HARMAN Automotive and Lotus Engineering have developed pioneering acoustic technology for the cars of the future. HALOsonic™, technology unites HARMAN’s superiority in developing and integrating premium audio systems in cars with the “Active Noise Control” technology of Lotus Engineering to make driving safer and more environmentally-friendly and to enhance the driving experience.  HALOsonic™ technology has the ability to generate authentic external engine sounds, particularly relevant for electric/hybrid vehicles, and internal engine sounds for all vehicles.  Road noise and Engine noise can be cancelled in order to provide a more refined driving experience. This innovative technology is production ready, today.

Electronically generated engine noises for electric and hybrid cars

HALOsonic™ External Electronic Sound Synthesis (eESS) generates synthetic engine sounds which serve to warn pedestrians and cyclists that the Hybrid or Electrical Vehicle (HEV)  is approaching when running in almost silent EV mode. Studies carried out by the University of California have shown that the human ear only perceives hybrid and electric vehicles within a radius of three meters. This creates potentially hazardous situations when parking and driving off, as well as emerging from side streets and off-street parking. People fail to realize that the cars are in motion because there is no engine noise. In addition, rolling noise is barely audible when vehicles are traveling at low speeds. Older people, those with visual impairment, children and cyclists are the groups at particular risk.

Statistics from The National Highway Traffic Safety Administration in the USA report that “For one group of scenarios, those in which a vehicle is slowing or stopping, backing up, or entering or leaving a parking space, a statistically significant effect was found due to engine type. The HEV was two times more likely to be involved in a pedestrian crash in these situations than was an Internal Combustion Engine (ICE) vehicle.” (NHTSA report DOT HS 811 204, September 2009)

Legislation is passing through government in the USA, Japan and Europe to stipulate a minimum noise level so that the increase of environmentally friendly, almost silent HEV’s does not become a new source of danger to other road users.  It is likely that legislation will require the external sound to be ‘engine like’.

The synthesized engine noise is transmitted externally by means of high-efficiency speakers located in the front bumper and, as an option, in the rear bumper. The speakers are particularly robust in design and will withstand climatic extremes and water ingress.
The sound transducers focus the sound generated by HALOsonic™ External Electronic Sound Synthesis in the direction of travel. This means that noise levels remain pleasantly low for other road users and bystanders who are not located within the direction of travel. Noise pollution in the cities is decreased considerably in comparison with vehicles with combustion engines.

The rear-facing sound transducer warns passers-by behind the HEV, who are potentially at risk that the car is performing reversing maneuvers. eESS is activated as soon as the driver starts the ignition. This is how the car signals to other road users that, potentially, it is about to move off. For authenticity, the engine sound generated varies with the vehicle speed and rev count. This means that pedestrians, cyclists and children can intuitively estimate the speed and direction from which the car is approaching.

Electronic sound synthesis is also used inside the car. HALOsonic™ Internal Electronic Sound Synthesis (iESS) generates engine noises to give the driver the familiar feedback relative to his speed: When he starts the motor or when waiting at traffic lights, the driver will hear the engine noise signaling that the car is in operation, while during a journey, the sound will create the impression of both speed and acceleration of the vehicle. iESS offers drivers and passengers of HEV’s greater involvement and a more pleasant driving experience. The iESS signal can be generated by means of a ‘stand alone’ HALOsonic™ ESS module with speaker inside the vehicle, or through integration with the onboard audio system. Thus, HARMAN offers perfect integration without adding to weight or requiring more space.

HALOsonic™ Internal and External Electronic Sound Synthesis (eESS and iESS) enables car manufacturers to give their vehicles their own acoustic identity through the choice of a specific engine noise. The choice of customer-specific sounds ranges from the classic combustion engine to attractive, futuristic sounds and anything inbetween

Electronic minimization of extraneous street and motor noises in the interior of the car

HALOsonic™ Road Noise Cancelation and Engine Order Cancelation systems can improve the sound conditions in the interior of a vehicle considerably, as well as offering additional design options for reducing the weight of the vehicle and optimizing fuel consumption. Diesel and gasoline engines, as well as the exhaust systems, suspension and tyres, all create noise and vibrations in the body of the car that were previously only possible to reduce with large quantities of insulating material. The Road Noise Cancelation and Engine Order Cancelation technologies reduce extraneous street and motor noises in the interior of the car. Electronic analysis systems determine the signal needed to provide cancellation which is then seamlessly generated through the in-car sound system. This means that weight can be saved because less insulation is required, making a significant contribution to reducing CO2 emissions and allowing automobile manufacturers greater design freedom.

HALOsonic™ offers electric and hybrid cars their own acoustic identity, makes a significant contribution to safety and energy efficiency, and ensures pleasant, stress-free driving.

For further information please go to HALOsonic.