Sound is all around us, whether we notice it or not. Humans never experience total silence; in fact the only place where true silence can exist is in a vacuum. Our organs, the blood rushing through our veins and even our ears are constantly producing noise.
While sound is a constant throughout our lives, the intensity of sound can have a profound effect on our hearing. Sounds that are too loud can damage our ability to hear, and extremely intense noises of 185-200 decibels can rupture human organs and even cause death!
Rock concerts, automobiles, household appliances: in modern society, exposure to loud noises is inevitable, but how do we know when a sound is too loud?
What is a decibel and how can I tell how loud something is?
A decibel (dB) is a measurement used to gauge the intensity or ‘loudness’ of a sound. A decibel rating of 0 represents near silence, the softest sound detectable by the human ear, while human breathing is about 10 dB, a whisper is 15 dB and a normal conversation measures in at around 60 dB.
The scale dips into negative numbers, which are too quiet for humans to hear. The quietest place recorded on Earth is a specially engineered room by Microsoft, which measures at -20 dB; people aren’t allowed in the room unsupervised for more than 15 minutes at a time, as it’s thought that any longer and the silence could drive a human insane!
The decibel scale works logarithmically, so that a measurement of 10 dB is 10 times more intense than a measurement of 0 dB, while a 20 dB sound is 100 times stronger than a sound of 10 dB.
Hearing damage is related to both noise intensity and the length of exposure. Sounds louder than 85 dB are enough to cause hearing loss after about 8 hours of exposure, while sounds over 140 dB cause instant damage and can result in immediate hearing loss, not to mention pain.
So how loud is too loud? Check out this list of sounds, including their decibel measurements and maximum exposure time before hearing damage occurs:
|Decibel Level||Examples||Hearing Damage|
|70 dB or under||Alarm clock, busy traffic, busy restaurant, television||No permanent damage|
|85 dB||Bulldozer idling, blow dryer, vacuum cleaner, kitchen blender||After 8 hours of exposure|
|90 dB||Subway train, passing motorcycle, people shouting||After 2-4 hours of exposure|
|100 dB||Electric drill, factory machinery, jack hammer, nightclub, loud MP3 player||After 15 minutes of exposure|
|120 dB||Siren, rock concert, loud symphony, sports arena||After 10 seconds of exposure|
|140 dB or over||Firecrackers, firearm, plane taking off||Immediate damage and pain|
How loud noises can affect your hearing
Humans process noise when a sound wave vibration enters the ear and vibrates tiny hair cells called stereocilia, which can be found inside the cochlea. The stereocilia convert the vibrations into electrical information, which is then sent to the brain. Vibrations that are too powerful damage these hair cells so that they no longer function.
Damage to stereocilia is often gradual with no pain or immediate change in perception; unless you are exposed to sudden powerful damage, the decline in hearing can be so gradual that it takes years to notice. Sounds which measure 150 dB or higher are considered loud enough to rupture your eardrum, which causes damage to the inner hear and hearing loss.
Signs that a sound is too loud
An easy way to tell is a noise is too loud is if you need to raise your voice to be heard above it. Have you ever been listening to music with headphones and found that you start speaking to people in a raised voice? Or have you ever had to shout to hold a conversation in a restaurant or bar? These are sure signs that you are being exposed to sound at or above 85 dB and could be at risk of hearing damage.
Exposure to powerful sounds can also damage the stereocilia in such a way that they continue to mistakenly send signals to the brain after the sound has stopped, resulting in ringing ears or ‘tinnitus.’ A ringing in the ears is a clear indication of hearing damage and a sign that you need to immediately limit your exposure to the cause.
Ringing in the ears is usually temporary, although repeated exposure can lead to chronic tinnitus. If your hearing seems dulled or muffled, it’s also a sign that damage has occurred.
Tips to reduce hearing loss from loud noises
A few easy changes can reduce your risk of hearing loss from loud noises:
- Turn down the volume on your music. To reduce the decibel level of your MP3 player, try to keep the volume to 60% or less of the maximum possible volume. Some phones and MP3 players come with a smart volume feature which allows you to set a maximum volume of your choice, or restrict the volume to a safe level.
- Use noise-cancelling headphones. Studies have shown an increased rate of hearing loss in teenagers due to the common practice of listening to loud music on MP3 players using earbuds. In order to block out surrounding noises, people turn the volume up even further than normal. Invest in some noise-cancelling headphones that block outside noises, making it less necessary for you to turn the volume way up.
- Use ear plugs or earmuffs. Wear hearing protection when you’re at a rock concert, while working in a loud environment such as a factory or construction site, or at any other noisy venue. Available options range from cheap foam inserts, to specially molded plugs to fit your individual ears.
- Take breaks. Reduce the exposure time to loud noises, especially those of between 85 to 120 dB.
- Move away from the sound. Decibels are measured close-up to sounds, but the more distance you put between yourself and the source of the noise, the less intense those sound waves will be once they reach your ears.
Ultimately, the best way to decide whether a sound is too loud is to use your own judgment. If a noise volume is irritating, unpleasant or too loud to hold a conversation, then it’s too loud and will eventually cause hearing damage.