Introduction

As the technology of this world progresses, so does the repercussions of such quick developments. Amongst one of the more underrated consequences is sound. Below are the list of risks associated with sound pollution:

Hyperacusis, also known as noise sensitivity condition. People in this group are especially affected by noise pollution. It may affect their ability to focus and other physical or psychological conditions.
Otalgia, also known as ear pain. May occur due to one-time exposure to sound levels above 130 dB or long exposure of sound above 85 dB.
Besides the physical conditions, psychological repercussions such as drowsiness, aggression, anxiety and fatigue as a side effect have been reported. These side effects are worse for youths who would also experience memory loss, reading impairment and harm towards their psychological well-being.
Noise pollution can even pose problems to animals. It reduces habitat quality, increases stress levels and can mask other sounds. Animals that use sound for communication or hunting may be most affected by this issue. They may experience decreased patterns of foraging which reduces growth and survivability.

Boston University engineers had come up with a solution that could be applied to silent air travel. What is most intriguing about the product itself is its heavy reliance on the design structure. The product has a hole through the middle to allow for airflow. It relies on a specially designed horizontal spiral micro chambers within sound diffuser unit.

In our research, instead of embedding horizontal spiral micro chamber, we are exploring a much simpler design patterns that focus on the top surface pattern of the sound diffuser unit and study their impact on different frequencies of sound.

Experimental Setup

Computer > Speaker > Chamber with Difusser > Microphone > Computer > Analysis

The sound box used in this experiment was custom made in order to fit the diffusers on top. The cubic shape of the bottom part contains a speaker that points upwards, towards the tubular shape of the sound equipment. The rim of this equipment is where the 3D-printed models will be placed alongside a microphone that will be used to record the sound coming from the filtration.

Sound Difusser Designs in This Research

There are four different patterns that have been evaluated: control, right-triangle, long triangle, and cone. These patterns are placed to face the speaker. The microphone then records the amplitude of the sound and the results are displayed on a computer with an Igor Pro program, specifically designed for the experiment itself.

Final Product Result

From these individual points, it could be gathered that these individual patterns do have an impact on the sound. The two most effective patterns from these experiments seem to be the cone and the long spike patterns since both seem to have the lowest values (and do not amplify at some points) from the tables shown above. These conclusions can be made by comparing the control and the other forms of patterns and seeing which has the largest difference between the control and another pattern. When there seems to be a complete overlap of values, this does indicate how ineffective the patterns are at a certain frequency. These results do also show how the size of the hole impacts the noise that is filtered. Since there is more exposure to the individual patterns with smaller hole diameters, more sound is dampened in the process.

Future Outlook

It is possible that other patterns of interest could be explored through more experimentation and reflections on what traits may be more effective at dampening noise. A particular pattern that could be explored is the wavy pattern since it was probably the best performing dampener during initial tests. These tests then could be extended to real sounds encountered in the world such as cars and trucks.

Edelline Ayumi Sutanto

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