According to the Pew Research Center, by 2018 95% of all Americans have a cellphone. And three out of four of us now use smartphones. That includes nearly half of codgers like me, who are older than 65 years of age.
So what does this have to do with protecting our hearing? More than you may think!
First, consider the volume you’ve set for your phone to play back into your ears. Like any other sound source, if it’s too loud, it can damage your hearing.
Perhaps you’ve set your phone’s volume level at the highest setting, to permit you to hear a conversation against a backdrop of loud noises, whether you happen to be in a shopping mall or while driving your car. Okay, but why not reset that volume level lower when you’re not in a noisy environment? It’s easy enough to do with most phones; just use the “Settings/Sound and Notification/Volume” buttons to change things. Some phones even feature external buttons that let you reset volume levels quite readily.
How loud is “too loud”? Again, that depends. It’s safest to say that you should set the “base volume” on your phone to the lowest level that’s easily audible while you’re in a quiet environment.
In previous postings in this series on “Defensive Listening” (for example, https://www.earglasses.com/blog/2016/06/), we provided information on the absolute levels of ambient sounds that could produce hearing losses over time. We suggested that careful readers acquire a sound pressure level (“SPL”) meter in order to determine for themselves what kinds of hazards their own aural environments might pose to their hearing. But with the demise of Radio Shack, inexpensive SPL meters have become harder to find.
But now for the good news: “there’s an app for that!” And better yet, they’re all free.
How can that be? These apps use the microphone in your smart phone to measure SPLs. All you have to do is go the Google Store if you use an Android OS phone, or to the iPhone App Store and choose from among a number of programs. Download and install your choice of app, and start using it to measure the sonic risks you fear may be harmful.
Our only cautionary note is that the results of your measurements MAY understate the levels of sounds at low and high frequencies. The reason for that is the microphones in most phones of all types are adjusted to be most sensitive to those frequencies included in the range covered by the human voice. Male and female voice frequencies typically range from 200 to 5,000 cycles per second, as shown in the chart at the top of this article.
That means that your smartphone’s SPL meter might very well underestimate the volume of low and high frequency sounds. Some of the iPhone SPL meter apps claim to be “professional” instruments, suggesting that they’ve compensated for that problem by adjusting measured SPL levels by frequency range. But who knows if they’ve done so in accordance with your own phone’s calibration?
We’d still recommend using one of these SPL meter tools, since some information is better than none. But then, “play it by ear.” If the sounds you’re measuring seem to include lots of really low bass frequencies, and/or unusually high frequency levels, increase the measured number that your meter reports by at least +3 decibels. That is the LEAST noticeable difference in sound volumes that the human ear can reliably notice. And you may need to add more, if the bass or high frequency range is obviously dominant.
Once you’ve made your determination of SPLs, you then should remember that sustained exposure to SPLs over 80 decibels can damage your hearing, and that even short exposures to SPLs over 100 decibels can do so as well.