Hearing is important. After our sense of sight, it is the most important sense for navigating and responding to the world around us, it's one of the ways that humans pass along important communication, and it's a wonderful means of transferring information from "stuff out there" to "stuff in the brain."
As hunters and outdoor enthusiasts, it helps us to hear the call of the game we are chasing. It lets us know when two bucks are sparring and it lets us perceive the majestic, almost primitive sound of an elk bugling in the distance. We can study bird calls and learn about the dangers they are telling each other about. If a tree falls in the forest and we are nearby, it will produce a sound that we can hear (jury is still out on if it makes the same sound and nobody is nearby).
For these and other reasons, protecting your hearing is extremely important. In this guide, we're going to cover some of the science behind sound and hearing. We're going to dig into why we lose our hearing and what is actually going on inside that melon that sits on top of your neck. Finally, we're going to discuss the different types of hearing protection available. So strap yourselves in and if there is something you don't understand, just ask me to speak up!
You will see the terms passive and active come up quite frequently. Passive means that no electronics are used to block sound, active means that electronics are indeed used to block sound. Usually, this can make quite a difference in price.
Numbers and Definitions
Let's talk about Decibels. I know that you've heard the word, and maybe even awkwardly used it yourself on a few occasions to mean "Wow, holy &^*# this is so LOUD!" You're on the right track. It can have a few definitions depending on what you're talking about, but we're talking about sound. For our purposes, we're going to define it like this:
- Decibel - A measure of sound intensity on a logarithmic scale. The scale is logarithmic and the units used are dB. The zero point of the scale is referred to as the Threshold of Hearing.
- Sound Intensity - The power of the sound in the air at a given location. The sound intensity varies by distance from the point of the sound.
- Logarithm - The logarithm of a given number to a base defines the number of times the base must be multiplied to reach the given number. To say it another way, these are exponential functions, so when we say that decibels are logarithmic, it means that a small change in the number of decibels means a huge difference in the sound intensity.
- Threshold of Hearing - The lowest intensity sound perceptible to human hearing, also known as 0dB. (10-12; Watts/Square Meter.)
Let's take a look at how all of these things work together in an equation.
B is the total loudness in decibels, I is equal to the sound intensity (measured in watts per square meter) and Io is equal to the threshold of hearing (also measured in watts per square meter).
So what does it all mean to you, the person with the ears? It means that dB's increase exponentially with each added bit of sound intensity. The loudness that we humans perceive doubles with the increase of just a few decibels.
Ok, that's enough of the science stuff. In the next section, we'll take a look at what all of this means when we're talking about hearing loss.