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Artificial car noises and intellectual property protection

24th Mar 2017

With Formula 1 (F1) starting this weekend, the topic of discussion and debate among many F1 fans will be the noise of the cars. There is a view that the newer generation of F1 racing cars, with their hybrid turbo-engines, are not as loud as the ‘screaming’ V8 or V10 engines of the past. Some fans say that ultimately the F1 experience is arguably not as enjoyable as it once was.

It has been reported that F1 teams have reacted to complaints from their fans by introducing modified exhaust systems to try to boost the audible engine sounds during the race. A few years ago, an example of an F1 team’s attempt at improving engine sound was Mercedes-Benz’s experimental ‘megaphone’ exhaust. Furthermore, last year the Fédération Internationale de l’Automobile (FIA) allowed the F1 technical regulations to change so that cars could have up to three separate exhaust tailpipes for the wastegate. In previous years the exhaust gases were routed into the main exhaust, effectively muffling the noise when the wastegate opened. F1 technology is often purposely not patented or design protected in an effort to maintain a level of fairness between the participating teams. For example, if one team had a monopoly on a piece of technology, it might also have a technical advantage that the other teams would not be able to access, effectively ruining any competition. However, the technology involved in car sound amplification or enhancement is being applied to conventional cars and consequently the IP landscape is changing in the automobile market.

The automobile industry has been incorporating sound effect systems into their hybrid and electric cars in order to produce artificial vehicle noise for some time now (e.g. one of Honda’s older patents). The reason for this was originally to ensure pedestrian safety. For instance, when driving a hybrid/electric car there is a trend for drivers to end up speeding without realising it because the sound produced by these vehicle’s engines often does not match up to expected ‘roar’ of a conventional internal combustion engine. Understandably, pedestrians who have also become accustomed to these traditional engine sounds might not recognise a speeding electric vehicle in their immediate vicinity. In 2008, a study at the University of California, Riverside found that blindfolded test subjects could hear a combustion engine from 28 feet (~8.5 metres) away, but could only hear a hybrid from 7 feet (~2.1 metres) away. The unintentional stealthiness of these vehicles can catch pedestrians and cyclists by surprise and contribute to traffic collisions. In the interest of road safety, legal requirements for car manufacturers to incorporate artificial engine sounds in their electrical/hybrid vehicles is increasingly being driven by government legislation. (See footnote).

The use of artificial sound to compensate for the lack of noise in electric cars is known, however manufacturers have now been adding sound to conventional cars. For example, in 2012 Audi introduced ‘e-sound’ to their e-Tron series of high-end electric vehicles which is primarily designed to replicate the ‘expected’ engine noise from a conventional combustion engine. However, the reasons for doing so are also aimed at improving the ‘audio-appeal’ of their electric/hybrid vehicles. More specifically, this ‘e-sound’ is played through a loudspeaker in the vehicle’s undercarriage in order to be audible to both the driver and pedestrians in the driving vicinity. In an effort to also appeal to customers of sports cars, Audi has developed hardware and software to replicate a specific sound that could be used to identify the car as an electric vehicle while still replicating the revving up and down sound-pitch changes caused by the acceleration/deceleration of conventional internal combustion engines.

Interestingly, BMW have recently taken the use of artificially generated engine sounds a step further by introducing this feature into their high-end BMW M5 model, a car which is neither an electric nor a hybrid vehicle. This is because, as vehicle noise regulations, technological advances, and general increases in build quality have continued to make vehicles ever quieter (both outside and inside), the BMW M5 chassis is now so well sound isolated that passengers and drivers struggle to hear the sounds produced by its own combustion engine. BMW’s solution is the M5’s ‘Active Sound Design technology’, which artificially replicates engine noise in the car’s cabin using its stereo system. It comprises a digital signal processor connected to its engine management system computer and plays an artificial simulation of the car’s twin-scroll twin-turbocharged V-8 engine noise through the stereo system in sync with the car’s actual 560-horsepower. The system not only matches the engine’s activity, but adjusts its output for the car’s various software-controlled sport driving modes. The precise sound sample is determined by engine load and rpm, where the audible sound is also processed in an effort to edit out any undesirable sounds. Some of the real engine sounds are still audible to the driver, so the recording is more of a backing track. The unique features of the technology behind artificial vehicle sounds and the hardware systems that create and play these sounds are clearly patent-protectable. Looking at some recent US patent applications, this area of technology is now often termed ‘vehicle engine sound enhancement’ systems. Looking at Bose Corporation’s US patent applications, it is clear that it is not only the automobile manufacturers that are interested in patenting this type of technology but also consumer electronics manufacturers that are able to produce the technology for these cars (e.g. integrated sound systems).

Traditionally, consumer products have had their acoustics deliberately tweaked for market appeal. For example, car manufacturers soon grasped that when someone views a car in a showroom, it is probably not the engine they first listen to but rather the sound of the car’s doors opening and closing. In other words, sound is a really vital first impression and therefore a lot of thought goes into how cars sound. For example, when car manufacturers began adding extra cross-bars in their side doors to comply with crash safety standards, they were forced to make other parts of the car lighter by removing material from the catches and door mechanisms in order to compensate for the added weight. As a result, these doors no longer produced the satisfying ‘clunk’ and instead made a tinny sound. Consequently, car manufacturers continually introduce and patent innovative dampening systems for the door cavities in order to muffle such tinny sounds (e.g. a US patent application for an acoustic vibration damping system for a car door). Furthermore, design engineers also modify the door locking mechanisms to make the desired ‘high quality’ closing sound (e.g. Ford’s US patent for an energy absorbing latch). The engineering of artificial consumer product sounds is certainly not unique to the car industry. For instance, the satisfying shutter noise produced by digital cameras is just one example of a sound that is artificially fabricated to make a modern gadget imitate older technology in an effort to appeal to consumers.

A sound is not an invention and is therefore not patentable, however many of the artificial vehicle sounds might be protectable by other forms of intellectual property. Like music, artificial vehicle sound recordings can be sufficiently creative to qualify for copyright protection. The computer software used to create and play these sounds can also be protected by copyright law. In practice, it seems difficult for vehicle sounds to be registerable as trade marks. For example in 2000, after six years of litigation, Harley-Davidson dropped their efforts to register the sound of their V-twin motorcycle engine in the US after lengthy legal oppositions from their competitors. However, in principle, distinctive sounds can acquire ‘secondary meaning’ which might make the sound eligible for trade mark protection once consumers associate a sound with a particular manufacturer.


This article is for general information only. Its content is not a statement of the law on any subject and does not constitute advice. Please contact Reddie & Grose LLP for advice before taking any action in reliance on it.


Japan’s government issued guidelines for such warning devices back in January 2010 and the US approved legislation in December 2010. In November 2016, the US National Highway Traffic Safety Administration ruled that warning sounds are mandatory from September 2019 for electrified vehicles travelling at less than 19 mph (30 km/h) or going in reverse. The European Parliament has also approved legislation that requires the mandatory use of ‘Acoustic Vehicle Alerting Systems’ for all new electric and hybrid electric vehicles within 5 years after publication of the final approval of the April 2014 proposal to comply with the regulation.

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