Make some noise! The electric cars are coming
Electric vehicles will continue to make noise as being the future of mobility, but one big issue with it is that it hardly makes any noise. EVs only create an acoustic presence once tyre noise kicks in, and that means that it is nearly totally silent at low speeds thus making it potentially dangerous for other road users – namely pedestrians and cyclists, both which can include people hard of hearing and children – who cannot hear the vehicles coming.
Severe incidents resulting from EV/hybrids which are too quiet are not quiet common, but that doesn’t mean there has been no fatalities. An often cited example is a case in Japan where a guide dog and its owner was killed by a reversing EV whose driver had turned the sound emitter off.
The Royal National Institute of Blind People (RNIB) in the UK quotes a study which says that the lack of noise by quiet hybrid and electric cars at areas where pedestrians are likely to be are at a maximum of 30-50 decibels, a huge difference to current noise levels of 70 decibels at an average city street. In short, pedestrians are just not expecting the surrounding dangers. The ‘Silent But Deadly’ report also found that hybrid vehicles had to be 65 per cent closer to a pedestrian before they could be audibly detected.
This is why the European Union are making it compulsory by July 2019 for EVs and hybrids to emit noise when travelling slowly (under 20kph). The terminology used by the UNECE World Forum for Harmonisation of Vehicle Regulation WP.29 is AVAS or Acoustic Vehicle Alerting System. There’s no going against it too as existing EVs – those that emit no sound – must be retrofitted with a device that helps to make noise by 2021. The US is also making it legislation, effective 2020.
There is a guide for carmakers to follow in ‘designing’ the noise EV and hybrids will make – for example it cannot be paused or turned off, as it was in the case in Japan stated above. It will also be ‘directional’ to make the listener be aware of the vehicle’s location easier, even compared to a car using a conventional ICE engine.
The task in making this noise has turned into a science in itself. Automakers are now working with scientists, musicians, and acoustic experts to make the best sound. One question is obviously whether to replicate noise from a combustion engine or create a new artificial sound.
UNECE has put forward an idea of what AVAS may sound like, although you’ll have to agree that it – as you can listen in the audio clip below – was not made by someone who appreciates the emotional portion of driving.
Needless to say, most automakers already have a strong grasp of their direction, even if the outcome still does not feel right. Jaguar has the I-Pace’s Dynamic Audio and that’s likely a sensible point of reference; after all, while the company has only recently went down the electric path for a mass-produced model, the firm has been racing in Formula-E since 2016. The I-Pace’s sound surely is spicy, then?
Hang on, that’s not a load of difference from UNECE’s AVAS (read: dreary). Unfortunately, the origin for this has more sense (and science) than we’d like to admit, hence difficult to argue with. First, the agreed standard is a mesh of white noise and tonal sounds. The thing about the former is that it is pleasant-sounding. Examples of white noises are rainfall, crashing waves and even TV static. Scientifically, it is a random noise with flat spectral density throughout the audible frequency range of 20-20,000 hertz.
The second reason is that origin/direction of the white noise is easier to pin-point even without deliberately finding it, thus a pedestrian or cyclist may be able to react to it more effectively. This quality is crucial in increasing the effectiveness of any artificial noise meant for safety purposes. Conversely, noise made by regular petrol/diesel engines tend to bounce off hard surfaces and making it difficult to quickly figure out its origin. Think of it this way, you are more aware of a reversing heavy commercial vehicle (both of where the source is, and the fact that a lorry is reversing) because of the high-pitched beep it gives out, rather than the engine and exhaust noises.
The AVAS example and that from Jaguar is further underlined by Nissan’s sampling. It’s called Canto (it’s Latin for ‘I sing’, actually) and revealed during the last Tokyo Motor Show. Nissan worked with an award-winning composer and founder of Man Made Music, Joel Beckerman, to develop this.
“The Canto sound is made up of a unique combination of organic and electronic sounds. It took quite a bit of creative prototyping, experimentation, collaboration and refinements to get it right. We also had to determine how the sound would smoothly change pitch when accelerating or decelerating in a way that sounded completely intuitive and natural,” says Beckerman.
Is there hope for something more interesting? Well, Mercedes-AMG is reportedly working together with rock band Linkin Park to produce engine noise for the carmaker’s quieter cars. However, there has been no updates on that project so far.
Perhaps we can look to BMW, then. The new M5 is mega fast and drives so much better than the old one, and we can also confirm that it sounds furious. The reason for this is something not quite hyped up by BMW since it was introduced a few years back. It’s called Active Sound Design – a feature which basically amps up the sound coming from the engine using the car’s speakers. Yes, it’s piped in. Some say it is faked, others describe it as enhancing. In any case, the M5’s noise is for cabin occupants. EVs and hybrids need noise to serve the safety of those outside the car.
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