For many years, car makers have competed against each other to create the most comfortable and luxurious driving environments, including reducing the impact of irritants such as road noise. The introduction of hybrid and electric vehicles has pushed manufacturers to go even further in the development of quieter vehicles. However,whilst being more environmentally friendly than combustion engines, this new generation of vehicles could pose a higher risk to pedestrians due to their near silent running resonance.
To help prevent serious injury and deaths due to collisions with quieter vehicles, the EU has decided that by 2019 all hybrid and EVs must generate a noise when travelling below 18.6pmh to improve pedestrian safety.
Noise issues aren’t just restricted to outside the vehicle. Another trend in automotive manufacturing has been the use of lighter materials and increased efficiency of vehicles which, whilst beneficial for the environment, has resulted in increased noise in the cabin.
Now one company claims it has created a solution to these problems in its latest HALOsonic system; a suite of active sound management systems which is able to balance both noise and sound, raising both drive comfort and safety. HARMAN, recently acquired by Samsung, is better known for its premium audio systems from the likes of Harman Kardon, Mark Levinson and JBL but expertise derived from recreating authentic sounds is now helping in and out of the car.
HALOsonic comprises a range of technologies that aim to manage noise and deliver sound:
1. Road Noise Cancellation (RNC)
Road noise generated by tyres and the road surface can permeate into the cabin and be droning, creating driver fatigue. The HALOsonic system monitors signals received from accelerometers placed in suspension and chassis, predicting what noise will be transferred into the cabin. The RNC generates an anti-noise wave which enables the car cabin to be quieter and more comfortable.
2. Engine Order Cancellation (EOC)
Noise generated by the engine can be substantial, however, using sound deadening material adds weight and cost. HALOsonic uses the engine RPM signal as a reference, which enables the EOC to generate a sound wave that is opposite in phase to the engine vibration induced noise. Error microphones are also mounted in the cabin of the car to provide feedback, refining the noise cancelling effects. By integrating EOC technology, the bulky materials usually used for reducing the transfer of noise can be minimised, resulting in vehicles which weight less, have lower fuel consumption and perform better overall.
3. International Electric Sound Synthesis (iESS)
As engines have become more quieter and more efficient, the driving experience has been negatively affected, creating a disconnect between the driver and the car.
HALOsonic’s iESS system emits a sound through the standard speaker system that is speed, acceleration and throttle dependent, allowing the driver to feel more connected to the car due to improved engine feedback. This sound can be customised to enable drivers to program the technology to emit any sound that a passenger may want to hear.
4. External Electronic Sound Synthesis (eESS)
As the number of EVs and hybrid vehicles on UK roads continues to grow, so does the risk of injury to pedestrians who are not able to hear the car approaching, due to their near silent running resonance. HALOsonic’s eESS creates an electronic sound that is projected from external speakers at the front and back of the vehicle, warning pedestrians that a car is approaching at low speeds.
The HALOsonic system is able to neutralise the unfortunate negative effects of using lighter materials and improving vehicle efficiency, which is often increased and unpleasant noise, while counteracting the lack of familiar audio cues in both Electric and Hybrid vehicles, which gives rise to significant safety concerns. HALOsonic allows these vehicles to adhere to future EU guidelines, while not compromising on driver enjoyment from engine audio feedback.
The technology could expand further claims HARMAN. When you sit in an electric car there is no typical engine sound and the car is more or less silent as it starts moving at first. The rolling of the car without any acoustic feedback tends to take people by surprise.
In such instances, OEMs typically can deploy a “welcome sound” to ensure the driver knows the car is good to roll. With the ever-increasing electrification now happening, a signature sound for these silent vehicles could be a predominant part of the differentiation and driving experience.