What is a decibel (dBspl)? (A) A type of signal distortion (B) A mathematical constant (C) A measure of sound intensity (D) A unit of frequency
Answer (1)
The correct answer is (C) A measure of sound intensity.
A decibel (dB) is a unit used to measure the intensity or loudness of sound. Specifically, dB SPL (Sound Pressure Level) is a measure of sound intensity at a given location, and it's expressed in decibels. The term 'decibel' combines 'deci,' meaning one-tenth, and 'bel,' named after Alexander Graham Bell, the inventor of the telephone.
Sound intensity is a critical concept because it relates to how we perceive sound in our daily lives. The human ear can detect a wide range of sound intensities, from the faintest rustle of leaves to the roar of a jet engine. Measuring sound intensity in decibels allows us to quantify these differences in a manageable range.
The formula to calculate decibels in sound pressure level is:
L p = 20 × lo g 10 ( P ref P )
Where:
L p is the sound pressure level in decibels.
P is the sound pressure of the sound wave.
P ref is the reference sound pressure, typically set at 20 μ Pa , which is the quietest sound a human ear can typically hear.
In summary, decibels are a logarithmic unit used to convey the intensity of sound relative to this reference level, allowing for a precise comparison of different sound levels and understanding the intensity of the sound that humans experience on a day-to-day basis.
