Sound Piercer
Sound Piercer is a streamlined headphone design with the purpose of reducing noise interference created from air drag. It is intended that by keeping background noise to a minimum, the user experience can be enhanced. Although active noise cancelling in headphones already exist, the effects of wind, especially at higher velocities, is hard to mitigate. The project therefore takes a more scientific approach, measuring the correlation between different forms and the design's air drag within a wind tunnel. It is to be noted that the project only encompassed the design of the headphone over-ear cup.
Ideation Phase
A target market of people aged 18-30 who use headphones in outdoor environments was established. Examples of outdoor activities of interest are running or walking in areas such as the beach where wind velocities are high.
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Research indicated that the cross-sectional area of the object is a significant factor in drag force. Therefore, different forms were explored through sketching, whilst also keeping the product relatively small. This was balanced with ergonomics research which indicated dimensions of headphone cup size for comfort. Hence, whilst applying streamlining and size reduction to the concepts, it was ensured that ergonomics was not neglected. Three of the concepts chosen are showcased on the second slide. It is to be noted that concept 1 was used as a comparative model with little to no streamlining or size reduction.
CAD and 3D Printing
The concept sketches were then recreated using Solidworks. The CAD files would then be used to 3D print prototypes at a 1:1 scale. These models would then be used in a wind tunnel to determine the drag force and drag coefficient of each design.
Wind Tunnel Testing
Each of the three models were placed in a wind tunnel for testing. The drag force in Newtons were then recorded at wind velocities of 4, 6, 8.1, 10 and 12 metres per second across three trials. The tabulated averages can be seen in the fourth photo of the slideshow. Concept 3, 2 and then 1 had the lowest drag forces respectively. Using the drag force formula, the drag coefficient of each of the designs were calculated. As expected, the concept 3 was most efficient, followed by 2, then 1.
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The difference between 2 and 3 against the comparative model 1 is significant. Therefore even at a smaller scale of headphones, a difference can be seen in drag force through streamlining and size reduction. Although concept 3 was most efficient, the difference between concept 2 was relatively small. Based on aesthetics and marketability, it was determined that concept 2 would be most effective if pursued commercially.
