It is necessary for vehicle horns not only to satisfy regulations on the sound level but also to fulfill various demands related with sound quality. For example, a disk type horn which is attached on most of small size vehicles has been required to improve its sharp feeling sound. However, the improvement of horn sound has been deterred mainly due to the deficiency of the understanding on how design factors are related with emotional judgments on horn sound. In addition, a proper CAE tool is not available in the process of horn design since it is difficult to describe multi-physical phenomena engaged with horns. The purpose of this study is to improve the sound quality of a disk type horn. In order to achieve this goal, firstly, acoustic characteristics of horns were obtained through a series of experiments. In addition, various sound quality metrics were examined in order to derive design factors affecting sound quality enhancement. It is found out that the sound peak distribution is a crucial factor to determine the performance of disk type horns. Secondly, vibro-acoustic simulations were carried out in order to predict sound pressure levels of vehicle horns in the frequency domain. The correlation between tests and simulations was investigated for the verification of newly suggested CAE methods. Thirdly, a new concept of a disk shape was suggested which can improve the sound quality of horns by increasing sound peak levels in specific frequency ranges.