Presented at the 15th International Conference on Auditory Display (ICAD2009), Copenhagen, Denmark, May 18-22, 2009Quality investigations and design of interior car sounds constitute an important challenge for the car industry. Such sounds are complex and time-varying, inducing considerable timbre variations depending on the driving conditions. An interior car sound is indeed a mixture between several sound sources, with two main contributions, i.e. the engine noise, the aerodynamic and tire-road noise. That’s why masking phenomena between these two components should be considered when studying perceptive attributes of interior car sounds. Additive synthesis is used to simulate the harmonic engine noise. Nevertheless, this synthesis is controlled by a large number of parameters and no relation between these parameters and their perceptive relevance has been clearly identified. By combining sensory analysis and signal analysis associated with an auditory model, we can find a relation between a reduced number of signal parameters and perceptive attributes. This study develops a method to simplify the timbre description of interior card sounds and presents the first results of auditory model application on such sounds