Huimin Ji

Publication Date


Document Type

Honors Thesis




MP3 players, Headphones, Sound analyzers, Deafness, Noise induced, Sound exposure, Noise induced hearing loss


A common risk factor for hearing loss in children and adolescents today is the use of earbuds to listen to music on portable audio players. The concern of hearing impairment caused by MP3 headphone usage has increased over the past decade. Survey-based studies concerning this issue have been conducted, but few quantitative studies exist. A senior honor thesis began work to characterize the noise exposure from an MP3 player within a college-aged population through measurements and quantifying the damage MP3 headphones might cause to adolescence's hearing. A prototype of the data acquisition system consists of a Parallax microcontroller, an analog to digital converter, a microphone and a card adapter for a MicroSD card was built. The operating algorithm was developed in Spin language. The functionality of the system was validated by analyzing the output of analog sinusoidal input signals of di erent frequencies and amplitudes. This study improves the prototype developed by Draghici and applies it to collect data from the microphone signal input for music output from MP3 earbuds in-situ. The logic and algorithm for data storage are optimized, and the improved system requires 3s to write 0.4s continuous data to the MicroSD card. A Matlab program is developed to analyze the collected data from MP3 earbuds and calculate the sound exposure. The improved data acquisition system is tested by analog sinusoidal input signals from a function generator. The behavior and linearity of the microphone is validated by analyzing 1kHz pure-tone sound input at amplitudes ranging from 100mV to 2V. An excerpt of music is played at 1/2, 3/4 and full volume with the author's iPod Player coupled to a cavity to validate the response of the data acquisition system to real music; the same excerpt of music is played at 1/2 and 3/4 the maximum volume from the iPod Player in the author's ear to calculate the actual sound levels.




52 p. : ill. (some col.) Honors project-Smith College, 2013. Includes bibliographical references (p. 44-45)