The use of Glasswool as a commercial sound absorber is growing rapidly nowadays. Unfortunately, this material contains a high silica fiber which is harmful to human health. Herein, we present an improved preparation route of the composite material consisted of natural fiber made from Bangkirai wood waste (Shorea Laevifolia Endert) as a filler and unsaturated polyester as a matrix through hand lay-up method. The absorption testing, reflection, and sound transmission were performed by varying the volume fraction 0, 20, 40, and 60% of Bangkirai wood powder as a filler. It was obtained that the highest value of the sound absorption coefficient (α) contained in the composite with a 60% volume fraction, which is 0.49, which still approaching the Glasswoll as the standard frequency. The value is also included in the category of Sound Absorption Coefficient Class D with the range 0.30-0.55 based on ISO standard 11654. From the obtained results, this composite material has the potential ability to absorb sound in controlling noise and possibility as a commercial sound absorber.