 This article investigates the sound transmission and absorption performance of flax-fibre-reinforced polypropylene, PP, composites through experimental assessment of natural frequency and damping coefficient using modal analysis with an impact hammer, as well as vibrational analysis and sound transmission loss, STL, tests. The results show that thin FFPP composite panels have resonant frequencies ranging from 300 to 1000 Hz, which is consistent with the acoustic profile extracted from STL tests. Higher stiffness of FFPP composite may lead to higher STL at 100 to 400 Hz. The resonant frequencies of the composite range from 400 to 900 Hz and STL obeys the mass law with non-linearity in the range of 900 to 1600 Hz, providing a better insight into the performance of FFPP composites in vibro-acoustic environments. This article was authored by Kita Wang, Laquan NGAC Tram, Umea Kariman, and others. We are article.tv, links in the description below.