By on February 8, 2009

Rolls-Royce used to advertise the fact that their cars were so quiet that the loudest sound you heard was the [analog] clock ticking on the dash. Who said the British don’t do hyperbole? As a quiet car connoisseur, I’d have to say a Clinton-era Cadillac provided the quietest ride I’d ever experienced; if the time was one of peace and prosperity, then so was the car. Nowadays, automakers are telling us that their cars are quiet, or at least quieter than ever before. I’m not buying it. A number of recent drives have been notable for their aural uncouthness. So I set out to find the truth about automotive sonic signatures. Has nostalgia dimmed my memory (if not my hearing)? Is progress on the noise suppression front been less impressive than industry propaganda would have you believe?

The German buff book Auto, Motor und Sport recently opened its archives to tightwads. I’ve spent a few hours perusing the decibel stats. To save space, the table I’ve compiled only deals with interior noise at about 80 mph (130 km/h). It’s a civilized speed (at least here in Germany) at which one would want to be able to hold a civilized conversation, even with a back-seat passenger.

Car and model year Interior noise in dB(A) at 80.78 MPH

1995 BMW 728i 66

1995 BMW 523i 66

2003 BMW 730i 66

2009 BMW 330d 68

2009 Mercedes C350 CGI 68

2009 Renault Megane dCI 69

1996 Mercedes C280 69

2008 Mercedes C250 CDI 69

1996 Citroen XM V6 69

1995 Audi A6 2.8 69

2006 Mercedes E220 CDI 69

2006 BMW 520d 69

2000 Ford Mondeo 2.016V 69

2009 Ford Mondeo 2.5 Titanium S 70

2006 Audi A6 2.7 TDI 70

1996 Mercedes E230 T 71

2003 Toyota Camry 2.2 71

2009 Toyota Auris 2.0 D-4D 71

1995 Honda Civic 1.5i VTEC-E 72

2009 Honda Civic 2.2i-CTDi 72

2002 VW Golf 1.9 TDI 72

2009 VW Golf 2.0 TDI 72

2009 Opel Astra 1.9 CDTi 72

1996 Opel Astra 1.6 16V 73

2003 Toyota Corolla Compact 1.4 73

2009 Porsche Carrera 73

1995 VW Golf Cabrio 1.9TDI 73

1996 Ford Mondeo 1.8GT 73

1995 VW Golf CL 1.6 74

1995 Mercedes E230 74

2000 Toyota Corolla 1.6 76

2009 Ford Ka 76

1996 Renault Megane 2.0 16v 76

In some market segments (e.g., executive cars), you have to ask: where’s the progress? What, for instance, has BMW been doing since 1995? Most cars have gotten much heavier. You think that the extra heft might include some extra soundproofing. But plenty of today;s lumbering leviathans are hardly quieter than their sprightlier predecessors. What does Mercedes expect us to think about zero improvement for the C-Class in twelve years?

VW’s press release for its newest Golf calls it “the quietest Volkswagen Golf since the model series began” characterized by “first-class acoustic properties.” Yes, “a special sound-damping film in the windshield reduces driving noises, as does the newly developed seal design on the doors and side window guides.”

Significantly less wind noise is generated by the outside mirrors due to their new shape. Furthermore, special modifications were made to better isolate the engine and passenger compartments from one another acoustically. Quiet rolling tires and new engine bearings round out the noise reduction program.

Empirically, the new Golf offers an improvement of 2 dB in three car generations and thirteen years.

Small cars have gotten much better, though. Corollas and Renaults used to be noisy boxes. Intense competition in the compact field seems to be working its magic. The Auris (the more-advanced, Euro-market Corolla) is a quite soothing small car, and the Megane’s low level of noise is a marvel.

Really small cars, like the Fiat Panda or the Ford Ka, are still noisy, and are thus for me un-purchasable vehicles, since they (driven quickly) generate a clamor louder than Occupational Noise Exposure standards would allow.

A noise level of 70 dB(A) seems to be hard to crack in cars for regular folks. But this is, to my mind, a pretty tolerable loudness, unreachable a few decades ago.

You’d think with advanced computer firepower, more precise manufacturing tolerances, double-lip door seals and multi-laminate windows, cars would generally be much quieter than in the 1990s. Why aren’t they? Remember one dirty secret of the car industry: usually, each successive generation of a car is cheaper to manufacture. Cost-cutting means that progress is slow—unless the market actively demands progress.

Or unless the car maker is genuinely forward-thinking. In terms of quietness, the only revolutionary car in recent years may be the Lexus LS 600h, which claims 60db at 60MPH.

On the other hand, where are the technical advancements we’ve been waiting for? Active noise cancellation, once seen as the answer to all things cacophonous and found in Honda’s cylinder de-activating Odyssey minivan, seems to be a pipe dream. This despite the fact that BOSE et al. have been promoting its benefits for years, and Germany’s Fraunhofer Institute says it’s working on a useful system.

And what about a microphone-based, user-friendly and effective interior intercom? I’m tired of shouting at back-seat passengers (although it can be useful in the case of children, dogs and back-seat drivers). A car that used electronics to help you converse with everybody on board, without raising your voice: now, that’s something that would lead me to a showroom, and to ponder a purchase.

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67 Comments on “The Art of Noise...”


  • avatar

    The only true way to measure noise is with a sound meter in decibels.

    I always felt my Ford Expedition rode quietly and you could barely hear the engine.

    Then my Chrysler 300 – I hear tire/road noise but the engine is quiet.

    In my S550 its very quiet till you step on it hard and then you hear roaring.

    I rode in an LS460 and it was less quiet then my Benz. But many magazines state it is quieter.

    quietness is subjective.

  • avatar
    DweezilSFV

    It’s the same peeve I have. I grew up in the “Quieter Than A Rolls Royce” Ford era. We had a 66 Mercury that I thought was the penultimate in quiet. [Quieter than a Ford that is quieter than a Rolls Royce ?? Yes, there was a time when Ford at least made a stab at making Mercury a \"better\" car for the price].

    Car & Driver in the 70s used to publish lists of road tests they had done during the year and included sound level readings. One year among the most quiet was a Buick Century at 69 dBA @ 70 mph cruising. Don’t know what that would have been at 80. In the full road tests they’d give cruise, full throttle and idle readings.

    With the constant background noise everywhere and living in LA, I want an isolation tank on the commute and proper sound deadening is important. I wsih they’d still offer extra insulation packages.

    But it is subjective. I like hearing the engine, but don’t want to hear the suspension making any noise over bumps, or wind & road noise.

    Some people like less sound suppression and feel more connected to the road without it, or enjoy the other sounds.

    Once the rags stopped posting the dBAs and testing for gas mileage rather than just posting EPA #s [or at least had when I stopped], I gave up on them. Most of the tests in them now are like expanded “thumb nail” reviews, so the Internet has my eye instead. [And especially TTAC...]

  • avatar
    Viceroy_Fizzlebottom

    When I sat in the XJ8 last year at the Chicago Auto Show the first thing I noticed was how well it blocked out the sound of someone’s wild kids running around the car

  • avatar
    FrustratedConsumer

    “The newest Golf is reported to be exceptionally quiet. The numbers belie this statement: an improvement of 2 dB in three car generations and thirteen years? How weak is that?”

    It’s not weak when you start off (as your table shows) with a car that is already exceptionally quiet.

    I was growing tired of my ’03 GTI so I took some test drives of newer cars. The very first thing I noticed is how much noisier other, newer more expensive sedans are. I also tried out a newer Mazda3 which is very similar in driving dynamic but the noise (particularly engine) was very intrusive. I decided to keep my ’03 since anything else I could afford was far more noisy.

  • avatar
    Gardiner Westbound

    Road noise is the primary culprit in our Acura 3.5RL, a car with a jewel-like engine that idles at 250 RPM. Some roads are much noisier than others.

  • avatar
    John Horner

    “Road noise is the primary culprit in our Acura 3.5RL”

    Poor road noise isolation is the Achilles heal of every Honda/Acura product. As much as I like my ’06 TSX, there are some pavement surfaces over which it is absolutely painful to drive. Several hours on highway 290 through West Texas almost blew my ears out.

  • avatar

    Cars ARE much quieter than they were a decade ago.

    Tires are much noisier.

    The Bimmers of fifteen years ago ran on 195-width, 65-series Michelin X radials; today’s equivalent might run 245s and 30-series.

    Currently, during Euro “drive-by testing”, in almost all cases the noisiest part of the car is the rubber.

    The answer is just as simple as that. And the reason the “sound gap” has diminished between luxury cars and regular vehicles is just as simple: “regular cars” still roll on quiet, relatively narrow tires.

  • avatar

    Interesting article, Martin, quietness is something that I’m always trying to find numbers for in my various car researches, but you can never find posted dB levels anywhere. It’s very frustrating. For instance, I would very much like to compare the dB at speed in, say, the Corolla, Civic, Focus, Mazda3, Cobalt, Impreza, Elantra, etc. but nobody that I’ve found on line posts the numbers. I guess it isn’t that important to people, but an isolated ride is pretty important to me on a 7 hour drive.

  • avatar
    Davekaybsc

    It’s all in the tires. OEM tires are almost universally bad, and some of them scream and roar over anything less than pristine pavement.

    For the new RL, Honda claimed that they were able to use thinner glass because of the active noise cancellation system. In reality, they just made the car noisier than ever. The RL is one of the loudest so called luxury cars I’ve driven. And one of the worst.

  • avatar
    KatiePuckrik

    At the risk sounding like a fangirl, I’m extremely surprised that there are no Jaguars in that list. One of Jaguar’s core value is quiet ride. I drove a new XJ and couldn’t believe how serene the drive was.

    Not quite sure how the experience would have been if the car had a diesel engine, but I hear, Jaguar’s diesel powertrains are very good….

  • avatar
    Usta Bee

    Do modern cars come with “undercoating” anymore ?. The only places I’ve seen it sprayed on newer cars is in the wheelwells.

    I went from a 1992 Acheiva to a 2002 Prizm and the Prizm is a MUCH noisier car on the highway. Most of the problem is the undergeared 3-speed auto that makes the engine roar at anything above 60mph. It doesn’t really matter as I usually have the stereo cranked up to the point where I can’t hear the car. My car stereo is a special one, I got it because it goes to “11″.

  • avatar

    2 db is a significant drop. 1 db is double the noise level, it’s an exponential scale. I have a stereo that has a “mute” button. It drops the noise level 20 db. You go from ear-splitting loud to just barely audible with that button. The volume knob has db measurements, 2 db is one notch, and it’s the difference between conversation and shouting.

  • avatar
    romanjetfighter

    Tire noise is something that really bothers me on long trips. I think tire choice has alot to do with the nose in the economy cars, fitted with cheaper tires. That’s my theory.

    Cars haven’t gotten that much quieter, IMHO. 2004 XK Convertible is only slightly louder than 1996 V6 Camry, which has slight more engine and tire roar than the 2009 I4 version.

    Quietest car I’ve experienced was in 1998 when we got our new Sienna. It didn’t have ANY noise at idle. We’d be confused to whether it was on or off sometimes and my dad would have to look at the tachometer. :P

    As far as comfort on long trips, noise is more important than a floaty ride.

  • avatar
    BDB

    “Car & Driver in the 70s used to publish lists of road tests they had done during the year and included sound level readings. One year among the most quiet was a Buick Century at 69 dBA @ 70 mph cruising.”

    Buicks do tend to have very quiet rides.

    The 1993 Park Avenue Ultra my grandparents had was ridiculously quiet–you could be going 75 mph on the freeway and hardly notice! Like a living room on wheels.

  • avatar
    BuzzDog

    I’m not convinced that dB(A) is the ultimate measure of quietness.

    Without getting too subjective, the various frequencies of sound heard in a vehicle should no doubt make a difference in the occupants’ perceptions of noise.

    It’s very possible, for example, that we’ve traded the high-pitched wind noise of pre-1980s vehicles for today’s low-pitched hum of the tires. When measured, overall sound levels may be equal; however, the casual listener tunes out the low-frequency sound and thus “feels” that the vehicle is quieter.

  • avatar
    findude

    Many newer cars seem to have had their exhaust “tuned” to be louder and make the car seem more powerful. The noisiness is sometimes designed as a feature.

    Noise strikes me more as a product of inefficiency or poor engineering than as a virtue. I remember seeing a large group of 1950s and 1960s Mercedes-Benz 300SLs (gull wing coupes and roadsters) doing laps at Laguna Seca during the historical auto races. They were almost silent compared to the very noisy Corvettes and Cobras that ran in later laps. Their designers made choices.

    • 0 avatar
      The Black Stig

      I would like to say that the reason for that is that the 300SL’s were Turbo, Any car prefomance turbo car will be quieter (engine wise) than an equal preforming N/a car

  • avatar
    Brock_Landers

    Some time ago Swedish car magazine also tested db levels:

    http://www.vibilagare.se/zino.aspx?articleID=12579

    10-bästalistan

    Lexus LS 600h 65,9 dBA
    Mercedes S-klass 68,7
    BMW 5-serie 69,1
    Volvo V70 69,5
    Renault Mègane 69,6
    Audi A6 69,9
    Volvo S80 70,6
    VW Tiguan 70,7
    Toyota Prius 71,3
    VW Passat 71,4

    10-sämstalistan

    Citroën C1 77,4
    Nissan 350Z 76,8
    Ford Focus/Opel Astra 75,2
    Skoda Fabia 74,5
    Toyota Auris 74,4
    Skoda Octavia 74,1
    Kia Cee´d 5d 74,0
    VW Golf 73,9
    Kia Cee´d SW 73,8
    Peugeot 308 73,7

  • avatar
    MagMax

    Road noise (and suspension harshness) did it for me after I’d stupidly traded my lovely Acura Legend Coupe for a Vigor sedan–I thought I needed 4 doors. That Vigor was terrible on some highway surfaces and when it went over a bridge expansion strip it was like sitting inside a Jamaican steel band drum. I got rid of it after a bit more than a year for a new Maxima that was much quieter, with a much more absorbent ride too. My E500 is very quiet most of the time except on acceleration. Most of the non-engine noise in today’s cars seems to come from the tires and in models with folding rear seats there seems to be even more noise, especially when driving in rain. I had a 2000 Maxima that was terrible as soon as the wheels were throwing water up into the wheelwells. I recently test drove a new Maxima that was also very quiet until I pressed down on the accelerator: that engine noise sure came through loud and clear. But none of these comes close to the racket my old 62 VW made full out on the highway, narrow tires or not.

  • avatar
    CarPerson

    Remember the ads sometime back where a Lexus(?) was at a waterfall with birds singing? The door was then closed to portray a totally silent environment? As If. On worn pavement, 2007 Accord is intolerably noisy.

    The more worn asphalt becomes, the more noisy it is. I put on a set of Pirelli P-Zero Neros (noted for being quiet) and at first it really helped but at 50% tread wear, it’s back to noisy.

    I wear earplugs to and from work because of the road/tire noise and the horrible auto trans gear whine. Chrysler dealer will not fix the whine in my “remanufactured” transmission that is pouring oil out the tailshaft and cannot find “D” for about 10 seconds after backing it out of the garage.

    They claim Chrysler has all but abandoned warranties and they’d just end up eating it.

  • avatar
    Bill Wade

    They claim Chrysler has all but abandoned warranties and they’d just end up eating it.

    Good topic for a Chrysler Deathwatch.

  • avatar

    It should be noted, as Carperson mentions, that tire choice is important to minimizing noise. A good set of tires will reduce roar by a significant amount. My father put some Toyo luxury tires on his G35 and the difference in noise was impressive (the complete lack of wet weather grip was not).

  • avatar
    davey49

    Consumer Reports doesn’t list db numbers anymore in its road tests. they said the numbers don’t tell the whole story because some noise is easier to take than others.
    My Saturn is loud.

  • avatar
    esldude

    I too find the Clinton-era large Caddy’s the quietest I have ridden in though I don’t have lots of seat time in expensive Euro sedans. I have ridden in two custom cars that were quieter still for the most part. They were coated in many areas with sound damping material and had all hidden spaces filled with insulation of some sort. These were older cars that still had some wind noise at speed.

    I see how the idea of only sound level measures count. On the other hand it isn’t quite true. What you really need is the picture by frequency as well. Simple fact: we are more sensitive to some frequencies than others. So a single wide band number that is the same in two cars can still seem noticeably quieter in one car vs the other when the frequency distribution of that noise is different.

    A-weighting which is sited by most is a partial solution to that. Even then however, a car with a huge peak in the wrong place can seem noisier than the dBa would suggest of if in a different place it can seem quieter than you would expect.

    I think wind noise is mostly handled well today in cars. Tires can be a problem and still the drivetrain excites much of the noise you hear. In most mid-level and lower cars try throwing the car in neutral at 70 or 80 mph (130 kph). You will find you are left with a bit of tire noise and maybe wind whooshing. But a noticeably quieter ride with the engine just idling.

  • avatar
    dean

    JEC: I think you meant to say that 10dB represents twice (or half) the sound pressure. Regardless, your point that 2dB represents a not-insignificant reduction is valid.

    You want loud, go for a spin at 60mph in my Suzuki Sidekick! Or experience the ear-splitting wind noise on a motorcycle at a sustained 90mph without earplugs! (I always wear them on the highway.)

  • avatar
    red60r

    Another company’s ad, contemporary with Rolls’ silence claim, said: “At 60 mph, the loudest sound in a Land Rover is the roar of the engine.”

  • avatar
    Paul Niedermeyer

    I wonder if these dB numbers are really comparable, if they weren’t all driven on similar pavement, which varies a lot in the sound it generates. A stretch of connector freeway was repaved here recently with special low-sound generating pavement, and it’s quite remarkable the difference it makes.

    On the other hand, the grooves cut into older asphalt by spiked tires (still allowed here in Oregon) are extremely noisy.

  • avatar
    Greg Locock

    A doubling of sound power is 3 dB, not 1 dB. Typically people can pick a loudness change of somewhere around 1-3 dB in proper tests where there is a time interval between the two levels, as opposed to when you just turn the volume knob up a bit.

    dBA weighting does not correlate very well with a subjective impression of noise across different car types – that is, it gets quieter as you make a particular car quieter, but two cars with the same dBA in a given condition can sound 1 or 2 ratings different on a 1-10 scale. So comparing dBA between different models can be very misleading.

    At 80 mph in the old days you were measuring windnoise and a bit of engine noise, these days most of the dBA number would be a mix of windnoise and what I will loosely call tread roar from the tires.

    The original Lexus 400 was the only car I have ever driven that was reasonably quiet in most conditions.

    Fixing NVH requires gobs of time, money, engineering, prototypes and weight. Not many companies are inclined to chase it down much below the competition for that reason.

    Antinoise is a bit of a red herring, it solves problems that are cheaper to fix by conventional means. It may be lighter than conventional means. Bose have never demonstrated ANC in a vehicle have they? Did they show the measured benefit?

  • avatar
    Martin Schwoerer

    Interesting questions and comments, interesting discussion.

    On tire noise: yes, tires are a major problem. But I do think the manufacturers could deal with it if they wanted to. BMW for one inexplicably installs runflats that are both hard and noisy. This has been criticized by other authors at TTAC repeatedly. And in general, I see no principle reason why a larger contact patch must be louder.

    The subject of tire noise as an *environmental* problem has been touched by TTAC at http://www.thetruthaboutcars.com/eu-retreads-tire-labels , and is a pet peeve of greenies such as the European Federation for Transport and Environment, as I could mention. Such parties say tires could be *a lot* quieter if the industry wanted it.

    On the Golf being 2 dB(A) quieter now than in the 1990s: yes, the scale is exponential. But no, 72 dB(A) is not particularly good. I suspect that most of this car’s improvement is in the low-speed spectrum. Not without reason was the Mk6 presented to the press in Iceland.

    Katie: I strived to supply historically comparable data. None on Jag to be found. But here’s a tidbit: 2003 Jaguar XJ6 3.2: 67 dB(A) at 130 km/h.

    Brock: at which speed were your interesting numbers recorded?

    On the subjectivity of decibel measurements: sure, that’s where science touches art. Some cars sounds annoying and intrusive, while others no quieter sound sweet. At a given noise level I’ll take an Alfa, a Subaru or a Porsche any day. I never understood why anybody would buy a Viper that sounds like a clogged vacuum cleaner, or a Jaguar XJ220 that sounds like a bucket of nails. But that’s just me — and it’s also the topic of another editorial. My humble 800 word contribution is just about the low level of historical progress in some market segments.

  • avatar
    yankinwaoz

    I dunno. You need a little road/motor noise to mask those irritating plastic-on-plastic squeaks from parts buried deep in the dash. My Volvo sounds like a Lakers game when I drive…. “squeak,squeak,squeak”. Drives me nuts.

    I’m curious if any ambulance drivers can contribute their observations about drivers who can no longer hear sirens thanks to the excellent noise protection of their luxury cars.

  • avatar

    As the title implies, there’s an art to noise. Manufacturers have learned that simply reducing common sources of noise serves to make less pleasant noises much more obvious. So what you want as much as an absolute low noise level is a pleasant blend of the noises that do make it through.

    No one enjoys tire noise, or rattles and squeaks.

  • avatar
    zenith

    I used to think that tachometers in automatic trans. cars were an affectation until I got the Aztek.

    I usually don’t know that the engine is idling without consulting the tach.

    The day we got it, the lot attendant brought it off the wash rack and I thought he’d shut it off since it was so quiet. Since the starter won’t run if the engine is running (the first car I’ve ever had with that feature), I didn’t even have the sickening grind to tell me it was still idling.

    I kept turning the key, hearing nothing, and wondering about a car that was giving me such trouble before even pulling out of the lot. Then, I glanced at the tach…DUH!!!

    I get more noise –and it’s still not much– from the HVAC fan on #4 setting, than from the engine.

    My Ranger isn’t silent, but it is much-improved over various ’70s and ’80s F-Series trucks I’ve owned in the past.

  • avatar
    levi

    KatiePuckrik : …but I hear, Jaguar’s diesel powertrains are very good….

    An appropriate comment if I ever heard one.

  • avatar

    But I do think the manufacturers could deal with it if they wanted to. BMW for one inexplicably installs runflats that are both hard and noisy. This has been criticized by other authors at TTAC repeatedly. And in general, I see no principle reason why a larger contact patch must be louder.

    BMW has a solid reason for installing run-flat tires: they save lives, protect unskilled drivers from themselves, and remove the need for a spare tire. These are more compelling reasons than the arguments against RF tires, and that’s why they do it. I don’t like it myself, but I’m not likely to kill my family if I lose tire pressure on the freeway, whereas many people would do just that.

    It would take more than 800 words to discuss why tires generate noise, but it many ways it relates to simple physics.

    Grip is a factor of friction. Rolling resistance is a factor of friction. Friction means energy loss. Energy loss creates vibration, and it creates heat, which is also vibration. Vibration creates noise.

    Low-rolling-resistance tires are quiet and gripless. Hoosier R6es are louder than piston-engined airplanes. Most tires are in-between.

  • avatar

    WHAT??

    –chuck

  • avatar
    BuzzDog

    I also wonder if the move to leather interiors is somehow responsible for higher dB(A) readings in vehicles of more recent vintage.

    The cloth and velour interiors of yesterday may no longer be in style, but you’ve got to admit that the soft surfaces were better at absorbing sound waves.

  • avatar
    robertplattbell

    “The only true way to measure noise is with a sound meter in decibels.”

    While this may quantify noise, noise can be a subjective thing.

    Some of these cars may read “quieter” than others on the dB meter, but if your rode in them, your subjective opinion may differ.

    Some sounds are unobtrusive, even when relatively loud, while others are annoying, even if relatively quiet.

    A low rumbling exhaust may be louder, but sound pleasant to the user. A wind whistle, or worse yet, a rattle, jars the brain.

    dB is a good place to start and good for quantifying. But it is hardly the end-all in noise evaluation.

  • avatar
    jerseydevil

    i have a new Cadillac DTS at work. Its really quiet. I have a VW Golf 3, its kinda noisy, but its 13 years old.

    I really like quiet cars.

  • avatar

    Recently,I bought a new set of tires for my Mazda3, 205/50/17, the original tires, Good Year RSA, were so loud it was simply impossible to speak to a back seat passenger without screaming even at 65 MPH, so I was looking for a tire that will be at least somewhat quieter, this is no easy task, nobody give this information and reading reviews by other people makes it even harder.
    At the end, I understood that tires with such short sidewall must make some noise, I did not understand why do I need V rated tires that can go up to 149 MPH, the car max speed is 118! this alone probably contribute a lot to that noise they are making.
    I got the Dunlop sp sport signature, they might be less noisy, not sure about it, but at least the ride is much smoother.

  • avatar
    willbodine

    You cannot make a valid judgement on a given car’s noise level by the dba value. And 2 cars with identical dba scores can have very different noise patterns on the road.
    There are basically three kinds of vehicle noise:
    engine/exhaust, wind, and road (texture) noise. To me, road noise is the most offensive, especially on long trips. These days, most makers have wind noise licked, and most are good with engine/exhaust. It is the road rumble that has not improved; I would argue that it has actually gotten worse. Blame hard bushings and sport tires. Of the top 3 Germans, I rate BMW superior because they attenuate all 3 noise sources to similar levels; no one type predominates (even with the run-flats.) In a current 5 or 7 Series the overall effect is one of muted white noise. And the Rolls Phantom (a BMW) is in a league of its own. I couldn’t believe that a moving vehicle could ever be that quiet.

  • avatar
    fincar1

    I agree with the posters above that Hondas are worse than most cars for road/tire noise. I can’t help but wonder if that was a factor in why the 90′s Accord wagons didn’t sell better; with a much larger interior volume to boom the tire noise, they may have been pretty bad. And of course when the tire tread gets thin the noise is even worse.

    My 03 Chevy regular cab pickup is as quiet as a friend’s 03 DTS Cadillac. If it didn’t ride like a truck it’d be a nicer trip vehicle than the 99 Accord. It’s nice for Silverado drivers that GM sells $40,000 suv’s with the same design; the pickups gain in many ways from that – quieter inside, nicer controls and switches, better finish.

    My 76 Cheyenne regular cab pickup was quiet too, except that more noise came in through the doors than the 80 Accord I had at the time. In fact I didn’t realize how quiet it was until I rode in a friend’s similar truck that had a rear window slider and a pass-through to the canopy. Even with the slider closed the roar was nearly deafening.

  • avatar
    Martin Schwoerer

    Jack,

    thank you for your interesting comments.

    In my neck of the woods punctured tires are not considered to be a major safety risk, but underinflated tires are. So new regulations say that all cars will require pressure monitors in the future,
    http://www.thetruthaboutcars.com/eu-regulators-go-for-gadgets/
    . On the other hand, I have read reports whereas tire dealerships tend to screw up the difficult process of replacing runflats — and these have lead to several accidents. All in all, I think the case for runflats is not at all clear.

    When you say that tires are the only noise factor, then I wonder why contemporary cars have a span of decibel ratings from 66 to 73 dba at 80mph, equivalent to a difference of about 200%.

    Also, if the contact patch area is the determining factor, then why aren’t cars equipped with skinnier tires quieter? All things being equal, you might say they are, but all things, as so often, are not equal.

  • avatar
    Nicodemus

    “Rolling resistance is a factor of friction”

    er no it’s not!

  • avatar
    cdotson

    I will chime in with agreement to several posters who comment that sound quality (the “art” of the noise) is independent of sound power level. When someone describes the impressive tone of a luxury car as a muted white noise they are describing the lack of prevailing frequency spikes.

    The only way to “measure” noise is with a time-averaged, background-corrected, full frequency data logging upon which an A-weighted compensation calculation is run. Hand-held devices attempt to duplicate this but I’m not sure how close they get. They are indeed worthless for engineers trying to diminish the standout noises as they cannot identify the frequency of those noises.

    Regarding the seating surfaces and their affect on noise; the leather would certainly reflect high frequency noises better than cloth. I doubt cloth/velour upholstery did much to diminish noise much below the very high-end of the audible frequency spectrum. Material used to eliminate reflected noise in anechoic chambers is typically made of very large-pore foam or low-density fibrous mats whereas the foams and cloth in vehicle seating is pretty dense and tight pushing its “absorption” range toward very high frequencies.

    I have to wonder how much of the perceived worsening of road/tire noise is due to the general increase in structural stiffness of vehicle’s chassis over the past 20-30 years. Structure-borne vibration propagates much better in rigid bodies and is much more difficult to attenuate.

  • avatar
    Lokkii

    Various ramblings….

    Honda/Acura is indeed the worst. They lost me as a customer because I couldn’t stand the horrible noise levels in my last (97)Integra. My 98 328i was excellent compared to the Acura, and was really very quiet except for tire noise.

    My 08 328i has the runflats, and they’re noisy and coarse sounding.

    BMW has apparently cared about interior noise and the characteristics of that noise for a long time – down to tuning the sound of the turnsignals, and – most interestingly (to me anyhow) putting a sound-tube in the Z4 to transmit tuned engine-noise into the cockpit deliberately. Apparently, you couldn’t hear the engine well enough with the top down, so they ‘amplified’ it by running a port through the firewall for no other purpose than carrying the sound.

    Finally – Noise cancelling. Like everybody else, I use noise cancelling headphones when I fly. I’ve often wondered why no one else has followed Acura’s lead in installing such systems in luxury cars.

  • avatar
    Gottleib

    Good and educational topic. I wonder what the noise ratings were when in 1965 Ford claimed their car to be quieter than a Rolls Royce at 60mph.

    For posterity I recall hearing in 1965 from some Rolls Royce owners that had the test been conducted using a Silver Cloud I with the straight six cylinder engine instead of a newer Silver Cloud III with the V-8 engine, the Ford would not have been quieter. I don’t know if this is just sour grapes but at the time I do recall that V type engines tended to have more vibrations than straight type engines.

    Also both the 1965 Ford and the Rolls used in that test had body on frame constructions. Do you think the more prevalent use of unit body construction has contributed to the amount of noise transmitted tot he passenger compartment?

  • avatar
    NickR

    It would be interesting to see what noises people like and don’t like, and what pitches. I imagine if I had the latest Mustang Bullitt, I’d drive with the windows down, heat full on, in the winter just so I could hear the exhaust rumble.

  • avatar
    netrun

    Awesome article! Excellent topic, well-written, and extremely informative!

    Couple of points:
    1) Sound waves have a length dependent on their pitch. The higher the pitch, the higher the frequency, the shorter the wave. Thus it is easy to eliminate high pitch squeaking noises with a bit of thin foam. Lower frequency noises are harder to block because you can’t fit the thicker foam in between the parts of the car (dash, doors, etc).

    2) Sound quality in vehicles is not only subjective, but also dependent on the quality of the listener. This matters because it’s the Executives at the car companies who get last call on whether a noise is worth eliminating ($$). This is supposed to be a profit industry, after all.

    3) You can make any car you own significantly quieter. @davey49: Yes, your Saturn is LOUD. They all were. Buy some of that asphalt based ice dam protector stuff for your roof, a 30′ roll should go for something like $30 at Home Depot. On a HOT day, install it under the carpeting, under the roof liner, and under the plastic interior door panels. You will get a huge benefit from doing this. You will have to push the stuff in place and sometimes use a hairdrier to get it to conform to the sheet metal shape. But it will make your car noticeably quieter!

    4) Wagons (2-box designs) will always be louder than sedans (3-box designs). This is because the noise from the rear wheels has a clean path to the passengers in the wagon. The seats in the sedan act just like foam always does – absorbing sound waves up to the thickness of the foam. That said, if you cover the floor of the wagon with the roofing stuff I mentioned, you’ll enjoy a quieter ride.

    5) This article has made me re-think selling my ’95 M-B E320 wagon. I dread the thought of listening to all the noises I’ll hear in any replacement car I get!

  • avatar
    ponchoman49

    I rode in a 2008 Buick Lucerne with the 3800 series III engine. It was earily tomb like in quietness. I was therefore quite shocked driving in my bosses 2004 Lexus ES and noticed lots of tire noise and wind rush on the exact same route.

  • avatar
    Lokkii

    netrun

    “You can make any car you own significantly quieter. @davey49: Yes, your Saturn is LOUD. They all were. Buy some of that asphalt based ice dam protector stuff for your roof, a 30′ roll should go for something like $30 at Home Depot. On a HOT day, install it under the carpeting”

    I hated the noise levels in my 97 Integra enough that I actually did this…. it helped quite a bit but wasn’t a wonder-cure…

    However, I did have trouble refitting the carpet after I’d made the floor thicker. Just something to keep in mind. I made it work, but there was some hassle involved.

    I never understood why Acura didn’t fix this… my thoughts were that it wouldn’t have cost more than $10 or so, and it wouldn’t have increased the weight of the car enough to notice….

    I quit asking why, though, and went to another brand of cars.

  • avatar
    Mark MacInnis

    Martin…in addition to the point you made about cost reductions, remember also the point of diminishing returns. Perhaps the additional costs (material cost, and effeciency cost due to weight penalty, for example) of making autos incrementally quieter is considered unacceptabled by the market…and scarce resources may be more rationally committed to other vehicle characteristics considered more desirable by the greater number of potential consumers.

    Just sayin’

    But the B&B seem a bit conflicted on this issue, anyway. I have have read a number of articles and posts on this site waxing lyrical about the sublime roar of the V-8 and V-12, and bemoaning the quirky silence of the Prius…..so which is the better automotive quality? Sounds of Silence or the Sweet roar of the open road?

  • avatar

    Mark:

    Yes.

  • avatar
    Martin B

    David Ogilvy of Ogilvy and Mather came up with the slogan At 60 miles an hour the loudest noise in this new Rolls-Royce comes from the electric clock.

    I recall looking in the engine compartment of an early-70s Rolls-Royce. The top of the engine and the plug wires were covered in rubber about half an inch thick. I don’t know if this was for silence, or to enable milord to drive through his private trout stream with nary a splutter from the engine.

    Oh, and apparently a Rolls-Royce engineer read Ogilvy’s advertisement and said, “We must do something about that damned clock.”

    • 0 avatar
      pauld101

      I believe this was a re-work of ‘The Autocar’ test in their edition for 27th April 1907:
      “At whatever speed this car is being driven on its direct third there is no engine so far as sensation goes, nor are one’s auditory nerves troubled driving or standing by a fuller sound than emanates from an eight-day clock.”

  • avatar

    As much as 90% of the car’s noise can come from the tires. go here:
    http://www.ehponline.org/docs/2004/112-11/forum.html

    and scroll down to EU Ramps Up Noise Mitigation (or something like that) by yours truly

  • avatar

    My ’99 Accord is not terrible but it’s not exactly quiet. I wear ear plugs on long drives. (After reading this, I may measure the db level on the highway. Of course, it’s probably higher right now because of the snow tires.)

  • avatar
    Nicodemus

    “David Ogilvy of Ogilvy and Mather came up with the slogan At 60 miles an hour the loudest noise in this new Rolls-Royce comes from the electric clock.”

    Actually he didn’t come up with the slogan, he quoted it from a journalist reviewing the Silver Cloud for ‘The Motor’ magazine.

  • avatar
    brandloyalty

    If you have a car that’s too noisy, but you like otherwise, you can add sound insulation. Either by yourself or have a car stereo place do it. A very simple and cheap fix is to buy rubber foam insulation tape and add a row of weatherstripping around the door jams, arranged so it seals. This is exactly what the manufacturers have been doing. Up to about 1990, cars had only one row, and some now seem to have three rows of weatherstripping.

    Without too much trouble you can line the doors and floor with stuff like b-quiet or dynamat. You can get automotive felt carpet backing to stuff into cavities. To go all the way, you can do the roof, trunk, pillars and the fender liners.

    I’ve added soundproofing to our last three cars, and for $150, about 15lb of added weight, and a few hours work, you get noticably less noise and also the impression of a more refined vehicle. The longer you plan to keep your car, the more sense it makes to do this. The sound system sounds better too, which is why this is part of installing a high-end system. I have no idea what it would cost to have someone else do this.

  • avatar
    Martin B

    @ Nicodemus

    Actually he didn’t come up with the slogan, he quoted it from a journalist reviewing the Silver Cloud for ‘The Motor’ magazine.

    Interesting. I didn’t know that.

  • avatar

    I wear earplugs to and from work because of the road/tire noise and the horrible auto trans gear whine. Chrysler dealer will not fix the whine in my “remanufactured” transmission that is pouring oil out the tailshaft and cannot find “D” for about 10 seconds after backing it out of the garage.

    They claim Chrysler has all but abandoned warranties and they’d just end up eating it.

    You just caused 100 chryslers not to be sold.

    Compare this attitude with Acura, replacing zillions of transmissions, out of warranty and politely !

  • avatar
    Voice of Sweden

    Martin Schwoerer and Brock_Landers> The magazine “Vi Bilägare” did this test at 90 km/h on noisy Swedish roads.

    The results from quiet Swedish roads were somewhat different. This indicates the major problem of comparing different measurements between cars.

    First the tires have to be the same design and size.

    Second, the road have to be the same – and since roads are worn (especially in sweden where we use studded / spiked tires in the winter) you hardly can compare two measurements on the same road if you let one year pass.

    Third you have to carefully calibrate the measurement equipment

    Fourth you have to measure at exactly the same position, perhaps at the drivers head. Different positions may have different noise.

    Fifth the wind conditions should be the same – outside winds can influence wind noise.

    So why is Swedish roads so noisy? Because we use a “special” form of asphalt called skeletal asphalt (at least in Swedish: skelettasfalt). This is a type of asphalt with very large “pores”, that make it noisy, but gives good friction, it’s not very dark (good in the winter) and it’s wear resistans (remember spiked tires!).

    What makes this problem worse is that as was said, manufacturers very carefully select the test drive location during car launches. So the comments from Swedish car journalists are “the car was quiet, but we have to test it in Sweden to know more.”

    And yes, my car is ranked as rather quiet – though I hate the noise inside it, and I long for a more quite ride.

  • avatar
    Scott

    I agree that a broadband dB(A) rating is not at all useful in subjectively evaluating the noise level and signature of a particular car. Such ratings can be useful from a very general objectively comparative sense (noise sources tend to be common among all cars, so noise signatures should be generally similar), but they give no sense of what a car actually sounds like. What would be helpful would be a narrowband noise curve (taken at a standard speed/temperature/road condition/whatever) that could be compared to other cars, as well as to whatever noise baseline you might choose.

    cdotson: I have on my desk at this moment a handheld device that does indeed measure time-averaged full-frequency noise with narrow band analysis possible, producing data that can be used (indeed, has been used by me) to track down, real time, specific frequency spikes in the background noise signature. It can even localize the noise source, if an additional mic is attached.

    And for the record, for interrupted sound sources, a sound pressure level (SPL) change of 3 dB is widely regarded as the minimum to notice a difference. That is, riding in an old Golf, then getting out, taking a break at a rest stop, and riding in a new one (a delta of 2 dB SPL) would not produce a noticeable change, unless the noise signatures were significantly different, but even then, the differences observed would likely be of frequency, and not level. 6 dB SPL is considered a significant difference, and 10 dB SPL can be correlated with a perceptual doubling of loudness.

    • 0 avatar
      hgrunt

      Very neat reply! I had wondered about measurement methodology, especially regarding measuring sound pressure.

      I agree with the un-usefulness of broadband dB(A) ratings. Some “quiet” cars don’t seem all that quiet. I remember riding in the back seat of an LS400 when it was fairly new, and finding it rather noisy because so much road noise filtered into the back seat. Then there’s the difference between having noise from something pleasant, like engine growl, vs. constant tire noise in the middle of hearing range.

  • avatar
    joeaverage

    I prefer small cars but I prefer cars more like an Audi TT than a VW Fox b/c of the efforts made to control noise and vibration. I don’t need too much sophistication but noise control is more important the older I get.

    Yes my ’99 CR-V is pretty noisy and is caused by several sources. Low gearing is the first problem. I’ve long wished for a 6th gear. Road noise is the second problem (and improved with better tires after the OEM versions wore out) and the third is wind noise (need to adjust the driver’s door tighter). The driveline gets noticeably quieter at 75 mph though. Dunno why. I have put off trying to sound proof the interior for 170K miles but ought to since we’ll keep it considerably longer. Not going to hurt the resale or anything.

    I’ll plan to do that once warmer weather is reliably here again.

    My VW suffers from a noisy exhaust. Catalytic converter vibrates b/c the joint ahead of it is worn out and loose. Parts in the mail.

    And then there are my aircooled VWs. If anyone has an especially noisy vehicle look for sagging motor mounts. My ’78 VW van had one mount that was torn allowing the bracket above the bellhousing to touch the frame and transmit 100% of the engine noise to the interior. I did not find that until I implanted the Corvair motor. Our friend’s ’78 VW van was MUCH quieter and even more so after she had a new interior put in with thick foam cushions and padded door panels (i.e. not vinyl with almost no padding). Really changed the character of the vehicle and is much nicer to travel in. I’ll be doing the same with our bus.

  • avatar
    Tinman

    This is the best discussion of car noise I’ve seen.Two years ago I was tired of noise and went looking for a quiet car but was not impressed.I test drove a variety of vehicles from mid size to cheaper luxury vehicles(Lexus 350) but couldn’t justify paying the difference in price for little difference in noise at higher highway speeds.One of the problems I was trying to address was the difficulty having a conversation with relatives with hearing problems.Obvious funny remarks aside(relatives and poor hearing),hearing problems are growing at a rapid rate due to the aging population among other things.Background noise is a big problem for people with hearing disorders and so ambient noise in a vehicle can be very troublesome.Ironically, many people with hearing problems are unaware of this so the demand for quieter vehicles may be grossly understated.And I was tired of getting in my car in the morning I being blown out of the cabin when the radio came on.
    The comments about an in cabin PA system are music to my ears.We have the technology and the costs of such technology has dropped dramatically over the years.But we don’t want to be amplifying (creating more noise) if we can solve the origin of the problem by reducing noise at its source.
    It was total frustration trying to get an informed conversation about car noise from a car sales person including suggestions about the best tires to use etc. I did bring my new car to an after purchase shop and had some sound insulation installed…not sure if it helped.
    After reading the other comments I feel at least more informed and more aware of some of the issues and thanks to everyone for that.

  • avatar
    harrikens

    Hyundai Santa FE 2012 base line, @ 130kmh or 80 mph = 73 dB measured with iPhone app.


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