How Do We Measure Volume?

When measuring a sound's volume, you're actually measuring the sound pressure level. This unit of measurement is called decibels.

All sounds we perceive consist of air pressure oscillations that hit our ear drums. Only once they are transferred to our brain, are they converted into information. Depending on the energy with which the oscillations – meaning the sound waves – hit our ear drums, we perceive them as loud or quiet. The more energy a sound has the louder we perceive it. To measure volume we use the unit of decibels – abbreviated to dB.

The lowest perceivable volume, meaning the quietest sound humans can hear, is 0 decibels. Volumes of approximately 50 dB are pleasant for us, while the discomfort threshold starts at around 100 dB. Painful sound levels go from 120 dB on up. What’s important to know is that 100 dB are not twice as loud as 50 dB. Perception of volume is always subjective and depends on one’s own hearing but generally speaking, an increase of 10 dB roughly corresponds to the perceived volume doubling in intensity. Thus, 60 dB are perceived as twice as loud as 50 dB.

Therefore, in noisy environments it is very important to protect one’s hearing to tampen dB levels from a dangerous level to a safe level. Various hearing protection products such as ear plugs for music lovers only filter out disrupting, damaging frequencies, however.

To keep your hearing healthy, educate yourself on hearing protection and what devices are appropriate to where in certain situations.

What is the Decibel Scale?

Table showing the decibel levels of ambient sounds and noises
Measuring sound pressure levels is complex and requires complicated calculations. The decibel scale was introduced to make measurements easier for us to grasp. It looks at the unique capability of human hearing to strongly differentiate low sound levels while even large differences in sound pressure are not as precisely perceived in the high decibel range. Using various filters, particularly low or high frequencies are reduced or regulated depending on our perception. The value on the scale thus corresponds more with our perceptions and  is made measurable. dB values are most often given in dB (A) – the A standing for the use of the A filter, otherwise known as the sound level evaluation curve A.

Decibel values are thus only linear at first glance – 120 dB seem to be twice as loud as 60 dB. That’s not the case, however. The decibel scale is structured logarithmically. For measured values this means that a circular saw is not just twice as loud as talking but that its relative sound pressure is actually approx. 1,000 times as high.

Apart from this so-called dB(A) scale to measure noise, there is the dB(HL) scale used by audiologists and hearing acousticians to determine hearing loss.
Leaves rustling in the wind, or the hum of a computer fan can measure near 10 dB. Whispering reaches 20 dB and normal conversation roughly 60 dB. A passing train or a lawn mower score at 80 dB. Those who love to frequent music concerts are subjected to the same (110 dB) noise level that jackhammers and circular saws produce. The noise created by jet planes – roughly 160 dB – is well into where our pain threshold is. Firecrackers or handguns going off right next to the ear are extremely loud and harmful. They can reach dB values of up to 180. The extent to which we feel sound, meaning how disruptive it is to us, is also influenced by the distance between the source of the sound and our hearing system.

The Impact of Noise on Our Ears

At times, we all put our hands up and cover our ears. It could be a passing ambulance or fire alarm that causes this reaction. Our protective mechanism makes a lot of sense for even a little noise that can cause lasting hearing damage and also adversely affect the entire body. Studies have shown that prolonged exposure to even moderate-elevated levels of ambient noise can have lasting effects:
  • 40 dB and up: Learning and concentration become challenging
  • 60 dB and up: Long-term exposure may result in hearing damage
  • 65 dB and up: Higher risk of cardiovascular diseases in case of long-term exposure
  • 85 dB and up: Loud work places can do permanent damage over the years
  • 120 dB and up: Hearing damage possible even in case of short-term exposure

Who is at Risk for Hearing Damage?

In particular, people subjected to certain noise levels as part of their jobs, are at risk of suffering hearing loss sooner than later. Permanent noise from power drills, chainsaws, air planes or music is present in many occupations.
Forestry workers, road construction workers, builders and factory workers are just as much at risk as professional musicians in orchestras or bartenders that work in noisy nightclubs.

Tips for Your Hearing Protection

Protect your hearing from prolonged and excessive noise:
  • Turn the volume to the minimum setting when listening to music using headphones
  • Maintain as much distance as possible to the source of the noise
  • Put your hands over your ears when perceiving a sound as disruptive
  • Wear ear plugs when subjected to high sound pressure for prolonged periods of time – for instance at concerts or on a construction site
  • Regularly take hearing tests to detect possible hearing loss at an early stage and to allow treatment