How to deal with unsuspected source of annoyance in electric vehicle cabin using the "sonic augmented" concept?

The disappearance of the main source of noise with electric vehicles resulted in a breakthrough in car cabin sound experience. Despite significantly lowering the sound level pressure, one cannot claim perfect quietness is achieved. Indeed, as the auditory masking produced by the internal combustion engine is not effective anymore, unsuspected sounds such as electric whistling, whining or switching are now part of this sound environment and may be identified as unpleasant sounds. However, drivers' expectations are to have audible feedback indicative of vehicle operation that matches their expectations. Therefore, the presence of unwanted and unpleasant sounds, on the one hand, and the absence of desired and informative sounds, on the other hand, is an opportunity for sound design to create a new sound environment inside car cabins. The present work proposes a "sonic augmented" concept based on the idea of adding designed sounds, called "masks", participating both in the overall soundscape augmentation and in the attenuation of unpleasant sounds, called "defects". Sound design strategies with different parametrizations will be presented, as well as the results of two perceptive experiments whit the aims at evaluating the impact on perceptive attenuation of "defects" and the overall sound quality.