Assessment of Acoustic Properties of Synthetic and Natural Materials Using an Angular Sound Reflection-Based V-Tube Test Rig

Abstract This study presents the development and application of a novel V-shaped test rig designed to evaluate the acoustic performance of materials based on the principle of angular sound reflection. The rig overcomes limitations of traditional four-microphone impedance tube methods, enabling testing of larger, molded, or irregularly shaped materials at frequencies as low as 500 Hz and extending to higher frequencies. Validation of the test rig was achieved through a combination of experimental measurements and simulations using va-one software, demonstrating close correlation and reliability in predicting sound transmission loss (STL) and noise reduction (NR) performance. The validated rig was used to investigate the acoustic properties of five materials, including synthetic and natural fiber-based samples. Results revealed that polyurethane foam, with a thickness of 25 mm and a density of 45 kg/m3, exhibited the highest STL and NR performance among the synthetic materials. Notably, cotton, a lightweight natural fiber material, demonstrated superior noise reduction capabilities despite its lower thickness of 20 mm, highlighting its potential as an effective acoustic material. This research establishes the novel test rig as a versatile and reliable tool for advancing acoustic material testing and contributes valuable insights into the acoustic performance of different materials.