[bitsinthesky]

This is really cool. I was thinking the one biggest contributions to the feeling of public spaces being "not as nice" in the united states vs Germany/Europe is not the views or lack of money invested, but background car noise. You can hear the sound of a background highway almost everywhere in the USA, whereas the background world in for example Germany is much much quieter. And of all the ways cars make noise, I thought there was nothing to do about the sound of tires slapping the road.

The page points out the intent is to reduce tire noise in the cabin. I can see this being a marketing angle to sell it to the average driver, but will this mechanism lower tire noise for everyone or just the driver?

[szvsw]

> background car noise […] the sound of a background highway almost everywhere in the USA

To each their own I guess. Grew up in LA and the persistent thrum of the faraway highway at all hours of the night is a beautiful sound to me (but I also like/make experimental music so take that with a grain of salt).

I have so many fond but also sad memories of sitting on the roof alone at night on a relatively calm street, looking at the purple la sky (not a star to be seen) and just listening to the sound of the highways a few miles away. People often talk about how watching the stars makes you feel small but hearing the density of urban life in a way where it has just receded into a stochastic ever present hum is a wholly different way of feeling small… the life of the city goes on around you at all times, people zooming along in their cars completely oblivious to your existence and everyone else’s. All those individual discrete sonic events blending together, smearing out into a a single ambient rush. When you stay still and silent and listen for long enough that sound eventually becomes a roar to lose yourself in. When you eventually move and go back inside, climb through a window and shut it, the silence inside in turn becomes deafening and strange. Try it. Try to really listen to it.

[mitthrowaway2]

I'm curious about this as well. Often, structures that cancel waves by interference end up effectively redirecting those waves elsewhere, rather than destroying them altogether. But when it's very close to the source emitter, it is possible. Hopefully this doesn't just double the tire noise outside the car.

[bgoated01]

Resonators like this are effectively changing the resonating properties of the tire so that the vibration of the tire isn't as effectively changed into sound. Tires have certain frequencies or tones that they amplify, and the resonators can remove some of that amplication by redirecting the energy into the resonators themselves. It's equivalent roughly to adding a second pendulum to the bottom of a swinging pendulum. The first pendulum doesnt swing as far because energy is transferred into the second pendulum. The first pendulum being the one that effectively radiates noise (the tire), the final effect is less radiated sound. Since this treatment controls noise at its source, it will reduce noise for all parties.

Source: I worked on a resonator-based noise control solution as part of my Masters degree.

[luxuryballs]

for an electric car that could be a safety feature

[maxerickson]

My local park is pretty big and has a big jerkass contingent that likes to drive around in their poorly muffled vehicles.

A feature to make cars somewhat quieter isn't gonna do anything about that.

[dylan604]

Obviously comparing an apple and an orange isn't really that useful when doing direct comparisons. Making the car much more quiet for its occupants is not even in the same ballpark as what some jerkass contingent does to modify their car to make the world a less quiet place.

[hackernewds]

why is there no highway noise in Germany?

[lmpdev]

Not OP but when I was living there I noticed that major highways are generally physically separated from public spaces

I suspect due to better urban planning and less car-centric compromises on the placement of new motorways

Centre of towns and villages are more likely to be trams or trains than a highway. Very few settlements are anywhere near the autobahn.

Also the extreme emphasis on car maintenance was nice to see - polar opposite to where I’m from, Australia (similar I’d imagine to America). It seems that people here play a competition with who can illegally modify their car the most like cutting off catalytic converters and raising their SUV 4 inches for god knows why

[AmVess]

There is noise, it just isn't a loud as here in the US. Germany has vehicle noise emissions standards, including the tires. Further, Germany doesn't have nearly as many large trucks and SUV's, which typically have fairly loud tires.

[OptionOfT]

Different asphalt for example. Also less people with pickups and nubby tires.

[EdwardDiego]

Like their high speed train lines - 2m high concrete barriers to contain the noise. Also, they don't run highways through the centres of cities.

[euroderf]

Sound barriers along the highway don't have to be super high to be effective.