Music & Acoustics

Intermediate

Sound Intensity Level (dB)

Sound intensity expressed in decibels relative to the hearing threshold.

Formula

L = 10 \log_{10}\!\left(\frac{I}{I_0}\right)

Variables

LLevel (dB)

IIntensity (W/m²)

I_0Reference 10⁻¹² W/m²

Example

I = 10⁻⁶ W/m²: L = 10 log(10⁶) = 60 dB

Did You Know?

Because it is logarithmic, a 10 dB rise sounds roughly twice as loud but carries ten times the power.

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