Abstract :
The presence of machines in the industrial field often provides a sound noise effect. For
the purposes of reducing noise, sound absorber material is needed. The sound attenuation material
used can come from synthetic fibers and natural fibers. By utilizing composite technology and
special treatment, hyacinth rods are utilized as composites that perform to muffle sound.
The research method used is the Hand Lay-Up method. This study was conducted using
hyacinth fiber fillers using variations in filler volume fractions of 20%, 25%, and 30%. The results
obtained from the study were the addition of hyacinth rod fibers in polyester resin can improve the
ability of sound damping. The best damping capability was found in 30% hyacinth-loaded
composites with a Noice Absorption Coefficient (NAC) value = 0.366 at a frequency of 180 Hz.
Meanwhile, the best sound damping results in the 20% fiber volume fraction was (?) 0.288 with a
frequency of 120 Hz, and at the fiber volume fraction of 25% was (?) 0.324 with a frequency of
180 Hz, according to ISO 11654:1997 standards. In this test, the ideal composite material used as
a sound absorber material was a composite with hyacinth fiber of 30%.