Sound Quality of interior Active Sound enhancement

The automotive industry is in the fast lane to innovate and create new driving experiences. Transforming the internal combustion engine into an electrified drivetrain introduces new acoustic challenges. Electrified vehicles make hardly any sound at low speeds, which is dangerous for pedestrians and bikers. Next, to the driver inside the car, these vehicles lack feedback on the driving dynamics: they have a great acceleration, but this is not matched with an emotional acoustic feedback. Finally, new interior noises previously masked by the powertrain now become audible. Active Sound Design solves that by generating meaningful sounds on top of existing vehicle sound. State of the art methods include models that combine several layers of sound, either with classical order synthesis or with advanced methods as granular synthesis. These models are then parametrized in function of speed, torque, throttle, rpm, or other dynamic vehicle parameters, and then played over the speaker system of the vehicle. This paper studies the sound quality of several recorded interior active sound designs. It compares their subjective perception with objective sound quality metrics. Subjective perception is assessed both with a driver test as well as with jury testing in a listening room.