Just an FYI to people about the amount of noise coming out of your IEM. If I did this experiment incorrectly please let me know because my results are surprising and might serve as a caution regarding IEMs and hearing loss.
I used a decibel meter to measure the dbA (slow) entering the ears from (a) my shure SE425 IEMs, (b) a variety of open and closed back headphones (the brands do not seem to matter as they were all similar in result). This was with the headphone plugged into my MP3 player. I did this because I was determining the proper volume with which to listen to the IEMs.
0 bars of volume (no sound from the player) -- as expected all put the same decibels of sound into the ear canal, about 57 db (I might have some room noise, by the way, as the window was open)
1 bar of volume -- IEM, +3-4 decibels (60-61 decibels total); over the ear headphones (no change in decibels)
2 bars of volume -- IEM + 6-8 decibels (63-65 decibels total); over the ear headphones (no real change)
3 bars of volume -- IEM + 11-14 decibels (68-71 decibels total); over the ear headphones (no real change)
the over the ear headphones didn't reach 60-61 decibels until I moved the volume up to 5 bars (around where I normally listen to them). they didn't reach 63-65 decibels until I moved it up 8 bars (I very rarely listen to the over the ear headphones at this volume). They didn't reach 68-71 decibels until I moved the volume button way up to a level at which I never play them (although I have occasionally played the IEMs at that level not realizing quite how loud they were).
at maximum volume, the over the ear headphones were putting out 80-85 decibels at the ear, but the IEMs put out 100-110. it would be really hard to damage your hearing with an over the ear headphone and this mp3 player, but you can easily do it with an IEM.
I think this is why audiologists blame IEMs for hearing loss, relative to speakers or over the ear headphones. You can turn your speakers up really loud, but the amount of db actually going into your ear canal won't be that high. Same with over the ear headphones. But with IEMs, you're pumping very loud decibels right into your ears often without realizing it.
Edited by ag8908 - 2/16/14 at 8:13pm