In late years, the noise by speeding up vehicle in the car increases, and spoil comfortable environment in the car. In the inside of car , the noise of 100〜2500 [ Hz ] is the problem . This study's theme is Noise reduction in such a high speed vehicle by using a lot of Micro - size granular materials. An experimental device is a vibrating machine furnished with the measure of iron to which the cylinder was attached. I put the inside granular many materials of this cylinder. And I vibrate equipment and count the resonance frequency of a measure. And I choose the particulate material reducing vibration of the frequency. In this study, the granular material reduced up to about 9[dB] vibration in a low spectrum.
