| Category | EMNC | P13 | Wind Noise Reduction Device for the Hearing Impaired |
| Abstract | The research goal was to provide a device that reduces discomfort due |
| to wind noise experienced by hearing aid users while riding a bike. The |
| device reduced the noise while allowing important surrounding |
| background sound such as cars, sirens, and other motor vehicles to be |
| heard. Three testing methods were configured; a bike rig with a false |
| head and a microphone in the ear, a wind tunnel with a microphone in a |
| false ear, and finally a wind tunnel where the microphone was placed |
| above the ear, as it exists in behind-the-ear (BTE) hearing aids. The |
| third method was then used to draw data, results, and conclusions |
| from, as the first two failed at producing conclusive results. Sound was |
| recorded for a minute for each combination of test parameters. Each |
| test condition was repeated with a whistle noise to replicate an |
| emergency vehicle siren. Various materials were then used to block |
| sound but still allow for the siren-noise replica to pass through. These |
| included: a control group with nothing blocking the ear, blue high |
| density foam, a replica of a preexisting product Cat Ears, kitchen |
| sponge foam, and speaker foam. Three fan speeds were also used: |
| low, medium, and high. The head was oriented at three angles: forward, |
| toward the ear (left), and away from the ear (right). An open-source |
| program, Audacity, was used to analyze decibels as a function of time, |
| and then decibels as a function of frequencies (hertz). These were |
| plotted based on the microphone’s reference sound and then replotted |
| on the a-weighted curve of human hearing. There was no difference |
| found in the left and right facing data, so that was disregarded when |
| analyzing and only front-facing data was used. Though all materials |
| were effective to some extent, it was determined that the speaker foam |
| worked the best across all three fan speeds allowing for necessary |
| sounds to pass through but blocking wind noise. The control group with |
| nothing blocking the ear performed the worst. The research goal was |
| met due to the success of the materials used in reducing air turbulence |
| around the microphone. |
| Bibliography | http://www.cat-ears.com/how-they- |
| workhttp://www.phys.uconn.edu/~gibson/Notes/Section5_2/Sec5_2.htm |