Investigation of the sound-absorbing performances of pure coffee grounds

Various natural sound-absorbing materials such as rice by-products, coir fiber, date palm peanut husks, hardwood cross-sections, and forest by-products have been introduced to replace petroleum-based in previous studies, their performance was significant. This study investigated the of pure coffee grounds an eco-friendly material. After inserting into cylindrical holders with lengths 20, 30, 40 mm, density adjusted from 0.2 0.5 g/cm3. Then, sound absorption coefficients were measured by impedance tube. As thickness increased, coefficient at low frequencies improved. However, high decreased. The optimal noise reduction (NRC) this 0.61 a 0.3 g/cm3 50 mm. result shows that is comparable other materials. concludes use-value