Keeping your ears happy and healthy? November 21, 2008
Posted by ConnorSmith in : Acoustics, Chit Chat, Project Studio , trackbackHow loud can you listen to music?
Working in an industry where it’s your job to listen to music all day, knowing the safe limits of our hearing system is really important. You only get one set of ears, they need to last!
The ears can safely listen to a WIDE dynamic range of sounds. However, the duration of this “safe” window decreases rapidly as sources increase in volume. Many of us in the audio industry will be listening for the better part of a whole workday (say 8 hours at least), so its good to know how loud we can listen without damage. The problem is that everything sounds better when its louder.
OSHA (the Occupational and Safety Health Administration) is a federal organization dedicated to safety in the workplace. OSHA has generated a list of dB ratings with associated time durations which will not damage the hearing system. Unfortunately, these figures are sometimes disputed. OSHA first outlined that it was safe to listen to 90 dB sound for 8 hours per day. However, many audio professionals think that the number should be 85 dB.
In my opinion, its better to operate on the safe side (right?), you won’t miss those extra 5 dB. There is some debate on how long to listen to music at certain SPLs. Taking in account factors such as the natural compression of the middle ear, the duration of breaks, spectral content of material, how our ears deal with loud sounds (vs. soft sounds), etc. can factor into these numbers (as well as the weighting of the SPL meter). Here are some basic guidelines for listening levels (each of these being “per a 24 hour period”):
- 8 hours at 85 dB
- 4 hours at 93 dB
- 2 hours at 100 dB
- 1 hour at 105 dB
- .5 hour at 110 dB
- 15 minutes at 115
- Anything higher, get out immediately!
Also remember, these are over a 24 hour period. Once you listen to 15 minutes of ~115dB music, you need to shut your ears off from the world for 23 hours and 45 minutes to ensure no damage occurs.
Another good thing to keep in mind is that relationships between decibel levels are logarithmic (not linear). So if you jump from 50 dB to 110 dB, thats not 2.2 times louder, its 1,000,000 times louder (ONE MILLION!). Crazy huh?
The moral of the story: buy an SPL meter and use it!
SPL meters are inexpensive, and can save your ears. Keep one by your mixing desk and check it occassionally throughout the day. Its also good to calibrate your listening system so that you know where certain levels are located on the knob (relatively close obivously). Setting your “normal volume” to around 80dB will ensure that you are safe for the whole day.
Anyone working in a studio knows that sometimes during the day, its time to listen to the song really loud once through (not only to pump the band up, but also to hear what the song sounds like at that volume). This is fine! Just make sure it doesn’t drift above 100dB too much, and that you substitute some sub-80dB listening in parts of the day to make up for it.
More on SPL meters and decibel ratings in the future. Any quesitons? Post them here.
C
The Studio Files
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