Analysis of Factors Affecting Output Levels and Frequencies of MP3 Players

Abstract

Exposure to high levels of music that could lead to music induced hearing loss (MIHL) has been of recent interest especially for young adults, considering their excessive use of personal listening devices such as MP3 player. More attention should be drawn to MIHL for noting that early noise exposure leads to earlier onset of presbycusis. In search of appropriate and safe listening habits for young adults, this investigation was aimed to evaluate output levels and frequencies generated by the Samsung galaxy note MP3 player depending on two earphone types; ear-bud and over-the-ear earphones and three music genres; rock, hip-hop, ballade. A sound level meter was used to measure output level and frequency spectrum between 12.5 and 16000 Hz at all 1/3-octave bands. The following results can be summarized. 1) The earphone styles did not produce significant difference in output levels, but the music genres did. However, the results of music genres varied. 2) Neither earphone styles nor music genres produced significant difference in frequency response spectrum, except music genres at the volume settings we usually listen to. Additionally, volume levels should be lower than 50% for usual listening situation. Through this investigation, it was noted that the frequency range was substantial between 50 and 1000 Hz regardless of the styles of earphones and music genres, implying that we should be cautious of this frequency range when we listen to music. Researchers should give more attention to the effects of the mixture of output level and frequency spectrum, considering that the auditory system has frequency specificity from the periphery to the central to provide refined methods for protecting our ears from MIHL.

Keywords: Frequency spectrum; MP3 player; Music induced hearing loss (MIHL); Output level.

Fig. 1

Bruel & Kjaer Type 2250 Light sound level meter and 2/6 CC coupler.

Fig. 2

Z-weighting output levels in dB SPLs as a function of 1/3-octave frequency bands at two volume settings, #15 (solid line) and #8 (dotted line), and two earphone styles, the ear-bud (open symbols) and over-the-ear (closed symbols) earphones for three music genres. SPL: sound pressure level.