The use of green materials for the acoustic correction of rooms

Green materials can be a valid alternative to traditional materials coming from the drilling of products of the chemical industry for the acoustic treatment of rooms. At the end of their useful life, they can be disposed of without damaging the environment. The use of green materials (e.g. hemp, brooms, freshwater canes or wood) can also be a valid alternative to traditional cropping systems that have become disused or unprofitable. In the present work, the values of the sound absorption coefficients of six materials obtained from the use of vegetable materials are reported. These materials were first dried and then appropriately shredded. In this way, a loose granular material was obtained, which compacted and packed inside jute covers can be used for the acoustic correction of rooms. The sound absorption coefficients were measured with the impedance tube in the frequency range 200 Hz - 2,000 Hz. The green materials analysed were cellulose, brooms, straw wood, hay, wood chips and cabuya. These materials have good sound absorption characteristics at medium frequencies, but at low frequencies, like all porous materials, the value of absorption is low.