A rally car must be acoustically perceptible on a special stage to ensure the safety of spectators and officials. This also applies to electrically driven vehicles, whose volume is naturally much lower than that of conventional rally vehicles. For this reason, the new Opel Corsa-e Rally must have a sound system.
The hardware must be particularly powerful and robust for use in rallying. However, for an electric rally vehicle to be heard well by spectators, the speakers must be mounted outside, where they are fully exposed to vibrations, dust and moisture. So, the Opel engineers searched for highly durable speakers.
They found what they were looking for in marine accessories. At the front and rear of the Corsa-e Rally there are now two splash-proof loudspeakers each with a power consumption of up to 400 watts. They are supplied by an amplifier that receives its signals from its own control unit. This black box operates with specially written software that converts the vehicle data. The system is rpm-dependent, which therefore makes spinning wheels audible. The tuning of the final sound pattern took several months. The software was continuously developed and is now based on a stationary “idle sound” that can be adapted to all speed ranges.
That´s how Rally Cars of the Future sound like
The volume can be adjusted in two power levels. When driving on public roads between competitive stages, a quiet mode is used. The volume is turned up fully only on special stages. The regulations require the teams to adjust the volume accordingly.
“We did not want to simply simulate the sound of a combustion engine, but create a unique electric sound that suits the project”, says Opel Motorsport Director, Jörg Schrott. “We are pleased with the result and convinced that the sound will also excite the fans along the special stages, even though it is deliberately different from that of a classic rally car with combustion engine.”
The Corsa-e Rally with its unique sound system will make its debut on May 7-8 in the opening round of the ADAC Opel e-Rally Cup, the world’s first one-make cup for electric rally cars.