The characteristic test define the thiele-small parameters and the speaker is modeled to linear or non-linear model by thiele-small parameters. The performance test is carried out the sound quality by feeling test(subjective test) and objective test. The feeling test has many problems in a viewpoint of reliability, repeatability and preference that are related to judge. The study on the correlation between feeling test and objective test are carried out in some researches and introduce the loudness, sharpness, roughness and fluctuation strength. In this study, the loudness characteristics, which is related to sound quality, of the woofer speaker that are fitted to the domestic vehicle is investigated by measurement

In the car speaker, because the sound characteristics is changed by the space of car which mount the speaker, the speaker elements must be decide according to sound field. In this study, the mass of cone paper and damper is changed and the characteristics of the sound pressure and loudness are investigated by the experimental approach. According to the change of the speaker characteristics, the sound pressure and loudness level are changed. The effect of the con paper is larger than that of the damper in the aspect of the loudness. In the future, these data will be used to investigate the correlation between the sound quality and measurement data.

The sound characteristics is changed by the cabin of the car which mount the speaker. Therefore the speaker must be design to consider the cabin of the car. In this study, the mechanical components of the nonlinear speaker model are investigated by measurement. The frequency characteristics of the sound and the sound pressure level for the same size speakers which are adapted to domestic car model(semi-mid size & mid size car) are investigated, too. From the measurement, we can investigate the differences of the sound characteristics and the thiele-small parameter such as force factor, mechanical mass of driver diaphragm, mechanical resistance of driver suspension losses and mechanical stiffness of driver suspension. This means that the speaker design parameters are changed by the car model

The automotive speaker is modeld to nonlinear speaker model using the large signal performance measurement. In order to study the characteristics for the mass of cone paper and damper, the mass of the cone paper and damper is changed and the nonlinear parameters of the speaker are studied using the experimental approach. From measurement data, the effect on force factor, compliance(stiffness), resonance frequency, Q-factor is investigated by changing the conpaper and damper.