What are decibels, and how are they measured? Decibel scale, measurement units & sound intensity
The human ear is an incredibly flexible hearing device. It has a smart built-in mechanism that reduces its own sensitivity as the sound level goes up and it also has the extraordinary ability to handle a vast range of sound power levels. It can hear the sound of a coin dropping close-by as well as the booming of a jet engine miles away.
Decibels
In A Hurry?
If require the Best Hearing Protection for this item, and do not want to read the entire article, below are my recommended ear protection.
Last update on 2021-07-27 / Affiliate links / Images from Amazon Product Advertising API
Which are the best Earplugs for Measuring Decibels?
For Measuring Decibels, the best ear plugs are REED Instruments R8060 Sound Level Meter with Bargraph.
However, this will depend on several things. If you use them a lot, for example, if it is your principal job, or perhaps just minor use. Also, if you want to use these ear plugs for other things
There are earplug options available, for example: Convenient Fitting, Noise Reduction Rating (NRR), Long-Lasting, Flexibility. As you can see, there is a lot in picking the best fit.
What is a decibel?
The decibel (symbol: dB) is a relative unit of measurement equivalent to one-tenth of a bel (B). It is used to exhibit the ratio of one value of a power or root-power quantity to another on a logarithmic scale. A logarithmic quantity in decibels is called a level. Two signals whose levels vary by one decibel have a power ratio of 101/10. Zero decibels (0 dB) is the lowest sound audible to a healthy human ear. From there, every increment of 3 dB means doubling of sound power or acoustic intensity.
Decibel’s definition originates from the readings of power in telephony of the beginning of the 20th century in the Bell System in the United States of America. One decibel is one-tenth (deci-) of one bel, named as a tribute to Alexander Graham Bell; however, the bel is rarely used. Today, the decibel is used for a wide spectrum of measurements in science and engineering, particularly in acoustics, electronics, and control theory. In electronics, the gains of amplifiers, attenuation of signals, and signal-to-noise ratios are usually measured in decibels.
Sound power and loudness
The relative loudness that we perceive isn’t something that can be objectively measured; it depends on the individual. Most of us identify a particular sound to be two times as loud as another one when they are about 10 dB apart; for example, you will find a 60-dB air conditioner twice as loud as a 50-dB refrigerator. Yet that 10-dB variation is actually a ten times increase in intensity. A 70-dB dishwasher will sound approximately four times as loud as the 50-dB refrigerator, when it comes to acoustic intensity, the sound it makes is 100 times as strong.
Here's another example: If the sound from one typewriter registers 60 dB, then ten typewriters clicking would register 70 dB (not 600 dB!), and they would sound only two times as loud as one machine. You would need 100 typewriters to attain a noise level of 80 dB, and together they would sound only four times as loud as a single typewriter.
The possibility for a sound to damage hearing is proportional to its intensity, not its loudness. That's why it's delusive to rely on our subjective perception of loudness as a sign of the risk to our hearing.
Noises For A Decibel Meter
The following infographic shows a list of the various noises when you are out and about. Any noise over 70-80db over a long period of time may cause damage to your hearing. A noise of over 120dB may cuase immediate harm to your ears
Here are some linear and non-linear sound levels in our circumambience :
Decibels | Intensity (In watts per sq/m) | Type of sound |
0 | 10−12 | Dead silence |
10 | 10−11 | Soundproof room |
20 | 10−10 | Studio |
30 | 10−9 | Lecture room |
40 | 10−8 | Quiet room in a home |
50 | 10−7 | Restaurant/private office |
60 | 10−6 | Engaging in a conversation/ work office |
70 | 10−5 | Telephone bell/street noise |
80 | 10−4 | The noise inside of a car |
90 | 10−3 | The noise inside of a bus/truck |
100 | 10−2 | Electric saw |
110 | 10−1 | Orchestral music |
120 | 1 | Loud rock concert |
130 | 10 | Artillery fire (pain threshold) |
Phons and Sones
The phon is a non-regular noise unit that is intended to reflect perceived loudness, and is based on psychoacoustic tests in which volunteers were asked to adjust the decibel level of a baseline tone of 1 kHz until it was the equal loudness as the signal being measured. So for instance, if a sound is 70 phons, that means it sounds as loud as a 70-dB, 1-kHz tone. The dBA scale is now largely used rather than phons. The sone is a more intuitive measure of loudness, because a doubling in the number of sones equals a doubling in loudness that you perceive(unlike the logarithmic phon scale). Noise levels of household fans are usually measured in sones.A-weighting dB(A) and C-weighting dB(C)
Measuring noise levels relating to loud noise at work are usually given in dB(A) or dB(C) - those frequency weightings are applied to the decibel measurements (A and C frequency weightings), actually they are decibel scale readings that try to replicate the sensitivity of the human ear to various sound frequencies.- A-weighting (A-frequency-weighting): ‘A’ Weighting is predominantly used and covers the full frequency range of 20Hz all the way up to 20 kHz. The human ear is most sensitive to sound frequencies between 500 Hz and 6 kHz while at lower and higher frequencies the human ear is not that sensitive. The 'A' weighting adjusts the sound pressure readings to display the sensitivity of the human ear and is therefore mandatory all over the world for hearing damage risk readings.
- C-weighting (C-frequency-weighting): The C-weighting is mainly focused at the effect of low-frequency sounds on the human ear.m Compared with the A-weighting it is essentially flat or linear between 31.5Hz and 8kHz, the two – 3dB or ‘half power’ points. Peak Sound Pressure Measurements are made using the C- frequency weighting. Measurements are primarily displayed as dB(C) or dBC. Or for example as LCeq, LCPeak, LCE – where the C shows the C-weighting.
Sound Level Measuring
A sound level meter is the device usually used to measure noise levels on the decibel scale. Several factors affect the noise level reading:- The gap between the meter and the source of the sound
- The direction the noise source is facing, relative to the meter
- Noise dissipation and reverberation
Final words
We hope that we managed to clarify some of the terms that you’ve been confused about or unfamiliar with.The Decibel scale is one of the most important accomplishments when it comes to sound science, and will undoubtedly be in use for decades to come.
- Large Screen LCD Display
- The sound level meter is an instrument used to measure the ambient sound level,such as sound level around factories,workshops,schools,residential,offices,road,audio etc
- It also can be appropriate for noise engineering,product quality control,health prevention and treatment,etc.This audio noise measure device is a great tool for checking, monitoring or controlling and test the sound level of any environments. It is widely applicable for personal, families, business, studies, industrial and etc
- With the measuring scope from 30 to 130dB and shifting function. Digital display,good anti-interference performance,power saving
- With the backlight feature,it is appropriate for gathering the sound data at night.Backlight auto power off function is provided.With power saving and high-reliability circuit design,well-design high-efficiency power supply circuit makes the batteries more durable
- Composite material injection molding process is adopted for casing with anti-drop structure design.It is not only extremely wear-resisting,but also elegant,It’s a mini handheld portable sound level reader
- High accuracy of ±1.4 dB meets Type 2 standards
- Triple range measurement (60dB dynamic range)
- Digital analog bargraph
- Data hold and Min/Max hold
- Includes windshield ball, hard carrying case and battery
Last update on 2021-07-27 / Affiliate links / Images from Amazon Product Advertising API
References
If you require more information, please check these references
The Journal of the Acoustical Society of America , article, "asa.scitation.org", retrieved on, Tue 01-December-2020
https://psycnet.apa.org/record/1936-05651-001 , article, "psycnet.apa.org", retrieved on, Tue 01-December-2020
On the Validity of the Loudness Scale , article, "asa.scitation.org", retrieved on, Tue 01-December-2020
