According to Delphi, the generator is available in two different versions. Due to their programmability they can meet future legal requirements even though the related discussion has not been completed yet.
The generators automatically are activated when the vehicle's own noises fall below a certain level, for instance because of low speed. The two versions obtainable differentiate themselves through the way the electronic vibrations are transformed into audible noise; customers can choose between a piezo-based sound transducer and an electrodynamic one. According to Delphi, the piezo-based version weighs only one third of a conventional multi-module system, and it consumes 90 percent less energy. Its audio spectrum covers the range from 500 Hz to 10 kHz. The electrodynamic version features a broader spectrum; its frequency range goes down to 150 Hz.
Both systems are programmable; customers can generate sound sequences indicating their brand identity. They consist of a 32-bit microprocessor with flash memory and a class-D amplifier. An interface connects them to the vehicle's internal data bus. The systems are designed for operation in rough environments, Delphi said.