Audi knows from sound, and it wants its upcoming plug-in cars to have as distinctive a grumble as possible, just like its fossil-fuel-burning brethren. That's why Audi engineers are working on "new sound signatures" for future e-tron models. You can tell how seriously Audi is taking this by the way it references the sounds a car makes to music and "emotional sound structures" in the press release below.

The stated reason for all this e-sound work is so pedestrians will be able to hear the near-silent EVs, but you could just use any old beep to meet that requirement. Audi wants something a bit more refined, to stand out from the space-y blips that the Nissan Leaf puts out or the Volkswagen E-Golf's baby Wookiee growl.

Scroll down to see a video of the Audi e-sound in progress. In its current form, the sound changes based on what the e-tron is doing. It comes out of a speaker blasting up to 40 watts that is attached to the bottom of the car.

Of course, the question from some blind-advocacy groups is whether having each EV make its own sound is reasonable, or if there should be one "EV sound" that all battery-powered cars are required to emit to tell those with limited sight "a car is nearby." In the U.S., the laws governing EV sounds are not yet set, but some sort of low-speed warning requirement seems to be coming.
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Acoustic innovation: e-sound by Audi

The brand is developing new sound signatures for its future e-tron models

A control unit generates sound based on signals from the car

A loudspeaker broadcasts the sound signature

Ingolstadt, April 5, 2012 – Audi's future e-tron models will cover long distances powered by practically silent electric motors. To ensure that pedestrians in urban settings will hear them, the brand has developed a synthetic solution: Audi e-sound.

Rudolf Halbmeir's workstation is not exactly typical of an Audi engineer. There is a digital piano on his desk, two studio-quality loudspeakers next to his computer monitor, and a pile of music magazines off to the side. "A car's sound," says Halbmeir, an acoustics engineer, "is similar to music."

Sound is an especially exciting aspect of a vehicle. Although it can be described in physical terms, there is no substitute for experiencing it firsthand. A car's sound is emotional, not intellectual. Although we consciously register a car's sounds only occasionally while on the road, they are always there – playing a crucial role in the driving experience. Sounds send signals. Low-range frequencies suggest power and composure, while mid-range frequencies emit sportiness and agility.

All Audi models produce sound signatures which are not only well-rounded and harmonious, but also broadcast performance, premium quality and respectability. "Good sound design is a complex endeavor," explains Dr. Ralf Kunkel, Head of Acoustics at Audi. "We have gathered a lot of expertise over the years. We have also learned how to amplify pleasant frequencies and to suppress unpleasant noises."

In a series-production Audi, a combustion engine currently supplies the music. Conversely, the motor in an electric-powered e-tron is not an option, as it is too quiet and its high frequencies are not exactly melodious. Audi's e-tron models will therefore feature a synthetic sound signature. Rudolf Halbmeir teamed up with his colleagues Axel Brombach and Dr. Lars Hinrichsen to create it.

They used computers to do most of the work. Using software to mix and listen to tones, assess, and then re-mix: Halbmeir is truly enthusiastic about the creative process. After all, in his spare time, he writes songs and composes music in his own recording studio – where he himself plays a lot of instruments. "I create one-of-a-kind emotional sound structures," says Halbmeir. "There aren't many differences between music and a vehicle's sound. I trust my instincts and have to try out new ideas to determine where they will take me."

Which ideas, exactly? "Some science-fiction films provided inspiration suitable for certain frequency ranges," responds Halbmeir. "But there was nothing in the real world which offered quite the right sound. When you compose music or sounds, you have to be true to your convictions. The moment you cut corners, you essentially end up with elevator music." Dr. Ralf Kunkel adds: "Because we here at Audi are all automotive experts, we have a great advantage over sound specialists elsewhere. We know our vehicles inside and out, not to mention how they operate and behave."

The e-sound by Audi may be artificial, but it is authentic. In fact, the e-tron itself generates its sound by the millisecond. Dr. Lars Hinrichsen, the expert for hardware and software, explains: "Data relating to the electric motor's rotational speed, vehicle speed, loads, and other parameters is continuously supplied by the vehicle to the control unit. It then uses this data to generate sound."

The e-sound is played via a sturdy loudspeaker attached to the car's undercarriage. Axel Brombach, the specialist in this field, shares details: "We designed it to handle as much as 40 watts, but during normal operation it ranges between five and eight watts. That's loud enough for nearby pedestrians and cyclists to hear the e-tron." A fraction of the sound signature enters the vehicle's interior via airborne and structure-borne sound waves."We could utilize sound paths and mechanical actuators for more sound in the interior," explains Dr. Kunkel. "After all, a vehicle body is basically a large soundboard.But we believe strongly that our e-tron models call for an atmosphere of calm, which best conveys the unique experience of electric driving."

Key measurements: the acoustic test bed

A change in scenery: the acoustic test bed on the building's ground floor is a large room, spanning some 350 qm with a seven-meter ceiling. Dense rows of wedges full of glass wool, each a meter in length, project from the walls. These wedges absorb a majority of any sound energy; things sound almost like they do outdoors. In the middle of the room is a dynamometer test bed, between two long rows of microphones atop tripods. The dynamometer serves primarily to measure noise as if the vehicle were driving by, with tires on the roller and the microphones gathering acoustic data.

Halbmeir and his colleagues used the acoustic test bed to achieve many key advancements for the R8 e-tron prototype, which features e-sound technology. All the while, they had to remain aware of regulatory developments. Dating back to early 2011, guidelines are being crafted in the United States regarding the volume of alerts emitted by electric vehicles."We'll probably have to ensure audible alerts only up to 30 km/h; above that speed, the tires generate enough noise," says Dr. Kunkel. "But that isn't quite satisfactory – we'll surely increase the upper limit for alerts."

"The test bed was a key development tool for us," says Axel Brombach. "It did not, however, allow us to genuinely evaluate the e-sound. We were missing everyday conditions such as motion, wind, and other vehicles. So we then drove on actual roads. Listening, seeing, feeling: they all go together."

Out of the building and to the street. A red Audi R8 e-tron pulls up around the corner, purring gently. But when Rudolf Halbmeir taps the gas pedal, the purr turns into a cultivated growl. Though not unlike an elegant V8, it is especially pure and nuanced, and is shrouded in bright and innovative overtones. The Audi R8 e-tron certainly sounds like a sports car, but also one-of-a-kind and very futuristic. Halbmeir stops the car and inquires with a grin: "Great, isn't it?"

And e-sound for this electric-powered high-performance sports car is just the beginning. Each and every Audi e-tron model will have a sound signature all its own – similar, yes, but each one unique. Because an Audi's sound is not just any music: it is Vorsprung durch Technik to one's ears.


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    • 1 Second Ago
  • 26 Comments
      • 6 Months Ago
      That is just dumb and immature. If people haven't learned how to look both ways before they cross the street or road, then maybe they should get hit to teach them a lesson, and if you are thinking about those 400 million blind people wondering aimlessly by themselves on the streets or out in the middle of the roads, then the same fate should apply to them.
      MTN RANGER
      • 6 Months Ago
      I'm getting my wire cutter ready for when this is mandatory.
        Letstakeawalk
        • 6 Months Ago
        @MTN RANGER
        Bad idea indeed. By circumventing Federal or State mandated equipment, you're opening yourself up to some pretty serious legal liabilities. Hacking it to change the sound might be an OK alternative, as longs as you still comply with the sound volume requirements (whatever they may be).
        Anderlan
        • 6 Months Ago
        @MTN RANGER
        Better, hack it to make your own customized sound. I'd like a Harley-Davidson chopper noise on my Twizy for maximum hipster irony. This could be bad. Car ringtones.
          Spec
          • 6 Months Ago
          @Anderlan
          I love the idea of CarTones. Use the Jetsons sound. Use an old VW bug sound. Use train sound. Use a motorcycle sound, but you might not be able to use the Harley-Davidson sound since I believe they tried to trademark it.
          DarylMc
          • 6 Months Ago
          @Anderlan
          Hello Anderlan That's exactly why I wouldn't rule out supporting a government mandated or universal sound:)
      marcopolo
      • 6 Months Ago
      @Dave mart Normally, I am a strong supporter of road safety measures. However, even I recognise that installing an unproven device based on a knee jerk reaction to an imagined situation, can be counter-productive.. I have no objection to a proper study being undertaken, and the results submitted for consideration. But just to act upon the emotional guesswork of vested interests is neither a responsible, nor efficient use of regulatory powers.
      Alfonso T. Alvarez
      • 6 Months Ago
      I remember when it was first discussed that EV's should have a distinct sound that blind people could easily discern and be made aware of one approaching - many of the less than intelligent posters on here had serious hissy fits, typically something like "...wah, wah, wah, that is one of the great things about EV's - they eliminate the sound pollution that is caused by the evil ICE engines!!" Never mind that blind people NEED to hear vehicles coming to determine when cross traffic stops, when it is safe to walk across the street, etc. 'US GREEN WIENIES DON'T CARE ABOUT THEM BLIND PEOPLE - they should just stop trying to lead normal lives if they need to continue this ICE noise pollution! It made me want to puke then, it makes we want to puke now! I am handicapped in a different way, so can understand why this is a huge issue and frankly cannot comprehend why those who claim to be 'environmentally concerned' cannot see the error of their viewpoint!! SHAME ON YOU!!!!!
        Tysto
        • 6 Months Ago
        @Alfonso T. Alvarez
        I'm with EJ. It's always a driver's responsibility not to hit people, blind or not. And some ICEs are so quiet at low speeds that you can't hear them over background noise from a nearby road. Why should EVs be burdened with a lantern and red flag? This is all just a reaction to novelty. http://en.wikipedia.org/wiki/Red_flag_laws
        DaveMart
        • 6 Months Ago
        @Alfonso T. Alvarez
        EJ: At what level of background noise is it possible to hear a car from the tyre noise alone? How acute are you assuming the hearing of the person is as people who have vision problems are not immune to having poor hearing? Do you imagine that being hit by a '180lb road biker' is as likely to result in fatality as being hit by a 3,000 lb car travelling at 30 mph? You are talking pure nonsense. I suggest if you have any ambition to find out what you are talking about you go along to a course, as I have done, where you will be blindfolded and able to, under much more controlled conditions than vision impaired people have to get around in, try your hand at crossing roads without vision. I don't think you will be quite so heroic on behalf of others after trying it yourself.
          Neil Blanchard
          • 6 Months Ago
          @DaveMart
          When I walk to pick up my kids from school, the driveway is curved, and ALL the vehicles are quiet enough to make the first sound you hear be THE TIRES ON THE PAVEMENT. The exceptions are only those cars with broken exhaust systems. So, I think that the noisemaker-on-electric-cars thing is a solution in search of a problem. Having said that, my sister-in-law drives a Leaf, and the sound it makes is almost subliminal -- if you don't know that it is making it "on purpose" then you would not consciously notice it. So, much ado about almost nothing. Neil
          Letstakeawalk
          • 6 Months Ago
          @DaveMart
          As a commuting bicyclist, I can tell you that most of us are going nowhere near 30mph. Indeed, unless you're training for the Olympics, even a sustained 20mph is pretty fast! I'm generally going around 12mph when I'm in a hurry, and even at that speed I *do* have to be very aware that pedestrians may step off the curb unaware that I'm passing by. It is for that reason that I have a bell - required by law, just as these noisemakers are required for BEVs. Do I complain about having to have a bell? No, because I understand that it is more important that I do everything possible to make my presence known in order to avoid collisions with others. Fortunately, my brakes are very adequate, and my bike is very maneuverable. Still, I can count two occasions where I have hit a pedestrian (one stepped off the curb in the rain without looking to see if the way was clear, the other was a jogger with headphones on), but in both cases we simply got back up, brushed ourselves off, and continued on our ways. Anyone who equates getting hit by a bicycle going less than 10mph, and a car moving the same speed, doesn't understand the role mass plays in the equation. The one time I was hit by a car (their fault) even though it was only going 5mph it crushed my bike and sent me to the ER.
          EJ
          • 6 Months Ago
          @DaveMart
          "Do you imagine that being hit by a '180lb road biker' is as likely to result in fatality as being hit by a 3,000 lb car travelling at 30 mph?" My Leaf's artificial noise cut's off @18mph. Why? Because by then tire noise is enough for people with normal hearing to hear it. So you're not going to be hit by an EV at 30 because you didn't hear it. However a road bike @30mph is silent until it's too late. And it's braking and maneuverability are vasty inferior to any car. Plenty of people have been killed and permanently disabled by bicycles. But if you want to try for yourself, have at it. F=ma. 'I don't think you will be quite so heroic on behalf of others after trying it yourself.' And if I was blind, it wouldn't change me thinking that the world shouldn't have to be subjected to making noise to accommodate me in my .3% sliver of the population.
          marcopolo
          • 6 Months Ago
          @DaveMart
          @Dave Mart EJ is correct, the facts are against you. I realise you can create an emotional scenario for almost any situation, but society must be realistic. Apart from the study on guide dogs, no realistic study has ever been completed. Society, cannot not be designed to cater for every contingency. It's most unfortunate for those who are crippled, blind, deaf, mentally, and physically impaired. However, there is a limit to which society can accommodate such disabilities. It sound harsh, but so is reality, pretending otherwise is hypocrisy ! there are also those who suffer from allergies, (some life threatening) shall we ban the sale of peanuts, ban pollen etc etc , ? At some level, commonsense must prevail ! The efficacy of such a device must be proven by realistic and impartial trials before we rush to create what may well prove ineffective, except to create a new problem.
        EJ
        • 6 Months Ago
        @Alfonso T. Alvarez
        Shame on me then. The simple fact is that road noise is more than enough to hear a car coming ,and that a 180lb road biker is far more dangerous to a pedestrian as they a almost completely silent at speed until its too late.
      IBx27
      • 6 Months Ago
      Sounds terrible.
      marcopolo
      • 6 Months Ago
      Alfonso T. Alvarez , is right ! Well ok, I know that blind people develop acute hearing that can easily detect the sound of automobile tyres etc. Yeah, yeah, I know that outside the US, most Blind Institutes, have raised no objections, and the Prius, and other hybrids haven't proved a problem. In fact, more injuries to sight impaired pedestrians have been created by cyclists, who confuse pedestrians, and guide dogs, with unexpected behaviour. Guide dog trials, show the dogs make no distinction between ICE and EV, they respond to both equally. However, what about blind/deaf people ? Alfonso T. Alvarez's demand for a man with a red flag to walk before every motor vehicle, is not unreasonable ! Cyclists should be required to stop, and dismount, at the first sight of any pedestrian! Hmmm,... still, this wouldn't protect the children! (must protect the kiddies)! Oh, and what about traumatised, birds, and other animals, some may even be endangered etc etc ........ Sound regulations are an idiotic, waste of taxpayer funds, created by pressure groups of public busybodies. Far from being useful, such devices will become just another irritating noise pollutant. "A Solution in search of a problem" ! ( Charles H. Townes 1915-)
        Alfonso T. Alvarez
        • 6 Months Ago
        @marcopolo
        You see, I was right!! People don't have the right to put others at risk for their own selfish wants and many here reacted like I knew they would. Pretty pathetic from my perspective. And I have experience of what having a simple, non-intrusive sound generator would do. I was at a garage in the GM Milford Proving Grounds helping an engineer add some data recording equipment I had supplied to them to a Volt, when I went to move backwards away from the car - just as I moved back, a two mode hybrid full size truck was passing in electric mode - I luckily caught sight of it out of the corner of my eye and avoided getting hit - I heard NOTHING AT ALL from that truck. Here is the deal people - we have a lot of people in this country who have various handicaps that require some concessions to live as close to normal as they can. Luckily, your viewpoints don't reflect reality, as we have laws that help the handicapped be able to function in society, get a job and not have to depend on welfare. Apparently in your almighty and sadly caustic opinions, this is just wrong as they do not constitute the majority and should have to adapt to what the majority can do. So no ramped curbs, no automatic doors, ramps to doorways, etc., etc., etc. I would be hosed, but hey, just because I need to make a living - and support many employees at my firm (and many more at suppliers to us), why should I be able to gain access to engineers, managers and finance people to help my customers be more efficient at their jobs when it offends the sensibilities of people like you???
        Letstakeawalk
        • 6 Months Ago
        @marcopolo
        "Oh, and what about traumatised, birds, and other animals, some may even be endangered etc etc ..." I almost ran over a squirrel with my bike the other day... and it wasn't the first time! Once a squirrel's tail got caught up in the spokes, and it flung the little bugger a good ten feet into the air! Funniest thing I ever saw. Once it landed and regained its senses, it ran off, the cheeky b@$tard.
        DaveMart
        • 6 Months Ago
        @marcopolo
        To argue that it is inappropriate to to make alterations for the benefit of comparatively few people is to ignore that what is proposed is a trivial inconvenience to the many, but life or death for the few. It would be interesting to see if those who are not willing to put up with the smallest inconvenience on the grounds that it is cool to have a noiseless vehicle would change their perspective if misfortune struck them and they were part of the group affected. Familiarity has blunted the impact of road deaths and injuries, which are greater than fighting a major war. We should not waste our time on those who wish to continue their anti-social and destructive behaviour without hindrance. Dutch pedestrian priority areas, the Woonerf, are the way to go. There are no road markings and the driver of the cars are held liable for damage to lighter, less protected transport, and in their is an order of responsibility with motorbikes next, bikes next, and pedestrians the most protected. Electric cars are ideally suited to such a scheme, accidents are down massively and you get there nearly as fast anyway. The only reason that car drivers can have the present cavalier attitude is because insurance insulates them from it's effects. If they killed a pedestrian and had to pay the true cost they would be paying for the rest of their life, and would never consider going in pedestrian areas at speeds which might kill.. There are an awful lot of heroes on this blog, who rather than put up with trivial inconvenience indulge themselves in an I'm alright Jack attitude. One hopes that they never have to bear the consequences of such childish, selfish folly.
      Chris
      • 6 Months Ago
      I am totally for making EVs safer for pedestrians but I am against making EVs noisy, I drive one. One of the biggest benefits of EVs is how quiet they are and how relaxing the drive can be that way...not to mention those that live along roads will also benefit. Manufacturers need to work together on a solution like they are doing on battery tech - adding sound to a quiet car as a warning system to pedestrians is not the long term answer. myactivee.blogspot.com
      CanaDoc
      • 6 Months Ago
      I understand the need for some uniformity of sounds, but a Chevy Aveo doesn't sound like a Subaru WRX, so I think pushing for "one sound" might be a bit extreme. I know that ICE engineers consider a car's sound as something of a signature, why can't EV's be the same - within reason, of course.
      Alex C
      • 6 Months Ago
      Isn't this what the car horn is for?
      Chris M
      • 6 Months Ago
      "Audi" is Latin for "Sound" - the founder of the company wanted to use his own name, but found someone else had trademarked it. Since his name meant "hear" in German, his son, studying Latin, came up with the name they used.. For that reason alone, they really have to come up with a neat sound, and it sounds like they did...
      • 6 Months Ago
      I created a sound for the mini-e car. See sounds number 4 on the website www.elektrischrijdenhoeklinktdat.nl
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