Today, on the world market in addition to the well-known synthetic fibers, occur more and more composites reinforced with natural fibers such as flax, hemp and jute. According to this, new research programs are established with the task of a constant improvement of the properties of biocomposites, and a general incensement of functionality and competitiveness. The main advantage of composites reinforced with natural fibers compared to synthetic composites is related to sustainable development, especially in the case when some biodegradable composite matrix is used as well. The use of biofibers and biomatrices for the production of “green composites” reduces the energy consumption related to the production of synthetic fibers and resins, reduces the accumulation of non-degradable composite waste, promotes the development of agriculture in general and the implementation of new, alternative ideas. In addition to these advantages, composites reinforced with natural fibers are characterized by less weight compared to synthetic composites and very good acoustic properties. For this reason, in this paper the prototype of the drum shell reinforced with flax fibers in biodegradable cashew nut shell liquid (CNSL) polymer matrix is made. Afterwards, test tubes were made and mechanical properties of composite material were tested. In conclusion, acoustic properties were tested.