Vehicle audio system performance is an important attribute for final costumers. In this sense, its evaluation is an important aspect for selecting the design and validation process for automobile manufacturers. Usually the vehicle audio system performance is evaluated only by subjective judgment. However the design requirements demands objective measurements to set targets establish benchmarking and apply refinements to the design. Thus, in order to evaluate and improve sound system performance, it has been established a subjective evaluation process on reproducing and analyzing customer perception in a more reliable way. To support this information, objective evaluations have been used based on total harmonic distortion (THD), normalized frequency response (NFR) methods and spectrogram, which have been shown as straight and fast objective tools. Reinforcing the objective evaluations, qualitative time-frequency spectrogram has been used.