Obtaining Head-Related Transfer Functions (HRTFs) is a challenging task, in spite of its importance in localizing sound in a 3D environment or improving the performance of hearing aids, among their various applications. In this paper, an optimized finite element method through adaptive dimension size based on wavelength (frequency) for acoustic scattering analyses using ANSYS is presented. Initial investigation of the validity of our method is conducted by simulating scattered sound field for a solid sphere exposed to a far-field plane sound wave at 100
(equally spaced in logarithmic scale) frequencies between 20 and 20k Hz. Comparison of the equivalent HRTF results between the two methods shows a maximum deviation of less than 0.6 dB between our method and the analytical solution depending on the angle of rotation of the sphere with respect to sound source.