The EU ‘Regulation on the Sound Level of Motor Vehicle’ (EU 540/2014) in combination with EU Requirement ECE R138, will ensure such vehicles are more easily heard by pedestrians, cyclists and vulnerable groups and follows more than a decade’s worth of campaigning by groups such as the European Blind Union.

The regulations state AVAS shall be activated for vehicle speeds up to 20km/h, with a minimum sound level of 56dB; equivalent to the sound level of an electric toothbrush or paper shredder.

The legislation also dictates the AVAS sound ‘should be a continuous one providing the vehicle driving behaviour to other road users and pedestrians.' For example, generating changes in sound level and pitch to signify acceleration.

Since 2009, acoustics expert HARMAN has been developing its own AVAS system called external Electronic Sound Synthesis (eESS) under the HALOsonic active noise management solutions portfolio, thereby helping a number of OEMs adopt the technology ahead of the deadline.

Drawing on over 60 years’ of audio expertise, HARMAN’s eESS creates a specific sound that is projected from speakers positioned at the front and rear of the vehicle. Speed and throttle position sensors determine the volume and characteristics of the eESS signal warning pedestrians of an approaching vehicle.

Although not mandated by the EU legislation, HARMAN’s system is also modular to offer in-cabin sound to provide acoustic feedback on vehicle status thereby ensuring the driver is more connected to the vehicle.

For example, the welcome sound when the electric motor kicks-in or the shutdown sound when the motor is switched off, provide the driver with acoustic cues, which otherwise would not be present in an EV. Moreover, eESS can be tuned to meet customer specific requests and/or comply with market specific regulations, such as in the US where eESS should be active even at speeds of 30km/h.

Additionally, HALOsonic lets carmakers create custom-designed sounds, thereby helping OEMs have a sound-signature that reflects the brand DNA of their cars. “Be it a sporty engine sound or a spaceship-like drone sound, HALOsonic is proud to be a key enabler for OEMs in their pursuit to stay a class apart without compromising pedestrian safety,” concludes Augustine.