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?
> 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.
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.
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.
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.
Okay, that's fine, the person I replied to was talking about removing road noise from the environment, so it seemed pertinent that lots of road noise is from vehicles that are in no way trying to reduce it.
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
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.
Maybe? It doesn't have a scale on the vertical, so you don't know how loud it is. It only shows that the horizontal bars are about 10dB. It's not a good chart. Essentially, somewhere just below 220Hz, it appear that there is a 10db dampening of the noise. We still don't know what that dampened level is though which makes this a meh chart at best
Since sound levels differ with distance and environment, absolute levels are not all that meaningful without a detailed explanation of their measurement setup. A 10dB reduction roughly corresponds to something sounding about half as loud to human perception.
I can see this point, but a 10db reduction from 90db to 80db is still really loud. A 10db reduction from 40db is even more impressive.
So having some baseline would still be helpful just to get some sort of reference. For science, you'd put the dampened wheels on a car and get readings from inside the car as that's the only thing relevant. You'd then replace the wheels with non-dampened versions on the exact same car, and then take your measurements from inside the car again.
This isn't rocket science. It doesn't need to be any more complicated than taking readings where your target audience will be sitting. The fact that this even needs to be stated explicitly just makes me sad for common sense
I mean, we’re talking half as loud. I would have thought to a layman it would be a lot more impressive to remove half of a loud sound than half of a quiet one. But I’m wrong on that one judging by your comment, which is fine. To a noise control engineer whether the sound is loud or quiet makes no difference to how impressive it is because these are linear systems (unless we are talking extremely loud e.g. >140dB). Good point on the obvious measurement location.
If I offer you half of a pie, you might think I'm being generous. If I then tell you the pie is actually only 5cm in diameter, you'd be disappointed. Receiving half of a pie that is 30cm would be much more impressive.
Telling me you removed half of something with out telling me the size of the something isn't compelling.
Yeah, I guess the reason we're talking past each other here is I'm thinking of the tool; if I gave you a coin that would purchase half of any pie then the pie size is irrelevant. Put this tire on a different road and the absolute sound levels will change, but the sound difference with and without the treatment will not.
Literally reading this as we are driving up I5 in a 2019 Honda, and I'm hearing a ton of tire noise right now. Haven't done this drive in a different car recently, so can't compare, but it seems to be a "normal" amount of road noise.
I peruse the Apple Watch subreddits from time to time. A lot of the posts are pictures of people’s watches on their wrist (yeah, I don’t know why, either). But here’s the relevant part: I’d bet a good 80% of the pictures are selfies taken with the poster sitting in the driver’s seat, and few are sitting in a parking lot.
NVH is a big contributor to perception of quality in the car world. This is a very elegant solution to a problem that probably wasn't all that high on the list.
Helmholtz chambers are found on loads of off-the-shelf aftermarket exhausts nowadays (and some OEM ones) - they aren't complex/expensive to manufacture, making them an easy option to tune the exhaust sound of a car. Super common in the muffler kits offered for things like civics, miatas etc to try and get a more exciting note out of a four cylinder.
Conveniently, they left out how much mass first- and second-generation resonators weigh per wheel and their center of mass radius (distance) from the axis of rotation. This would be crucial to determine if cabin floor-mounted ANC speakers, mics, and a controller would/n't be cheaper to haul around than adding additional rotational inertia to the wheels. Surely, it's cheaper for manufacturing and simpler, but it doesn't necessarily translate into being the cheapest TCO solution for the buyer.
I wonder how much these "resonators" are tuned to a specific tire and even tire pressure?
Are they going to make the noise worse if you get the wrong replacement tire that has a different rubber compound or sidewall stiffness? If you under or overinflated your tires?
> As the tire size is known, pipe resonance frequency can be determined. By generating sound that cancels out that frequency, pipe resonance can be suppressed.
Recently spent quite a bit of money on bridgestone's "quiet" tires and it didn't do shit. Hope this is more effective, it would definitely influence my purchasing decision for my next vehicle.
You got Bose'd.* Tires aren't going to do much unless they were designed for your specific rims on your specific vehicle, which is what Honda does. But without also adding Helmholtz resonators designed for your exact wheels and tires, or an ANC system, you'd need 100+ lbs. of mass-loaded vinyl applied to the doors and underbody to measurably soak up road noise. It's doubtful tire pattern can even come close to approximating active or passive designed NC, but it probably can be made much worse with certain tire/tread designs that induce resonance.
Not really. Go stand next to a highway sometime: the vast majority of the noise you're hearing is from tires, not engines. You'll notice the engine noise occasionally: it'll be from some moron who's modified their exhaust to be louder usually. With all the other cars, you're just hearing tire noise.
You are correct.
“Karl Fundkvist, a design engineer at Goodyear who specializes in acoustics.
At low speeds, the engine and exhaust system are the primary sources of noise, but at about 35 mph tire noise comes into play. At freeway speeds, the tires account for about 60% of the noise a typical car makes, Fundkvist said.”
They're not, you're not. As my comment (nor the sentence in question) was obviously not referring to the noise heard by others, but rather by people _in_ the car.
My last two cars have had acoustic/noise dampening to the point where one of them (Audi) even pumps engine noise into the cabin at a low level (and it's not a particularly quiet engine - twin turboed 2.9L V6).
I realized long ago that when I travel in my Grand Caravan on cruise control at 100kph I mostly hear tires. Engine noise is not audible unless the engine goes high RPM when going up steep hill or whatever other reason
They likely have the same 4x100 bolt pattern… find out what models have the noise cancelling and order a set from the dealer once you confirm the bolt pattern and that they are a similar tire size.
Edit:
CRV has a different bolt pattern. 5x114.3 instead of 5x100. You’ll have to use an adapter or get a 2022 Prius which should have the same bolt pattern, could also swap the wheel hub to 5x114.3
You could also go to a wheel shop, they often have stock wheels from people who bought aftermarket. If you’re not a car guy just go to a wheel shop they should be able to do the swap for you, all Toyotas are parts bin cars, so everything is pretty interchangeable.
maybe it's just me, but putting something called an adapter on the wheels of my car bought from a link on ebay just doesn't give me a warm and fuzzy feeling about any of it.
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?