Accurate characterization of thin cylinders - such as polymer filaments and metal wires - is important for enhancing the performance of new additive manufacturing (AM) processes which are developing with very high speed. This study investigates the circumferential resonance frequencies of metallic and polymeric cylinders subjected to normally incident plane acoustic waves, enabling the identification of their key elastic properties. Using a combination of analytical techniques and experimental methods, the acoustic wave scattering of both material types is thoroughly examined. The analysis uncovers a clear distinction: in aluminum cylinders, resonance frequencies emerge as minima in the form function, while in polymer filaments, they present as maxima. This contrasting behavior is validated through theoretical models and experimental measurements. Furthermore, the study examines interference at normal incidence, showing that the constructive interference responsible for resonances in the polymer filament appears as maxima (peaks) in the form function, whereas the destructive interference in the metallic cylinder manifests as minima (dips). This clear analytical and experimental demonstration of contrasting resonance behavior provides deeper insight into the acoustic properties of metallic and polymeric materials, thereby supporting improved material selection and quality control in AM applications.