If you are a first-time visitor, I would like to wish you welcome to Elevating Sound – a site dedicated to the world of sound.
This is the first post in Elevating Sound’s newly launched Quiet Cars section – a section that will be dedicated to covering the ins and outs of quiet motoring and the quest to reduce cabin noise.
Quiet Cars – An Overlooked Need
Increasing numbers of car buyers are looking at noise as one of the key factors when looking for a new vehicle. Car manufacturers indeed have to take numerous aspects into consideration when designing a vehicle – safety, road handling etc – but it’s nevertheless astonishing that modern cars are not quieter than they currently are. The manufacturers have failed to recognize a sizable and growing market segment that highly values their car providing a quiet ride.
It seems to me that the automotive manufacturers and, even more so, the automotive journalists have put too much emphasis on sporty road handling, which have resulted in vehicles with stiffer chassis and suspension that deliver good handling when driving fast in steep curves, but as a downside, makes the cars too noisy.
The options are too few for drivers who love the idea of soft, smooth long-distance rides that make them feel fresh and relaxed upon arriving. Think the Bentley smoothness but in other price categories. There’s Lexus LS600h – perceived as the world’s quietest passenger vehicle – but it’s also out of reach to most people. Another quiet vehicle is the Mercedes-Benz S-Class.
There can be many different reasons for why someone has problems with too much noise inside the car. It can cause headaches, tiredness/fatigue, stress, irritation etc. And people with tinnitus, hyperacusis and other ear disorders may find driving a noisy car outright painful, forcing them to wear ear plugs or ear muffs to make it bearable.
When talking about noise in the cabin of the car, I am primarily referring to these three areas:
- Engine noise
- Road noise, i.e. the noise transferred into the car from the tires rolling on the road
- Wind noise
Besides these, you will have noise from other mechanical functions in the car, such as ventilation. And you may also hear different squeaks and rattles from the interior. But the focus here will be on engine, road and wind noise.
The subjectivity of noise
In order to assess the noise situation in the cabin, it is essential for you to test drive the cars you are interested. You need to get a feel for everything first hand, and not just listen to what others have said as to whether a car is noisy or not.
When it comes to sound and noise, it will be subjective in terms of how you actually experience it. The noise level in the cabin of the car can be measured in decibels (dB) which is an objective measurement of how loud it is.
But it will be insufficient for you to just look at the number of decibels, since that does not say anything about the frequencies of the noise at hand. People subjectively experience noise differently, since they react to high and low frequencies differently. When you test drive a car, you can both bring a decibel meter to measure the noise level (some meters will also include frequency) and you can, by listening with your own ears, conclude whether you react well to the nature of noise inside the car or not.
While there are no truly quiet cars below the luxury level, there are still a number of factors to take into consideration to help you out when seeking the quietest vehicle that meets your particular needs and budget.
The Essential Quiet Car Checklist
The Car
Do your own research on which car brands and models that are seen as quieter than others. As a general rule of thumb, larger vehicles are quieter than smaller. Some manufacturers will be attempting to position themselves as having quiet car models and you will be able to read about what noise-reducing measures they have taken in terms of the chassis, suspension, engines, windows, sound proofing in the doors etc.
The Car Platform
Many successful car models are long-lived and every so often, the model is overhauled through the launch of an entirely new platform/generation. In-between, throughout the lifecycle of a platform, there will be one or a few minor updates. The updates will in most cases have no impact on the noisiness in the cabin, but the noise level can vary considerably between different platforms/generations.
Hence, it is important to jot down the model year – and ideally also the platform name (or you can just ask about that at the car dealership) – if you read about a car being quiet so that you look at the right platform if you consider buying the car. As an example, the BMW 5 series has launched a new platform called F10 (Sedan) / F11 (Station Wagon) (2009-present), which is considered to be quieter than the previous platform, the E60/E61 (2003-2010).
The Car Type – Sedan vs. Station Wagon
As a general rule of thumb, Station Wagons are perceived as noisier than Sedans due to the acoustic resonance generated in the large open space at the back. However, most perceive the difference to be fairly small. If it’s important to you to bring down the noise as much as possible and you are ok with foregoing the extra space of a Station Wagon, then go for a test drive and see whether the Sedan is quieter.
The Car Type – SUVs, Trucks etc
SUVs, Trucks and other larger vehicles will – with their larger and higher surfaces – generate more wind noise. Depending on the type of windows and how well-isolated the doors are, you will get more or less of that wind noise transferred into the cabin.
The Chassis
Some vehicle models have a sportier configuration, often encompassing a sporty feel to the chassis by having it lowered. As a general rule of thumb, the sportier the vehicle is, the more road noise you will get inside the cabin. A stiffer, lowered chassis means more road noise when the road surface is a bit rough.
The Suspension
If you want a driving experience that is smooth with a car that does not transfer vibrations from the roughness of the road surface straight into the cabin, you should look for a softer suspension. Inquire about what kind of suspension is used and ask about its characteristics.
Again, it is important to test drive yourself. If you notice that road roughness is making the ride ‘hard’ and that almost none of it is ‘absorbed’ by the suspension, then it is probably quite stiff. Based on my experience, most modern cars seem to go with too stiff suspension. Maybe manufacturers believe that’s what consumers want, but I think it is sad that people who enjoy driving a car fast like a sports car down curvy roads have such an impact on the car market. There are lots of us who prefer an enjoyable motoring experience that is smooth and soft.
The Engine
It goes without saying that the electric engines are the quietest. Then comes the hybrids – i.e. the mix between electric and gas/petrol.
Historically, the diesel engines used to be very loud but the modern ones are substantially quieter and they are even quieter than gas/petrol engines when driving at highway speeds due to the fact that diesel engines work at lower revs. However, when driving at lower speeds, diesel engines are still audibly noisier than petrol/gas.
Besides the actual engine, it is the degree and nature of sound proofing that will impact the engine noise in the cabin. Go for a test drive to hear it for yourself.
The Windows
Some manufacturers offer laminated windows as standard or option. This feature constitutes layered glass in which the plastic laminate material provides an additional sound barrier, helping to reduce outside noise inside the cabin.
If you are unsure of the relative benefits of laminated windows, try test driving one car with and another without.
The Tires
The choice of tires is incredibly important. Merely changing tires on a car can really change the driving experience dramatically in terms of the level of road noise.
As a general rule of thumb, you get less road noise…
…the narrower the tires are
…the smaller the wheels are, e.g. 16-inch wheels are quieter than 18-inch – the reason being that the thicker the tire is in terms of height of rubber rolling on the road, the less noise will be created. 16-inch wheels will leave more room for a thicker tire than the 18-inch ones.
I will be going into explaining car tire sizes in detail in a later post.
It is also essential to note that the noise level of different tires with the exact same dimensions can vary substantially. This is due to tire manufacturers launching tire models with differing rubber contents – some tires are harder than others. Softer tires are generally quieter than harder.
Then the tire patterns also come into play – some patterns are noisier than others.
The European Union has launched a rating system in which tire manufacturers can submit decibel ratings of their tires (the number of decibels generated outside the car). I don’t know about elsewhere in the world, but I am sure similar systems exist or will be emerging.
I think this is great, but I have recently discovered that dB ratings from the manufacturers may not accurately mirror how they actually perform on the road. So it will be important for you to exchange experiences with other drivers, tire workshops etc to find out which tires that roll quietly in your particular surroundings (the road conditions and asphalt roughness/smoothness differs widely across the world).
Sound Proofing
Besides changing tires as a very effective measure to reduce cabin noise, you can also go about sound proofing your car by applying sound dampening/deadening materials throughout the vehicle. There are numerous companies that offer great solutions for this – two examples are HushMat and Dynamat. HushMat talks about creating a luxury ride in every car.
You basically install these materials by cutting out patches and sticking them to places like the firewall (the wall between the engine and the cabin), floor, doors, roof etc. If you feel uncomfortable about removing the inner door panels etc, then look for a local expert. However, many of the easier-to-get areas such as the floor and the boot, you can easily do yourself.
You can also treat the chassis and wheel acres with Tectyl (from Valvoline) or a similar product to prevent corrosion. As a by-product of that is claimed to be reduced road noise. However, Swedish automotive magazine Vi Bilägare conducted a detailed test of Tectyl treatment and the maximum difference measured between a treated and untreated vehicle was 0.7 decibels. So it does not seem to live up to its claims, but if you want to shave as much noise as possible, this could still be something to throw into the mix.
Please, comment below and share your experience of cars and noise. Is there an important parameter lacking from this checklist? Have you sound proofed your vehicle – how did it go?
And if you already own a quiet car that you are happy with, please recommend us your ‘optimal configuration’ based on the parameters above.
To learn more about cars and sound/noise, get your copy of the Quiet Cars eBook – Your Guide to a Quieter Ride – plus join the Quiet Cars online community.
Image: Nicholas_T
I don’t like road noise. It is annoying.
the quietest cars i’ve driven were a ’93 caddy de ville, and a ’17 chevy impala, esp. the latter. the caddy was a bit better at filtering out road noise, though.
This is a great post, I have a 2018 European spec Toyota CH-R with all weather Run on Flats and those are the worst tires I have ever heard in my life! I do remember in my previous car that I also had ROFs when I first got it and quickly switched to normal and the road noise was gone. Unfortunately, there are no normal all weather for this size. I guess I’m going to have to look for normal summer and winter tires for this car, hopefully they’re available. Also, the side mirrors generate a crazy amount of wind noise and I’m currently having a difficult time getting the dealer to fix it. They seem as confused as I am.
In terms of nvh, lexus gs300 is legendary. Just make sure they are wearing michelin preferably primacy 3st.
Every year car manufacturers have to increase gas mileage to keep consumers happy and buying. Since engines are at their peak of technology, they eliminate weight by making cars smaller, using more plastics, thinner metals, thinner windows and less noise deadening materials. Pretty soon we will be driving skateboards with cardboard cabins.
The wheel diameter has nothing to do with the sidewall height of the tire. Learn what your tire numbers mean.
It’s an old article but perhaps my experience can help a bit.
I am owner of a 2005 C 220 CDI which i believe is a great but noisy car. Not only the diesel engine makes a lot of noise but also road surface is very noticeable.
When you drive long trips you do not always want the radio at level 8.
So i decided to go for a sound proofing treatment. Not by a company but a DIM.
I bought Silent coat 4mm extra for sound deadening the metal parts and noise isolator 10 (some foam) on top of that. Combined with each other a very good noise blocker. It’s Self sticking stuff.
You have to calculate in M2 so in the end it is not a cheap solution and not for the faint at heart if you want to DIY.
I had to strip the car from its seats and sofa, mid console and carpet until bare metal. Also the back window shelf was removed. Perhaps taking the dash off would be better but this needs a lot of knowledge and also a lot lot lot work.
Applied 2 layers in total 14 mm at the bottom of the car, the back seat and the back window shelf. I took off the 4 door panels and did the same inside the doors.
Some people believe the roof should be done too but i did not.
I removed the plastic wheel arch covers above the wheels and add 4mm on the metal there too. The work took a couple of days. I did it in parts.
The result? Good. A much more quiet car. If you drive normal asphalt you hardly hear road noise. With the radio on at a normal volume you don’t hear you are driving.
With the radio off engine sound is noticeable but much less than before.
So don’t expect total silence. Biggest problem is low frequency sounds from engine and drive train. Low freqs are very hard to block.
The other week link are the car windows. There is not much you can do about them to block noise. Perhaps some foil but i have my doubts if such a solution works.
So unless you have the money for a Rolls a DIY with the right materials is a good alternative.
Good luck :-).
We have a 2009 Chevy Equinox. We love it except for the road noise! I have put undercoat in all the wheel wells, little help. I don’t know what level of noise we have but we can converse better on our motorcycle than inside the EQ.! I wear hearing aids and this type of sound is much worse because of them! We have Uniroyal Tiger Paw tires and I think they might be a big part of the problem but what brand would be quieter and is it worth paying 6-8 hundred $ for a little less noise? Are there companies that do soundproofing without changing the interior and exterior of the vehicle?
Great site! Now I don’t feel so alone…..
I have recently bought a 2009 Ford Mondeo XR5 Turbo (might be called a Fusion in the US – I’m in Australia) to replace my 2005 Mazda 6. The Mazda was beautifully quiet, but my Mondeo (which has luxury sport specs) has LOTS of road noise! The cabin itself is very quiet, with little wind, engine or traffic noise getting through….just the darn road! When I bought new Perreli tyres the tyre guy said it should be a lot quieter….but no.
So yes I can only put it down to the tyres being low profile (225, 45, R18).
I miss my quiet Mazda……
My old Rover 45 tdi was silent at any speed. It was the only car I loved. I have a Dacia Stepway and a Morgan now but the Stepway is great but noise is a strong factor. The Morgan well! no roof and speed hear nothing
Thanks for all engaging comments on this post! I’m excited to announce that I am about to launch an eBook about Quiet Cars accompanied by an exclusive Facebook-based online community. The community will be a great place for anyone interested in cars and sound/noise to share thoughts and insights with like-minded individuals worldwide. Get the eBook and join the community here: http://gum.co/quietcars
I would be willing to pay for access to a database of interior noise levels for affordable American passenger cars at different speeds, tires, and road surfaces. To the best of my knowledge, this information is simply unavailable to the public. Simply test driving a vehicle (for example, on asphalt) does not necessarily give you an accurate indication of how noisy it can really be on other road surfaces (such as concrete).
I read that for current cars if you clean firewall, inside doors, trunk & suv rear sidewalls and wheel wells- then apply 3M adhesive spray; acoustic foam (great stuff brand); trim with electric knife followed by 3M rubberized spray – you will get the quietest ride possible. That Dynamat stuff lowers vibrations but not much noise reduction. Foam absorbs noise and rubberized spray dampens sound and vibration.
Also, handling poor but interstate driving good. And gas mileage – believe it- has always been good at 18-25mpg.
The quietest best riding sedan is the Lincoln Towncar 1995-2011. Body style not great, but car is very comfortable and quiet. Unfortunately Lincoln forgot about quiet and ride with the new line of cars. That’s most likely the reason among others – sales have not been too good since 2012.
How does the Mercury Grand Marquis of the same years compare to the Lincoln?
Finally! People who actually “get” it. I just traded in my very noisy 2014 Honda Odyssey. It was so noisy at highway speeds – wind being the worst, then engine and tire. Others thought I was crazy, including my husband. He acknowledged the noise, it just didn’t bother him. I’ve always been hyper-sensitive to noise though. Professional reviews hailed the Odyssey for its quiet cabin. When I test drove it, the salesman talked the whole time and I never really got it over 65 mph, which is when the noise really starts. So the dilemma was, what to get next. I need a large seating capacity so my choices were rather limited without spending $60k on a Suburban or Yukon XL. We drove a 2015 Buick Enclave that was actually pretty quiet. I just hated everything else about it. Went with a 2015 Toyota Highlander XLE and I think (and hope and pray), it’s going to be ok. There is wind noise, but it’s a lot more muffled than the Honda was. I’m not noticing engine or tire noise. It just overall seems to be better insulated and can absorb noises better. At least with the Toyota, I can hear my kids in the 2nd row. I couldn’t in the Honda. Thanks for a very informative article! Makes me feel not so alone in my issues!
This is a poor excuse for an article, filled with BS. Did you do any research prior to writing, or simply write what came to mind?
Simply sticking hushmat on panels is not going to do anything? Why is that? Because it is the equivalent of using a hammer where you need a screwdriver. Hushmat and dynamat are sound dampeners. This means they are used to stop panels from vibrating, since the panel vibrating and the open spaces create a something like a speaker, which only creates more noise. This is only a small process of sound deadening a vehicle. Once you have stopped panels from vibrating, you must move on to actually blocking the remaining sound waves from entering the cabin, which you do with a barrier. You can either accomplish this like an idiot, by piling lots of layers of sound dampener on it and achieving horrible results, or you can do it the right way by using a real barrier: mass loaded vinyl. This is what is going to make a huge difference in the panels. There are several other steps, but it’s your job to write a proper article.
And like was mentioned by another posters, you have a huge weakness in the whole system: the windows. Unless you can source the same glass from a S500 or a L600h, you’re still going to have plenty of noise.
Now try again.
You sound like you might actually have something useful to add to this discussion. You apparently have knowledge in the area of noise reduction. So I wish you had stated it in a way that people could hear what you have to say and interact with you. That way others could learn from what you have to say.
Instead, the biggest impression you have left is of your huge deficit in the simple act of being a mature human being.
There are literally hundreds of sources that give you better information. DIYMobile has an abundance of posts on it, Sound Deadener Showdown has information and products that will work well, along with many other sources.
Rather than posting your petulant complaints about what I have to say about the article, you could be researching the subject like I did. It’s amazing what dedication of a bit of your time to doing a little research can do.
Thanks, I already started looking into “mass loaded vinyl” from your previous post. I will add DIYMobile and Sound Deadener Showdow to that. I’ve researched noise issues before over the last few years–that’s how I came across this site. But I also have a life to live, and this is not the only subject that I spend my time researching. You must be a fan of Moliere.
One issue with adding sound deadening materials to the cabin that I haven’t read anything about so far is the issue with toxic substances. I.e. how do these materials impact the air quality inside the cabin? Vinyl, asphalt etc are examples of materials that will likely release toxic chemical substances into the air.
Again, please provide specific links. And feel free to share your insights on how to block noise from entering the cabin. When reading some stuff on one of the sites you refer to, I also there find people discussing brands such as Dynamat. Plus one of the sites seem to partner up with a few given sound deadener brands which would make it difficult to understand whether the content is objective or whether it is skewed due to the partnerships. I would love to better understand which sound deadener materials and brands that really are the best ones.
Nick, the most noise-reducing windows I have ever experienced are the ones on the VW Phaeton, not S500 or LS600h.
You clearly underestimate that there is a need for a lot of car owners to learn about the basics in terms of what to think about when wanting to buy a production vehicle that is as quiet as possible. And understanding what can be achieved through different wheel sizes and tyre models is essential. I have spoken with numerous car sales men as well as leading automotive journalists and nobody has been able to lay out the basics as I have done in the post above. ‘Quiet’ is not something that the industry can deliver on despite the fact that there are a lot of people who value that.
My focus is clearly on regular, non-audiophile car owners who are not really looking to de-construct their car interiors to fill it with sound deadening materials. Having said that, I did include the last section on sound proofing and I agree on that I find that area the most complex. There are so many theories and opinions and sound deadening materials that it’s hard to navigate and understand which solution is the best without making the installation too advanced. You’d be welcome to write a guest post on how to best block sound waves from entering the cabin. And feel free to provide specific links which show before and after results in terms of sound treatments that you deem professional. I have provided a case study post on a treatment with Dynamat: https://elevatingsound.mystagingwebsite.com/how-to-significantly-reduce-road-noise-with-dynamat-noise-dampening-solutions/
If you find that to be a bunch of BS, then please help out by providing specific links to case studies that you see as more professional and credible.
Great site and great comments. We tried Dynamat in the doors of a 1998 Subaru Forester but it made no difference. The installer said doing the doors was the place to start for best results.
Currently, we’re looking for a small hatchback that is quiet. Our Honda Fit is perfect in every way except for noise.
Too bad the industry is trying to sell “sporty” handling when we all do our driving on a freeway going straight ahead or else we’re in town doing 20 in traffic. Neither requires good handling. People in BMW “ultimate driving machnines” are beside me doing the same thing. What a hoot! Their run-flat tires make them noisy besides.
I used to have a 1988 Mazda RX7 with 60 profile tires and it handled great. You don’t need 45 profile tires (noisy) for great handling. I think it’s an image or look people want these days.
I use a dB app on my smart phone to measuare cars I test drive. Even the Lexus CT200h I just drove was noisy. I know small cars and hatchbacks tend to be noisier, but that’s the type of car I’m after. May have to settle for a mid-size sedan.
This is a great article. Tires are the way to go. Actually this is the first and major thing. You’d be surprised in just swapping the tires how this can improve overall ride quality, and what yo uthinnk is bumpiness, is often misinterpreted as frustration dealing with excessive road noise. Let me put it this way, road noise makes the bumps twice as bad.
Thanks, Zeke! I agree that one can achieve a lot by exploring different wheel sizes and tire models. Which car do you drive and which tires have you found to provide the quietest ride?
In my opinion manufactures have desperately changed their material selections to satisfy governments demands for greater MPG. Evidence of this is in newer versions with the same motor get greater MPGs, but nothing revolutionary changed in the combustion engine that would warrant the higher MPGs. The key is they are using cheaper and lighter products so the car has less weight to move around, starting with the Windows! Just listening to the music play while I stand outside of my brand new bmw 5 series makes me feel like one hit on the window would make it shatter in thousands of pieces. If I sit in the car on the side of a highway the noise is really unacceptable for a $69k car. And I tried all the others (invarious models), Audi, lexus, mercedes, ford, honda, etc. and they are all the same, the only thing quieter would be a silverado truck, but a city slicker like me wouldn’t be seen driving one of those. I just think the large brands need to go back to the drawing board because this is ridiculous given the high prices for thier vehicles.
I tried BMW, lexus, toyota, ford. For some Reason the new Trucks like Dodge Ram, Chevy silverdo have the quietest cabin. car wise the the new Impala is good as well.
I realize this discussion was quite some time ago but I’m now just discovering it as I look for a quiet car. I’m a fellow tinnitus and hyperacusis sufferer and I’m really searching for the quietest possible car within my price range. I’ve done a lot of research and it seems like the Buick Verano has a lot of sound dampening built into it. Does anyone have any thoughts on this vehicle? Not sure if anyone even checks this thread but I thought I’d try.
Thanks,
Scottt
Scott,
I tried the Verano, for a small car yes it quiet but not that much different from a camry larger car. I would say go for the 2014 Chevy Impala. That one is quiet.
David
I wish i read this before i put 2k into Matting our our 2011 Honda Odyessy Mini Van. Made Zero difference! We have to have a Mini Van for 2 kids and 4 adults 2 stollers. There is no Van in America that will have a quiet cabin. I’m stuck with the noise.
I tried to convince the family to get a 2014 dodge ram truck crew cab, which i found to be supper quiet and can fit 6. No luck the wife refused to drive a big car.
How about filling the tire with the noise dampening material like the continental did? They patented a tire with a sponge filling which, I think, is simply not thick enough. The sound travels best through the air and there’s plenty of that in the tire. I think it would be worth experimenting with thicker and more sound deflecting materials. What do you think?
Hi Dag! It definitely seems worth it to experiment more with different tire solutions. I have yet to try the Continental ContiSilent tires so am not sure how well they deliver, but hopefully sound-absorbing foam can be a viable solution that makes a great difference. Have you seen these tires live?
For those not familiar with the Continental ContiSilent technology, check out this post: https://elevatingsound.mystagingwebsite.com/new-continental-contisilent-tire-technology-to-sharply-reduce-road-noise/
No, I did not. They’re available on only some models of audi but if they have achieved a 10 decibel reduction then it is a route worth exploring. I’m sure that better results can be achieved with better materials and different way of applying them. I know that most of the secondary road noise and vibration get inside the cabin through the chassis. The process is like this: tire hits the pavement -sound created – sound wave travels straight to the rim – vibration created – travels through the chassis as vibration – enters the cabin recreating the sound as there’s no sufficient buffers between the chassis and the cabin. I spent some time on this and have some ideas as to how this could be resolved without adding excessive additional cost or reducin the fuel economy but I’m very busy now and will experiment with this later. I’ve had a bad experience with a Buick lacrosse which was very well sound proofed except for the chassis related vibrations. I put additional sound proofing material into the wheel wells but that actually made the noise inside more unbearable. That’s when I realized that most of the tire noise gets in via the route as I described above. You can try to see what I’m talking about by takin the lacrosse on a rough cement pavement road. You’ll hear the regular tire sound which is very normal and not annoying and there will be as though an echo of that sound which is much louder and annoying – that’s the noise that comes through the chassis. If this route is not eliminated then It doesn’t matter how much soundproofing you do; you will be enclosed in the cabin with nothing but the road noise.
I’ve had the 2011 lacrosse. Now I drive a 2013 sonata and this one has less of that annoying secondary road noise inside; though, it still has some. That secondary road noise is always slightly delayed. If you listen well you’ll be able to detect the difference on just about any older pavement surface.
Thanks for the insights. I’m surprised that the Sonata has less road noise than the Lacrosse. Would you say the Sonata is also quieter overall or does the extra sound-proofing of the Buick make the Lacrosse a quieter ride despite the higher secondary road noise?
I fully agree with your reasoning about road noise. Unless you’re looking at developing some sort of patented solution, would you be interested in elaborating more on your thoughts via a guest post on this site? If so, and when you’re less busy, please feel free to send a text to hello@elevatingsound.com 🙂
Hi Magnus,
I do not see you discuss alignment: Is it because that falls under maintenance and not design? My 2009 Honda Civic Ex made a lot of noise which has gotten much worse these days. I am wondering this might be due to alignment. However I have heard that Hondas are louder due to their engine being 4-cylinder(?) ones.