This activity demonstrates the use of acoustic metamaterials (AMM) as a lightweight and compact solution for low frequency sound insulation. A demonstrative box was built as a previous MSc research project, where one side is designed to be able to house different materials samples. We aim to let you hear the differences in the sound insulation capabilities of AMMs compared with conventional treatments (such as a mass equivalent sample, or a material sample that is heavier, to achieve the performance of the AMM).