Evaluating the maximum playback sound levels from portable digital audio players

Abstract

To assess the maximum sound levels that may be experienced by young people in Canada from modern digital audio players, this study measured nine recent models of players and 20 earphones. Measurement methodology followed European standard BS EN 50332. Playback levels ranged from 101 to 107 dBA at maximum volume level. Estimated listener sound levels could vary from 79 to 125 dBA due to the following factors: (i) earphone seal against the ear, (ii) player output voltage, (iii) earphone sensitivity, and (iv) recorded music levels. There was a greater potential for high sound levels if intra-concha "earbud" earphones were used due to the effect of earphone seal. Simpler measurement techniques were explored as field test methods; the best results were obtained by sealing the microphone of a sound level meter to the earphone using a cupped hand and correcting for the free field response of the ear. Measurement of noise levels 0.25 m from the earphone showed that a bystander is unlikely to accurately judge listener sound levels.

MP3 player listening habits of 17 to 23 year old university students

“…The suggested guidelines put forth by Portnuff and Fligor ͑2006͒ regarding maximum listening time per day based on the NIOSH ͑1998͒ damage-risk criteria state that no limit to listening time is necessary at up to 50% of maximum volume regardless of earphone type used, which would apply to about 8 of our 28 subjects. Although they have value, these proposed listening limits do not factor in earphone fit, stimulus ͑e.g., music͒ level or device properties when using earphones other than those supplied with the device, which have all been shown to have an influence on the sound levels recorded from digital audio players in a study by Keith et al ͑2008͒.…”

“…Beyond their maximum output capabilities, newer generation portable digital audio players are also characterized by numerous features that make them potentially riskier than older portable audio devices, such as the aforementioned portable compact disk players. For instance, increased music storage capacities, longer battery life, and easier portability make it more convenient to listen to digital audio players for extended periods of time ͑Hodgetts et al, 2007;Keith et al, 2008͒. These factors have led to speculation that noise-induced hearing loss may be developing into a substantial health concern for today's youth due ͑in part͒ to excessive noise exposures from use of these devices ͑Daniel, 2007; Vogel et al, 2008 There is some research suggesting that teenagers and young adults demonstrate symptoms of noiseinduced hearing loss. Specifically, 15.5% of adolescents aged 12-19 years had threshold shifts displaying a notch pattern commonly associated with noise exposure in one or both ears ͑Niskar et al, 2001͒ and in the research by Chung et al ͑2005͒ the majority of young adults have experienced tinnitus ͑i.e., phantom rushing, buzzing, ringing in the ears͒ and hearing impairment after loud music exposure.…”

Comparing two methods to measure preferred listening levels of personal listening devices

“…However, the alarm regarding the recent generation of PLDs was perhaps justified based on the capability of these devices to store more music and play the music back at hazardously high sound pressure levels ͑Fligor and Cox, 2004, Keith et al, 2008͒. Objective measurements of preferred listening levels using modern-day PLDs have been missing from the debate.…”

Short-term Auditory Effects of Listening to an MP3 Player

“…Previously, A-weighted free-field maximum SPLs measured using an acoustic manikin reached 101 to 107 dBA for MP3 players. 5 Also, the maximum SPLs for an MP3 player with earbuds reached 110.5 dBA. 4 It is, however, not clear whether this maximum level was determined by the device or the maximum tolerable level for the author.…”