声强计算器 — 公式
## 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.
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.
计算示例
A speaker emitting 0.01 W of sound power, measured at 1 m (sphere area = 4*pi*1² = 12.566 m²).
- I = P / A
- I = 0.01 / 12.566
- I = 7.958 x 10^-4 W/m²
- L = 10 * log10(7.958e-4 / 1e-12)
- L = 10 * log10(7.958e8)
- L = 89.0 dB