The “80/90 Rule”

I was riding the bus the other day; looking around at the passengers I noticed that most of them were plugged into some kind of MP3 player. Later that night I went to the gym, again I noticed a lot of people working out with their headphones on. The more I paid attention, the more I noticed that a large percentage of the population, especially the younger generation, are “plugged in” much of the time. But how much listening is really safe?

Audiologist Brian Filgor, of Boston Children’s Hospital, completed a study in 2006, looking at the output levels and usage of different MP3 players on the market.  The average iPod can put out as much as 110 decibels of sound! This is alarming considering that most conversational speech comes in at 50-60 decibels. Like other noise, music affects us by daily dosage. The louder the sound the shorter you can listen to it without risking damage to the auditory system. Any sound over 85 dBA (A-weighted decibels—a decibel scale that is used to represent the relative loudness of sounds in air when perceived by the human ear) can be damaging when listened to over an extended period of time (8 hours or more).

Based on this study and what’s known about safe daily listening dosages, Filgor and his group came up with an easy rule for safety when listening to MP3 players. Coined the 80/90 rule it suggests listening to no louder than 80% of the total volume output for no longer than 90 minutes at a time. One 90 minute listening session, which is an estimated 89 dBA, would give the listener about 50% of there daily dose of loud sound. If you like your music louder, reduce your time listening—vice versa—if you want to listen longer reduce the overall volume of the music.

Next time you’re jamming out on the bus (or anywhere else) or getting pumped at the gym remember to check the volume level of your music. Keep it at a reasonable level and keep your ears safe.

Sarah Nordberg, AuD is an audiologist at Affinity Hearing in Plymouth.  She may be reached at 763-744-1190 for any questions.  Affinity Hearing provides free hearing screenings and hearing protection consults to the general public.