Continuing on last week’s theme, we want to help you understand how your hearing mechanism can become damaged, what the effects are of this damage, and most importantly, how to actively avoid this damage.
If you didn’t love music, you would not be reading this, and we want you to enjoy music for as long as you live. This information may be old hat to a few of you, but everyone deserves the chance to learn something new.
Two types of hearing loss can occur. The diagram above shows the regions that cause each type when damage is sustained. We will focus more on Sensorineural hearing loss since it is more directly related to exposure to loud sounds.
What Really Happens Inside the Ear of an Individual Who Has Suffered Hearing Loss?
Recall that our cochlea is lined with tiny hairs that vibrate proportionally to the intensity of the incoming sound, and various frequencies cause hairs at different positions in the cochlea to vibrate. Damage most commonly occurs in the Basal region, rendering one’s hearing less sensitive to the upper frequencies.
What happens that causes a reduction in hearing sensitivity in some frequency range?
The high-resolution photo below shows healthy hairs on top, and then we see those ugly buggers below. It doesn’t take a otolaryngologist to surmise that the hairs on the bottom would be less sensitive to sonic input.
How Loud is Too Loud?
First, let’s look at a typical chart showing the sound pressure level (SPL) of various everyday activities in dB, A-weighted. This one shows many events you may be familiar with and descriptions of the effects of the sound levels generated. No wonder people in the city are always yelling and that garbage truck wakes you up every Thursday morning!
The National Institute for Occupational Safety and Health has done a lot of research in the interest of minimizing hearing loss in workers across all industries. It has been determined that hearing loss reduces quality of life in a number of ways. But even more so to a golden-ear audiophile, or professional sound engineer/musician! Imagine a surgeon losing a hand, or a film aficionado losing his/her vision. Heartbreaking!
What does this mean to me? Well, these are guidelines for daily workplace noise levels, where lawsuits and mandated (expensive) hearing conservation programs are potentially at play. So to you engineers working long days in your AttackWall—pay heed! And to those of you enjoying a few hours of soothing HiFi in the evening, be sure to consider the other noise you may have been exposed to during the day. Your continued enjoyment of the music is at stake!
But I Wanna Rock!
Don’t worry, all is not lost. A-weighted sound level readings permit a little bit more “thump” than you might expect. And the exposure limits above as based on sound energy “dosage,” which can be moderated by controlling your running reverberant noise floor. Next week we’ll look at the way dosage is calculated and the ways to chip away at it using TubeTraps.
Don’t have a sound level meter as part of your tool kit? Pick up this inexpensive option to help keep an eye (ear!) on your exposure levels.