The Loudest Sounds in the World

Human beings have a natural weakness in that we have a hard time conceptualizing things that exist outside of our normal scale of reference. While our bodies can certainly tell the difference between minute differences in temperature and size, beyond a certain point our brains just can’t properly handle certain magnitudes. While it’s fairly easy to imagine what it means to walk a kilometer or a mile, when confronted with something the size of tens of thousands of kilometers, our brains have a hard time processing what that size actually means. 

Sound is a bit unique in this sense, due to the way that we define what sound is. Although some elements of sound, such as pressure or energy, can extend beyond normal human scale in natural phenomena, the precise application of these ideas in what we would usually refer to as sound only really works well at our human scale. To see what this means, let’s have a look at the decibel scale, and look at some of the loudest noises. 

Average house noise scale

Estimating the loudest noise in the average home is both complicated and moot. Environmental noise, technological levels, and noise levels of devices from different manufacturers can all vary greatly, making it difficult to estimate what the loudest individual noise would be.

So instead we’ll take a moment to discuss a couple of key ideas of the decibel scale, and draw some parallels to common household objects, to establish a good baseline going forward. 

So what is a decibel? In scientific terms, it’s a relative intensity unit of measurement whose measurement lies on a logarithmic scale. In more layman’s terms, there are two important properties of a decibel:

• Physically speaking, a decibel is a measure of the intensity of a sound wave. The louder a sound is, the more intense the wave it produces, and the higher it is on the decibel scale.
• Decibels are a logarithmic scale, meaning that the intensity doesn’t increase linearly per decibel. So an increase of 3 decibels is actually a doubling of intensity, and an increase of 10 decibels is a tenfold increase in intensity. 

This may seem abstract, but applying decibel values to commonplace items should help make the scale seem a bit more concrete. 

The scale starts at 0 decibels, as one may expect, but it’s almost impossible to actually hear 0 decibels ordinarily.

• The sound of breathing clocks in at 10 decibels
• Whispering produces around 15 decibels
• The environmental noise of a quiet rural area sits at 30

From around 10 decibels to around 70 decibels is the scale at which sounds are generally comfortable for human hearing, which is where sounds like normal conversation (60 decibels), suburban environmental noise (50 decibels), air conditioners (60 decibels) and most bird calls (44 decibels) fall. Ideally, most sounds with a normal household would stay within this range, although this isn’t necessarily the case. 

Past the high 70s, sounds start to become hurtful to human ears.

• Most vacuums that aren’t made to be quiet fall somewhere between 70 and 85 decibels, as does the average environmental noise from an urban environment.
• Most passenger cars fall at around 75 decibels, and a freeway can reach up to 85 decibels.
• Toilets also exist in this 75-85 range.
• A noisy restaurant can be as high as 90 decibels.

Although this range might not necessarily hurt, prolonged exposure to sounds over 85 decibels can cause permanent damage. As such, this should hopefully be the high end of noise experienced in the average home. 

Once sounds start to reach the 100s, it starts to become physically painful, with noises over 140 causing almost immediate pain. Things like garbage trucks, heavy industrial machines, and jet take-offs from a fair distance away clocks in at 110 decibels. 110 decibels is also the high-end of a baby’s cry, although they rarely stay this loud for very long. Music concerts, thunderclaps, and chainsaws all measure in at around 120 decibels, about 32 times louder than a 70 decibel sound is. Jet take-offs at close range usually measure around 140 decibels, just short of the 150 decibel mark that is usually associated with eardrum rupture. Any noise beyond this point would be dangerous to the human ear. 

The loudest noise in the animal kingdom

Of course, all the noises we’ve discussed so far have been man-made objects, but what about animal noises? Where do they fit on this scale?

For starters, most noises from household pets like cats and dogs fit well into that comfortable range for human ears. Most cat noises sit around 45 decibels, 85 at the highest, and dog barks rarely go above 90 decibels. The 90-120 decibel range includes most animals commonly thought of as loud, such as wolf howls (90 decibels), lion roars (114 decibels), and cicada buzzes (120 decibels). Since most animals have pretty similar limits to what humans have for sound intensity, most animals don’t go above this range. 

The loudest animal sound is a bit of a trick question, as there are technically two different answers depending on how you want to define the question. The loudest intentional sound in the animal kingdom is the calls of a whale, clocking in at over 180 decibels, according to most sources. Considering that whales generally need to communicate over the massive distances of the ocean, this incredible amount of noise makes sense.

There is one animal that can technically create a noise louder though; the pistol shrimp. Yes, you’ve read that right, a shrimp! Known for having a locking claw that can kick out with incredible force, the pistol shrimp can hit prey with enough energy to heat the water around it, and create sounds that top out at around 200 decibels. So although the sound isn’t the primary goal of the pistol shrimp, this is generally considered the loudest sound in the animal kingdom. 

Loudest noises on earth

So far we’ve mostly looked at noises that fit within the range of regular existence, things that people generally interact with regularly. But there are some events that are so energetic that they can create noise on an entirely different level. 

Part of the difficulty of measuring this high end is the fact that it’s generally ill-advised to be near any event that can cause a sound over 200 decibels. The launch of the Saturn V rocket, for example, is commonly cited as reaching 180 decibels from a long distance away, but most estimates place it as being close to 230 decibels up close. Actual measurements of how loud a rocket launch is are obviously dangerous, for obvious reasons, but even based on these estimates, rocket launches can be awe-inspiringly loud. 

Explosions are in a similar situation, where proper measurement is made dangerous by the inherent risk involved, although in the case of nuclear weapons proper data is also obfuscated by the fact that public data on nuclear testing generally isn’t widely available. Anecdotal evidence can be helpful in analyzing how loud a nuclear blast is. Reports of the blast at Hiroshima indicate that the noise was comparable to a lightning strike for those several miles away, putting it on a similar scale as a rocket launch. But direct data is hard to come by in these cases, so the actual noise levels could be higher or lower than these estimates. 

Thankfully there is one event that puts even nuclear explosions out of the water when it comes to noise scale. The eruption of a volcano on the island of Krakatoa in 1883 is widely considered to be the loudest sound in recorded human history, an event that shattered the island itself and sent a shockwave that was felt around the world. Measurements of the eruption from over 100 miles away reach up to 170 decibels, approximately on par with a nuclear explosion only one mile away. Estimates of how loud it was at the source reach up to 300 decibels, over 1000 times louder than most estimates for a nuclear explosion.

The eruption was so massive that weather stations worldwide had errors in pressure readings for days afterwards, due to the shockwave Krakatoa created. Although each of these cases are still largely working through estimates and secondhand accounts, due to how far above the other candidates Krakatoa is, it’s fairly safe to say that it is the largest sound recorded on earth. 

The loudest sound in the known universe

So the exciting next question is obviously what the loudest sound in the universe must be, if earth alone is already reaching such heights. The unfortunate answer is that outside of earth, the definition of sound starts to get a little bit tenuous at best. Although the decibel system is a measure of general wave intensity, not necessarily just through air, most scientists would still say that some medium is required for a wave to go through before it can be considered a sound. What this means is that although things like solar flares, planetary collisions, and other celestial events would certainly have energy on a scale beyond what we have on earth, there isn’t really a medium for them to pass through, so calling them noises would be a bit misleading. 

Not all hope is lost though, as there are a few special cases. Supernovas, for example, usually happen amidst the remains of a star, so the argument could be made that a sound is passing through the dust particles. Estimates of how loud a supernova can be range from the high 300s to the mid 400s in decibels, depending on the mass of the star in question.

Although not on the same scale, some astronomers also posit that celestial events in spaces such as the Perseus galaxy cluster would happen amid enough hot gas to be conventionally considered a sound, although again actual decibel estimates of these events would require several layers of estimation. 

Like with the Krakatoa case, there is one particular event that defines the high end of universal loud noises, and that is the collision of black holes. Due to the scale of the mass involved in two black holes colliding, such a merger would create waves in actual spacetime, an event which fairly recently allowed scientists to actually measure gravitational waves during the LIGO experiment. These gravitational waves have an associated intensity that could be applied to the decibel scale in a very similar way to sound waves. Although this intensity pushes the boundary of what can be considered a “sound”, the common estimates of upwards of 500 decibels makes a compelling case for them being the loudest event in the universe. 

Conclusion

Beyond black hole mergers, there are of course more and more energetic events that could conceivably be redefined to fit onto the decibel scale. From the big bang that started the universe to energy-spewing quasars, the universe is filled with sounds that are to black hole mergers what they themselves are to Krakatoa.

But, in truth, beyond around 200 decibels the definition of sound as applied by the decibel system becomes less about acoustics, and more and more about pressure, which doesn’t apply particularly well to conventional ideas of sound.

So although the universe is full of incredibly powerful and energetic events that boggle the human mind, you can still rest content in the fact that our normal scale for noises is plenty loud enough.