Noise Reduction By Straw

Silencer made from carpet? It happens. But, what if a silencer is using materials previously considered waste, like straw? In addition to muffle noise and make you comfortable hearing room, the use of materials it also has the spirit of recycling. Not cool ....

Budi Santoso, and Elise Novita Sari Kartika Sari, students from SMK Boedi Oetomo 2 Gandrungmangu, Cilacap, Central Java trying meniciptakan silencer made from rice straw. "We feel, rice straw is abundant in our area, but less effective utilization.'s Why we use the straw for a silencer," said Elise reveals reasons for establishing a silencer made from rice straw on Monday (11/22/2010) in Depok.

Researchers recognized the teenager, creation-based sound absorbers is not the first straw. "Before, nobody ever made a silencer made from straw, but use a cement adhesive, so heavy. Here, we use the glue from starch materials and resins," said Elise reveals the novelty of the research.

To do so, Elise and colleagues gather hay and dry them first. Once dry, hay was cut into small pieces. Furthermore, the straw is mixed with adhesive material, there are also mixed with starch mixed with water, some are mixed with resins that are mixed with chloroform.

The number of straw mixed with an adhesive adapted to the size of a silencer that will be created. For the size 10 x 10 cm for example, the amount of straw required is 100 grams. "Once mixed, a mixture of straw and adhesive material printed, can be spherical, can also form or another box. Then, this material is in-press with a press," said Elise describes the next step.

Elise has been testing the effectiveness of the silencer is made from straw. He uses a wooden box with a hole at the top. Upper holes are then connected with a small pralon pipe. Part wooden box filled with the sound source and the center of the pipe is filled with a silencer made from straw. Furthermore, measurements with a straw vote after muted done using a tool called Sound Level Meter.

"To a mixture of straw with starch, sound absorption coefficient is 0.27. If a mixture of hay with resin, absorption coefficient is 0.51," said Elise. That said, the noise generated by the sound source is reduced about 27 percent and 51 percent. If the absorption coefficient is 1, then no more sound from the source of noise is heard. When kompas.com try this tool, the volume is reduced, but the sound is still audible.

Then, where this tool should be applied? Budi Santoso said, "Can be installed in a wall or on the inside of a car for example." He explained that the straw could be placed on the car top and sides, then coated with materials such as fiber to close it. Straw material can also be used to make the room soundproof, sound dampening material to replace the existing.

Asked about the amount of hay needed to coat the inside of the car, Budi said his team was not ready to apply to that extent. According to him, still need further steps to make it happen.

The idea of making a silencer of hay were presented at the Scientific Work greedy Teenagers held 42nd Indonesian Institute of Sciences (LIPI) in Depok, West Java.