Hearing and ipods Dr. Marshall Chasin, AuD., M.Sc, Reg. CASLPO, Aud(C), Doctor of Audiology

Noise and Music  Noise exposure is “almost like music exposure”  Prolonged exposure to 85 dBA will eventually cause a permanent hearing loss

Noise and Music  “Prolonged exposure…”  40 hours per week at 85 dBA  20 hours per week at 88 dBA  10 hours per week at 91 dBA  5 hours per week at 94 dBA  ….

Listening with one ear…  We all have a natural advantage when we listen with two ears. The music/speech is 6 decibels louder The music/speech is 6 decibels louder The music/speech is 10% clearer The music/speech is 10% clearer …. So, when listening with one earphone, the volume needs to be 6 dB louder (which is four times the damage). …. So, when listening with one earphone, the volume needs to be 6 dB louder (which is four times the damage).

Noise and Music  Nobody listens to music for 40 hours/week  BUT,… people do listen for 2 hours/day (ASHA sponsored Zogby International poll, March 2006) 1000 adults and 301 high school students 1000 adults and 301 high school students  AND, … depending on the volume setting, this may be equivalent to a damaging dose…

From M. Chasin (2006)

The 60/120 Rule The Fligor Rule (2006): Maximum settings to obtain 50% maximum dosage…  ipod volume at 60% for 120 minutes  Depends on earphone used Some earphones “isolate” the ear. Some earphones “isolate” the ear. Some earphones have different electro-acoustic characteristics. Some earphones have different electro-acoustic characteristics.

From Fligor (2006)

The 60/60 Rule  This is appropriate for CD players  These are about 3 dB more intense than ipods.  “60% volume setting for 60 minutes”

Portable music is portable…  The volume control is turned up in the presence of background noise  50% volume control may be comfortable in quiet, but this same comfortable listening level may be 80% volume in noise.

Portable music is portable…  The “best” headphone is one that isolates you from the environment…  You won’t need to turn up the volume control in a noisy place.  BUT, you also lose warning cues!  BEWARE!!!

Zogby International (March ’06)  69% would turn down the volume.  42% would listen to music less often.  36% would wear special (isolator) earphones.

So …  60/60 rule for CD players  60/120 rule for ipods  Use isolator earphones  BUT watch out for traffic!