Signal-to-noise ratio is something audio engineers know all about. When they're designing an amp, a preamp, a network streamer or digital-to-analog converter, this measurement figure of the final product tells a lot of the story about what they're trying to accomplish.
This figure in audio is topical for us this week because it speaks to the wonder that is our hearing process, and it highlights a common part of it that gets compromised when our hearing is damaged.
Signal-to-noise refers to how much music is created versus how much noise. Noise is a fact of life for any audio engineer. All devices make some noise just by being electronic circuits that move power around, and the devices that amplify sound like preamplifiers and amplifiers also amplify their self-noise. So you can imagine that the lowest possible noise, or the highest ratio of signal to noise, is ideal.
When you've lost some of your hearing ability, your personal signal-to-noise ratio plummets. Common complaints from people with hearing loss center around being unable to hear a person talking when in the middle of a crowd, while loud music is playing or other situations where "noise" is high.
When that signal reaching our sound-processing region of the brain is diminished, the brain has to work extra hard to pick out the relevant sound from the noise. As I mentioned last week, many people suffer loss in the sound region that snare drums inhabit, and this is also around the region where a lot of human speech lives. ASL can be a wonderful solution when you can't communicate with speech, but I think it's safe to say the goal here is to not lose hearing that you already have.
So how do you know when something is too loud for your ears? Well, that's easy. Our hearing system is in touch with pain sensors whose only job is to tell us to turn the music down. Usually it is prolonged exposure, not transient exposure, to loud sounds that causes permanent hearing damage, but even brief bits of loud sound activate these nerves. Ensuring that you can hear speech and enjoy music well into your years is as simple as paying attention to how your ears feel and not ignoring the body's pleas for quiet.
I recently tested this by playing loud electronic music with strong snare-type sounds to it. While it was invigorating to listen at such a high level and really feel the music and be immersed in it, I did feel some pain and winced a little each time the snare hit. It was such a small wince that I could have kept up the volume and ignored the signs. But as soon as I pressed pause, I noticed my hearing was immediately fuzzy. The whole time I was listening, my nerves were yelling, "Turn it down!" and my brain's hearing-protection processes were actively trying to do so. I was just enjoying the music.
Just goes to show that it's far too easy and tempting to listen to music too loudly. Music is an amazing thing, and speech is so important, and all you need to protect your ability to experience both is to listen to your body.