Sound is everywhere.
When associated with birds, wind caressing the leaves of a tree or our favorite piece of music, it is beautiful sound. When associated with a plane taking off, the lawnmower of your neighbor or the jackhammer of a construction site, sound becomes noise.
Sound is measured in decibel unit or one tenth of a bel and is written as "db".
It can be used to a change in value (+/- 1dB) or an absolute value (-20dB).
The Bel unit was created with the telephony industry to measure telephony power through the line, in recognition of Alexander Graham Bell.
The Bel unit is no longer used, and the decibel is today’s reference in sound measurement.
Simply said, decibel measures the volume of sound.
It is also used when measuring SPL (Sound Pressure Level) and expresses the relative intensity of a sound on a scale from 0 for the least perceptible sound to about 130 dB for pain level.
Scientists in the medical field have established different charts acknowledging that sounds up to 80db is acceptable for a healthy earring while sounds above 80db could be detrimental to our earring acuity when played over a long time.
We all have been to rock concerts with a level of decibels way higher than the recommended amount. At times, you may hear a persistent whistle due to overpowering volume.
When listening to music at home or a movie with home theater system, we often raise the volume to hear all the details of the music, dialog and sound effects embedded within a very dynamic soundtrack, but we all need to pay extra attention about listening to loud sounds over a long period of time, as this is how we adversely affect our hearing. Needless to say, the same goes for playing music, whether amplified or not.