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How Loud is Too Loud? (Hearing Extremes!)

VO: Eric Cohen WRITTEN BY: Nathan Sharp
Lots of us have felt that ringing in our ears after a rowdy rock concert... But how much more sound can our ears realistically withstand? We're doubling up on decibels today, to explore the extremes of audiology and loudness. So, turn those speakers up - to a safe level, of course - and enjoy!
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How Loud Is Too Loud?

As we’re sure you’ve heard from numerous lectures and safety guidelines, the human ear can only withstand so much sound before it breaks. Those innocuous things on the side of your head are pretty sensitive. Hearing issues like deafness and tinnitus are perhaps surprisingly common problems for people all around the world. One study published in 2011 found that as many as 48 million Americans, or 20% of the entire population, suffers from some form of hearing issue. However, many people are actually oblivious to the hearing problems they have, have learnt to ignore them, or purposefully neglect to see a specialist because they don’t want to wear hearing aids.

Some hearing issues are biological, but they can also be self-made and avoidable. Things like working in a loud environment without ear protection, attending one too many rock concerts, or even simply listening to music through headphones on too high a volume can cause irreversible harm. But what are the extremes? And how loud is too loud? What’s the line between acceptable, natural and practical sound levels and unnatural, deafening, damaging noise?

First, you gotta know your decibels. As the unit of measurement used to determine the loudness of a given action or object, decibels are a record of the pressure from any particular sound wave. There’s some heavy science behind these things, but what’s important for today’s question is that higher decibel readings equate to greater sound pressure. In other words, the higher the decibel number, the louder – and potentially more destructive – the sound is. For example, a watch ticking at 20 decibels is louder than leaves rustling at 10. A conversation at 40 decibels is much louder than the watch ticking at 20, and so on.

But while the science behind sound readings is objective, loudness is a subjective, relative experience. For example, a jackhammer drill sounds awfully different – and is much more dangerous – if you’re the one operating it, compared to someone walking past the construction site, on the other side of the road. Another important factor is the length of time that you’re exposed to the noise in question. Using the jackhammer for only five minutes could hurt your unprotected ears, but it would still be preferable to using it for six hours straight. Animals also interpret noise much differently than we do. For example, dog whistles are inaudible to humans but painful for dogs. This is because dogs, like many other mammals, can detect much higher frequencies.

All of that said, there are clear and definite limitations for what the human ear can endure.

Humans have made dramatic technological growth over the past few thousand years. Living in the wild as hunter-gatherers way back when, our ancient ancestors would’ve experienced a much quieter day-to-day life. Even 100 years ago, the background noise would’ve been nothing compared to the crashes, clangs, screams, sirens and engines in a contemporary city, town or even moderately built-up area. Luckily for us, the human ear can handle the general hubbub of the modern world – with average background noise in a city registering at around 80 decibels. And while that is considered “very loud” by the experts, it is relatively manageable. Other everyday things that fall under that ‘very loud but manageable’ umbrella include most dishwashers, vacuum cleaners, and alarm clocks.

However, 80 is cutting it very close. Audiologists and hearing specialists generally agree that 85 decibels is the acceptable threshold for noise – anything louder than that may result in permanent hearing damage. So, most lawnmowers only just make the cut. But again, the length of sound exposure is key, with louder noises requiring lower exposure times – if you want to preserve your hearing. In fact, loud noises are a law and order matter. The Ontario Ministry of Labour states that the maximum exposure time for a noise level of 85 decibels is eight hours. Similarly, US legislation says that workers shouldn’t experience 90 decibels for any more than eight hours at a time. So, legally speaking, we might say that anything over 90 is ‘too loud’. But biologically speaking, we can handle more.

Push the decibels up to 100 for a chainsaw or an especially lively nightclub. At 110 you start hitting rock concert levels of noise, especially if you’re stood by the speakers. And right about now your recommended exposure time plummets to just one and a half minutes. So, going by officially accepted figures, even one two-hour concert could wreak havoc on your hearing. General warning signs of dangerous noise levels include the inability to hear someone standing two feet away from you, yelling to be heard, and muffled sounds long after leaving the noisy area. If you’ve ever been to a rock gig, you’ll likely recognise all of those.

But of course, there are louder things on this Earth than simply watching your favourite band – and you’d still be unlucky to pick up a lasting problem while listening to live music. Our jackhammer from earlier stands at 130 decibels, while some guns can soar over 140 when fired (which makes you wonder why weapon-wielding movie characters never seem startled by the noise). And then there are the real big hitters, like jet engines on take-off and bomb explosions, which can hit 150 decibels and more. Once you reach this level of noise, all hope for your ears is lost. If you’re directly exposed to them, without adequate protection, your eardrums will rupture and permanent deafness will probably set in.

We have gone higher, though. One of the loudest sounds that human beings have ever experienced was the eruption of the Indonesian volcano Krakatoa, in 1883. With estimates placing the explosion at around 180 decibels even up to 100 miles away, it was loud enough to blow out the eardrums of anyone nearby, and was distinctly heard at up to a 3,000 mile radius. But what about those unfortunate enough to be at (or within just a few miles of) the actual explosion. At upwards of 180 decibels, you’d certainly go deaf instantly, and then you’d struggle for breath from the sheer force of the sonic pressure, and the sound might even kill you outright.

Scientists have speculated that a noise level of 195 decibels would likely result in literal human death. And not a nice one, either. At this inconceivable level, the air pressure would be great enough to burst your major organs and create fatal air bubbles in your blood. Forget the human ear, a sound such as this would be catastrophic for the entire human body.

So, what then? What’s louder than something so loud it’ll actually cause you to explode? Well, sound can even get loud enough to set stuff on fire. According to estimates, NASA’s Saturn Five rocket reached an incredible 220 decibels on launch. This is incomprehensibly loud. The sound waves doubled up as shock waves, and reportedly ignited some nearby grasslands. Further still, it has been speculated that the sound of Saturn Five actually melted concrete. And if concrete can’t survive, we can only assume that our own bodies would pretty much vaporize into nonexistence. In fact, at those levels the sound would struggle to survive itself, becoming noticeably distorted.

So, how loud is too loud? Anything that’s 85 decibels if you’re going by governmental guidance; a rock concert if you’re an avid but anxious music fan; or a 150-decibel noise, if burst eardrums are your personal cut-off point. The Saturn five rocket or Krakatoa, however, go beyond everything else. These immeasurable sounds are (and possibly were) loud enough to kill people, and disintegrate the surrounding area. Now, that really is pretty loud.
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