One of my favorite events of the year is a string of Pioneer Day activities in Fairview, Utah. There’s a horse parade, a regular parade, an Idol-type singing contest and three events at the rodeo grounds—an ATV rodeo, a competitive rodeo, and a demolition derby.
All three of these events are fairly noisy on their own, but as the sound guy, I’m also standing a few feet beneath a battery of subwoofers. The ATVs are hit and miss, depending on individual engines; the rodeo’s music is wall-to-wall; and the demolition derby is outright cacophonic! If I had to guess (since I didn’t have my dB SPL meter at the time), I’d say a demolition derby gets up to ~147dB SPL for the main events, and they can last quite a while at a single stretch. It’s a little quieter if there’s some distance between you and the action.
Since 140dB SPL is the well-published threshold for immediate hearing damage, I packed some hearing protection for the entire weekend. For me, that meant $40 earplugs (Earasers Brand, Amazon link) that take off about 19dB without affecting any frequency band significantly more than another—a feature that allows me to still make fairly good judgement calls with my EQ, when needed.
The Skinny on Hearing Damage, in Brief
If you want an exceptionally-detailed and well-written article on this subject, Sweetwater published one not too long ago. You can also learn the basics of how the ear work on The Magic School Bus, Storybots and other well-make children’s shows. What matters most are some simple facts (taken from the aforementioned link):
Hearing damage may result from any sound above 80db. The recommendation given by the National Institute for Occupational Safety and Hazard recommends listening to 85dB SPL audio for no more than 8 hours in a day.
As explained in the page on sound, dB is a logarithmic scale that doubles power every 3dB. This corresponds with a halving of how long your ear will enjoy sustained exposure to subsequent doublings of pressure levels. You should listen to 88dB audio less than 4 hours a day; 94dB for one hour; 100dB for 15 minutes; 121dB for 7 seconds. Anything above 140dB will likely result in instant, permanent hearing damage.
All this damage is cumulative—a little hear, and a little there. A normal person will be exposed to machinery, screaming kids and extited fans, heavy traffic, loud music, forgetting to lower a volume knob before hitting Play, and many other routine sources that are too much for the delicate parts of the inner ear. There’s a point at which you start noticing you don’t understand people as often when they speak softly, or you’ll start to get a little ringing in your ear on occasion (tinnitus). If you go out hunting or attend a concert or derby, you might notice a significant difference right after.
We attended a house concert while our oldest was just a couple years old. It wasn’t long before I realized it would be too loud for our little one. Since I was there supporting a friend, I politely told him we’d have to leave if we couldn’t find hearing protection. He quickly produced a nice, kid-sized pair of over-ear hearing protectors.
Besides bringing ear protection to foreseeable events of questionable loudness, avoiding “fader creep” is a good way to protect yourself as well. The human ear has a feature that adjusts itself based on the incoming sound. It attenuates loud sounds and amplifies quiet ones. This is both for transients (quick volume spikes) and long listening sessions. For this reason, it’s normal for a passenger to turn up the volume in a vehicle repeatedly during a long trip. Similarly, if you’re mixing a song for long periods of time, you can get used to the sound and start to make bad decisions.
For both of these, the solutions are simple. For my car, I always turn my phone all the way up, then down one click, then set my stereo to volume 24 or lower (yours will likely be a different level). If it starts to sound quiet, I only turn it up a little farther if I know it’s a song that’s actually quieter than the previous one. Once the song is over, I go back to the original volume level. If I’m in heavy traffic and I can’t hear the music well, then I just accept it and keep driving.
For mixing sessions, you should mix at a comfortable level (perhaps 80dB loud sections), turn it up only occasionally to check specific things, and take breaks often (you should stand up and look somewhere >20ft. away for 20 seconds every 20 minutes or so to help your body and vision anyway). It’s also normal practice to check your mix the day after you think it’s finished; you’ll be surprised what you notice once you’ve slept away the strange things your temporary attunement fabricated.
Take care of yourself out there. If you don’t, like the cheater below, you could be benched long before you’re ready.