soaring thin shapes out of concrete, you aren't going to do that with chunks of demolition debris as aggregate. even gravel won't do. for ferrocement you need an all-sand aggregate, and mining construction sand is a lot cheaper than crushing demolition debris into sand
I feel the same way about directly using or mimicking systems of the natural world. Stuff like using birds as combined pest control and fertilizer or waste water treatment.
I think we haven't even scratched the surface of what is possible, particularly with microbes. I envision things like producing glue, converting plant scraps into fibres/wood, converting toxins into inert compounds, extracting trace chemicals from a massive volume of useless medium.
Right now I think the biggest obstacle to these kinds of techniques is the lack of control and the danger of escape and mutation. Just imagine if a plastic-eating bacterium escaped a waste facility and started eating our world. I hope that with better tools and better simulation we can make it work and make it safe. It would go a long way towards lowering our energy and resource use.
Commercial helmholtz CMU products:
https://www.soundseal.com/masonry
https://www.rpgeurope.com/products/product/diffusorblox.html
Learn something new every day, and this time it was 10 minutes after I woke up! Thanks!
An acoustic jar, also known by the Greek name echea (ηχεία, literally echoers), or sounding vases, are ceramic vessels found set into the walls, ceilings, and sometimes floors, of medieval churches. They are believed to have been intended to improve the sound of singing, and to have been inspired by the theories of Vitruvius.
But then someone would say oh but then cars are dangerous when they are silent, let's install speakers in them so pedestrians can hear approaching car and move out of the way. See what's happening here? Instead of jus making a car unable (auto breaks) to hit a pedestrian, we are doing some silly workarounds (ok, no silly but cost saving) to emit noise and shift the burden of moving out of the way to the pedestrian. Again polluting city with noice.
Done ranting. Have not touched pollution, wight, speed limits and general car infrastructure :) Time to get my morning coffee.
P.S yes, i'm very much influenced by "Not Just Bikes". Youtube channel about European city planning (human/bike oriented) https://www.youtube.com/c/notjustbikes
I once lived next to a busy inrush road in a city. Once a week I could wipe black grime from my balcony desk. Every second night I would wake up from people speeding or trucks rushing through. One day I spent on the balcony counting cars. 100% of the SUVs had only one person in it. But the worst thing was the noise. I didn't notice back then, and I am not a sensitive person (I play in a noise rock band), but when I moved and was in a silent new flat, it felt as if someone had lifted a rock from my chest. And let's not think about the black grime.
Cities and cars are not a good mix, unless you own a car and don't care about the people living there. I especially dislike how naturally we are expected to yield public space to ever-bigger cars for only minor fees.
This leads to about 43,000 deaths per year in the US alone. And for some reason this is considered normal.
Don't get me wrong, work accidents do happen with ladders, and training/inspection can prevent them, but the risk stemming from ladders doesn't compare to cars.
The way society accepts risks tells a lot about that society.
- a wet road and you drive over a "moveable" section of road and as soon as your front wheels are over it jerks the rear wheels randomly to either the left and the right ans you need to recover
- a course that you drive through and randomly a wall of water emerges from holes in the street and you need to safely stop or avoid the obstacle (this teaches you about the safe stopping distance and problems that can emerge when you suddenly try to avoid things) with and without ESP
- driving too fast around curves on purpose
- trying to do similar things while multitasking in the vehicle to demonstrate how bad that influences your performance
I don't know what the level needed is in the US (I grew up in Austria), but even with that training I still feel cars are taken not seriously enough.
Collect 4 barcodes from boxes of cereal.
The best thing I have found for this type of training is autocross (tire rack presents a special defensive driver course related to some autoX clubs too). Then snow/skid pad it's just finding a deserted parking lot cover in snow and ice for some low-speed recovery practice.
Even if you own a car really. I've owned a car for the past 8 years because of how crap the public transport is. It's the only way of getting to many places. But I've never driven within my own town except for getting out of town. What I've always really wanted is an out of town car park I can cycle to with secure bike parking. That would completely eliminate the need to use a car in town. At that point I could probably do without actually owning the car and just grab one from a pool of rentals.
Unfortunately people don't know what they're capable of and insist on cars being parked right at their houses. So many people even get groceries delivered by someone else now. They are mostly just wheelchairs these days.
True.
I am lucky enough to live in a european city with very decent public transport, so for the 2 times a year I actually need a car or a transporter I just rent it. I don't need to think about my car, where it is parked, what it needs in terms of maintenance, etc. I see this as a value that easily outweighs the benefits of having a car.
But that choice is easier if you live somewhere where you can both get everywhere using subways, busses, light trains and hop on a night train and wake up in the capital of a different country. I guess you have to experience this before you realize that a life without car is truly possible, when you shape your world in the right way.
But this lifestyle became worse and worse over time and it was all due to cars.
Over 10 years I saw the roads become more and more clogged with cars. I saw cars get bigger and bigger and more and more powerful with the drivers seemingly less and less capable. I'd been using the road since I was 12. They'd been using it since they were 18 or so and only knew it from behind a dashboard. I saw more and more public money get poured into the car subsidy: "reducing journey times", making roads better for cars and worse for everyone else. Meanwhile train tickets increased, bike parking got worse or stayed the same and cars just seemed to get more and more affordable. I'm probably as experienced a cyclist as you can get but I now consider cycling on the road to be too dangerous to be enjoyable. Not to mention I started to question whether breathing diesel fumes and tyre dust in deeply was good for my health.
To add to that, just living in the city became unbearable. Car noise had become horrendous. I never heard my neighbours who lived in adjoined apartments. The only noise pollution to enter my own abode was from cars: the engines, the tyres and the sound systems (and I'm not talking about boom-boom subwoofers, just standard car radios). This really hit home one winter when we had weather bad enough to stop people driving for a week. Noise pollution is insidious: you only know it's bad when it's already driving you crazy.
So I got a car to escape the cars. Sad but true.
literally the only reason i got life insurance
Green Mobility and Share-Now are the larger companies here.
Build residences that are each bunkers with massive walls, airlocks, and HEPA filtration is probably not going to scale to all demographics very well.
I think (the US) needs more public transportation that gets people out of single-occupant vehicles without imposing time, money, or practicality costs onto them.
Or the neighbours who enjoy Vietnamese karaoke, or the neighbours having a domestic on the street.
These aren't the most fun aspects of living in a community (unless you get invited for the karaoke!); but they benefit from ambient noise cancellation.
The Netherlands
> When I was still living in the city we could talk outside at a slightly raised voice when walking or biking.
True for most parts of the city I live in too, but that's mostly because in most parts of the city there's either no cars or very slow cars or only one car within hearing distance at a time. As soon as you're walking along a busy road where the speed limit is 50km/h it starts getting loud.
It's quite possible there's some cultural influence here too. Dutch people don't tend to speak especially loudly when compared to e.g. Americans.
I live in LA and the vehicle noise is negligible on any walk to anywhere compared to the low roar of the sounds of living otherwise -- unless you happen to get some muffler-less asshole driving his shitbox next to you; but that same rule applies just about anywhere.
I guess it could be a benefit of the low speed LA traffic?
Personally anytime i'm near traffic the stuff that bugs me is exhaust and brake/clutch dust. Nothing like a hot semi truck parking next to you in traffic after a long downhill stretch to cool his brakes and douse you in friction-material fumes while he waits for the light to turn green.
No, and in fact doing that here WILL get you picked up by the cops.
> I guess it could be a benefit of the low speed LA traffic?
Oh yeah lower speed traffic is much less bad for sure. But I'm still talking about a slowish speed limit here: 50km/h
> Personally anytime i'm near traffic the stuff that bugs me is exhaust and brake/clutch dust. Nothing like a hot semi truck parking next to you in traffic after a long downhill stretch to cool his brakes
I am blessed to not live near any hills and have cars subjected to frequent emissions checks. Still, can't tell you enough how much more I like the electric buses they use nowadays over the diesel monsters they had previously.
I have a car which auto-brakes when an obstacle is ahead. Usually helps when parking in tight spots, or when backing out — its systems have wider FOV than I do, and it warns of incoming cars of pedestrians a fraction of a second before I can see them, which is good.
Except when the weather conditions or something on the road trigger a false positive and I suddenly go from 45-50 km/h to full stop. It's also a lot of adrenaline fun for the drivers behind me. Happened twice last year.
So no. A speaker is more reliable and robust and simple a solution.
You don't win against human nature.
Drink driving also used to be normal and "inevitable". It's possible to change.
This is my favourite bit about cycling. The commute is a race. It’s often with others, but the likes of Strava gamify it such that you are racing yourself too.
Also, what you describe is not necessarily in conflict with the parent. Skinny tires are good in the snow because there's less plowing effect and more pressure to grip into the snow. However, more width is generally better on icy roads.
There was recently a pro-car terrorist attack in London. I am not kidding - someome made a bomb and blew up a lamppost with cameras for reading number plates. Its hardly been reported.
Can you imagine the coverage if the climate protesters blew up a betrol station, or god forbid, if this was something to do with currst conflict in the middle east?
https://www.theguardian.com/environment/2023/dec/08/bomb-att...
So why anti-wcar? So in inner London, like 40% of households have a car but 90% of public space is roads. When u suggest that maybe the 60% deserve at least 20% of space for walking and cycling, you get labeleled anti car.
People complain about having like 8 coherent cycleways across all of london taking up too much road space, compared to thousands of roads. People complain about not being allowed to drive ancient diesel vehicles that kills kids eith astma.
Fine then, I am anti-car.
I am also anti-car, not anti-car everywhere but they just don't belong in cities.
Look at a map. Just zoom around the entire US, that isn't on the coast, and tell me how you're going to get rid of cars.
You decide on an inner-city answer to delivery and trash trucks, like maybe the robots that move pallets around in warehouses... You build easy ways for people to get in and out of their cars and trucks on the borders of those spaces... You stop letting cars and trucks on to main street. #bollards
Easy - make 'Light commercial' use of your house a constitutional right. There, all of USA fixed in one day. Now you can open a coffee shop in your garage, and it cannot be interfered with by zoning laws and mandatory parking minimums. And now your neighbours can sell pizza, and you can walk there and pick it up.
And if you have 2 days, allow apartments to be built withing 300 meters of any public transit.
Where are you from that you think this is feasible?
Britain people sell food from their house kitchen, on Deliveroo and Uber eats. Registration is really easy.
Obviously I meant that you build a real pizza oven in your garage, and park your car elsewhere
https://www.food.gov.uk/business-guidance/starting-a-food-bu...
A: Impractical. That's where your car goes. There's no where else to park it. Park it elsewhere, what?
B: Not suitable for serving food.
C: Completely ignoring the social norms of the area/culture.
D: It's not dense enough for that to make sense. People will have to drive there for the business to survive unless all 100 people living in that 1 mile radius eat pizza every day.
E: It's simply not big enough.
F: Therefore, weather. No one is walking to an outdoor garage pizza place with no seating in the winter. They're not driving either.
Look up Oshkosh, WI on Google maps and tell me where these customers are going to come from. There is enough commercial. There aren't enough people.
Most of the country is very sparsely populated. The 100k cities have kind of a city core, but they are spread out over 400 sq miles. The rest is nothingness.
Your idea requires completely resigning zoning laws against literally everyone's will, somehow adding parking for everyone's cars, and what, adding more busses that already don't get used?
Good.
Surely we aren't going to be hypocrites about it and designate political attacks on infrastructure as terrorism?
I think there's a perception too that before cars there were just horse and cart
When I look at old pictures of my local town there is a huge network of street trams, larger rail network than there is now
People used to have better public transport than they do now here and for much longer than most people assume
Stop making so much noise!
the loudest engine? a small literage non-turbo high compression motor of some sort.
the most famously loud race-car , the mazda 787b, had a 2.6 liter naturally aspirated motor. Small literage, small package, rotary. Fairly high compression. It deafened drivers.
turbochargers can be made to be annoying by enthusiasts, sure -- but that energy they produce is in large part thanks to the damping effect of the energy scavenging that they enable.
and as for engine size, as literage increases an engine developer has to do less to get the power they need -- that means they can use long and heavily dampened mufflers/exhaust systems, lower compression, lower RPM, less noise . Again, yes -- enthusiasts can ruin this, but the larger majority of these big motors are quieter/smoother than their counterparts that must go to extremes to meet the same power criteria.
That said, We don’t have to specify the means to reduce noise … just set the limit and let people comply how they want. But a large engine is a probably dead weight given the range of reasonable speeds in residential areas or off of a motorway.
That’s the thing - they are huge. Compare them to cars from the last few decades and the size increase epidemic becomes very clear.
What you might be referring to is the increase in choice of larger vehicles, or that weights have generally increased due to safety improvements. But the actual size of full size cars has certainly not gone up over the past few decades.
You can compare the older crown vic to the newer taurus. They are both full size cars. The newer taurus is about 100lbs heavier, 1-2" taller and wider, and about 10-11" shorter including a shorter wheelbase.
I highly doubt Tesla has any noticeably higher road noise than other full size cars. The tires are going to be the bigger culprit than weight/size if we're staying in the same size category (full size cars).
You might be right that people are choosing larger vehicles, but wouldn’t that mean the average size is increasing?
When you look at cars with a long lineage (eg Golf) they are huge compared to what they used to be, however maybe this varies region to region or it’s just my bias.
Look at Europe they have 80% motorcycles and otherwise small hatchbacks. Very very few large cars. That’s step one.
Acoustic bricks absorb sound, turning it into other energy. Commercial acoustic bricks example - https://www.randerstegl.com/en/wall-bricks/other-types-of-br...
So there is a Commons issue, why would I buy far more expense acoustic bricks when I can just reflect the sound, ie back at the cars.
Additionally bricks collecting stagnate water is very bad, and in a urban environment collecting dust and insects is bad.
Off topic but tress absorb a fair amount of noise and like Telsa's appreciate in value over time.
The problem (i think) is that the people (buyers?) may spend time in the area where the sound is reflected.