Fibers extracted from plant wastes can be used for sound absorption (SA) applications in vehicles due to its lightweight and porosity. The SA capability of raw areca fibers bundle (RAFB) as a function of the density and thickness of the test specimen is analyzed. Experimental results obtained using the impedance tube approach reveal that an increase in the specimen bulk density and thickness improves the SA capability of RAFB. Similarly, hollow air volume behind the sample enhances the SA in the lower frequency range. Theoretical results predicted using the Johnson–Champoux–Allard model match well with the experimental predictions. The ability of the RAFB to absorb sound is demonstrated to be equivalent to other commercially available natural and artificial fibers by comparing the results available in the literature.