Novel loudspeaker membranes based on nanofibrillar cellulose

Nanofibrils are the building blocks of wood fibres. They are characterized by high aspect ratio and high mechanical strength. In addition, they have the inherent property to adhere to each other and form strong networks. Nanofibrils is not yet a commercia l product, but expected on the market within short time. This new material represents new possibilities. A loudspeaker membrane is moving air in the audible frequency range, and ideally it should do this without any distortion. Membranes are today based on various materials and fibres based membranes are common. Important properties are e.g. high sound propagation velocity and high mechanical damping. Nanofibrils used in loudspeaker membranes have shown promising results with respect to these properties . The suitability of using nanofibrils in loudspeaker membranes, alone and in combination with other materials, will be investigated. A series of membranes produced from fibrils in combination with other materials will be manufactured in laboratory and f ull scale. The project consortium consists of experts on fibres and nanofibrils (PFI), acoustic properties (NTNU, acoustic lab and SEAS), manufacturing of fibre based membranes (YEN LUNG Electronic Factory), manufacturing of the loudspeakers (SEAS) and te sting of the membranes (Institute of Acoustic, Chinese academy of science). The laboratory membranes will be tested for various mechanical and acoustic properties. Based on the results a series of loudspeaker prototypes will be prepared and tested. If the results are promising, the project consortium is interested in continuing with more fundamental and thorough research and will apply for a main project.