Calculateur d'Intensité Sonore — Formule

Sound Intensity

Sound intensity is the power carried by a sound wave per unit area perpendicular to the propagation direction.

Formula

I = P / A

For a point source radiating uniformly, A = 4*pi*r². The intensity level in decibels is L = 10 * log10(I / I_0) where I_0 = 10^-12 W/m² is the threshold of hearing.

Exemple Résolu

A speaker emitting 0.01 W of sound power, measured at 1 m (sphere area = 4*pi*1² = 12.566 m²).

  1. I = P / A
  2. I = 0.01 / 12.566
  3. I = 7.958 x 10^-4 W/m²
  4. L = 10 * log10(7.958e-4 / 1e-12)
  5. L = 10 * log10(7.958e8)
  6. L = 89.0 dB