An acoustic design project for final year engineering students using resonant arrays

Abstract

This paper reviews the creation of a design course for mechanical engineering students at the University of Auckland. The primary objective of the course is to introduce students to the field of acoustics, teaching basic theoretical and experimental acoustics principles, together with product design and fabrication methods, in an engaging and educational manner. During the course, students were assigned the task of developing a noise reduction duct jacket that reduced sound propagation whilst allowing free airflow, all within specified dimensions. Students were required to create designs that attenuated a predefined sound spectrum, with both narrow-band and wide-band components. Over six weeks students developed their designs using mathematical modelling and fabricated their prototypes. The performance of their suppressors was assessed through sound pressure level and impedance tube transmission loss measurements. Students then modified their designs to maximise performance before final submission. Four-person teams produced a diverse range of implementations. The most successful designs achieved impressive performance with peak transmission loss up to 70dB, 2kHz bandwidths of 10 + dB transmission loss and a delta dBA reduction of 21.5 dB. Student feedback indicates a high level of satisfaction with the course, highlighting its effectiveness in imparting key knowledge and skills in acoustics engineering.