What is Loudness of Sound? What Factors Does It Depend On?

Loudness of sound refers to how strong or intense a sound appears to our ears. It is the human perception of sound energy and depends mainly on the amplitude of the sound wave, the greater the amplitude, the louder the sound. 

Loudness is measured in decibels (dB), a unit that expresses the ratio of sound intensity compared to a reference level. A whisper is around 30 dB, normal conversation around 60 dB, and jet engines about 120 dB, which can be harmful to hearing.

Loudness depends on several factors:

1. Amplitude of vibration – higher amplitude means louder sound.
2. Distance from the source – loudness decreases as distance increases.
3. Surface area and medium – sound travels differently through air, water, or solids.
4. Sensitivity of the ear – human ears hear frequencies between 20 Hz to 20,000 Hz better in mid-range tones.
5. Duration of exposure – longer exposure increases perceived loudness.

Loudness is subjective because different people hear the same sound differently. Engineers design soundproof materials and acoustic systems by studying these factors. Understanding loudness helps in preventing noise pollution and protecting hearing health.