Investigation into MP3 player noise levels when using noise cancelling headphones

Abstract

In the last 5 years the prevalence of the iPod/Mp3 players has grown exponentially. The use of devices with in-ear earphones under urban conditions has been reported widely in the press anecdotally and researched recently. This study compared listening levels for 20 test subjects under quiet conditions and that representative of a London Underground train journey. Calibrated recordings of underground trains running in tunnels were played through a loudspeaker in an anechoic chamber, whilst pop music, rock music or speech podcasts were played through Bose noise cancelling headphones. The noise levels were measured using a Binaural Head and Torso. The participants had time to adjust the volume to a comfortable setting on each occasion. Results showed that the listening levels were significantly lower using the Bose headphones than with the supplied in-ear earphones. Only 10% of subjects listening to the rock music at levels above the upper exposure limit based on 1 hour of listening.