Decibels (dB) and frequency are terms used to describe the sound levels and the number of cycles of a sound wave in a second.
To get a clear idea of the technical words that describe the facts about hearing impairment and noise, we have compiled the basic data on dB and frequency.
Frequency
The frequency of a sound is the number of cycles of a sound wave in a second. The unit of measurement is hertz (Hz). The frequency of a sound increases as the number of cycles per second increases. Vibrations between 20 and 20,000 cycles per second are interpreted as the sound a healthy person hears. A high pitched sound could be a piccolo or the song of a bird. The bass sounds could be the sound of distant thunder or the tones of a bass.
Decibel (dB)
The term dB (decibel) and the dB scale are used worldwide to measure sound levels. The decibel scale is a logarithmic scale in which twice the sound pressure corresponds to an increase in the level of 6 dB.
It is very important to understand that the term ‘dB’ can have different meanings and that it is not a fixed value such as volt or meter, etc. The value of a dB depends on the context in which it is used.
Below you will find examples of different sound intensities expressed in dB (HL):
180 dB: Rocket on takeoff
140 dB: Engine of a jet plane when taking off
120 dB: Rock band
110 dB: Strong thunder
90 dB: Traffic in the city
80 dB: The radio at a high volume
60 dB: Normal conversation
30 dB: Soft whisper
0 dB: The lowest sound that a person perceives
What are decibels?
They are a unit of measurement that allows to establish the power of the noise.
The hearing threshold is 0 decibels and the pain threshold is approximately 120.
The noise level is measured in decibels (dB), a sound unit equivalent to one tenth of the Bell, a measure of sound power that expresses the difference between two sounds whose intensities are in a ratio of 10 to 1.
The decibel is a mathematical relationship of the logarithmic type where if a noise increases 3 dB, it means that the perceived sound energy is doubled.
The hearing threshold is at 0 dB, and the pain threshold is around 120 dB. However, the ear does not respond equally to all frequencies of a noise, that is, we hear certain sounds better than others depending on their frequency.
For this reason the decibel A (dBA) was defined, a unit of sound level measured with a previous filter that removes part of the low and very high frequencies. Thus, before the measurement, only the most harmful sounds for the ear are preserved, which is why the exposure measured in dBA is a good indicator of auditory risk.
The weakest sound that a healthy ear can hear or detect has an amplitude of a twentieth millionth of a Pascal, something like 5,000,000,000 times less than normal atmospheric pressure. It is considered that no more than 30 decibels should be registered so that a person can sleep well, while 120 decibels constitute the threshold of the bearable
