平方反比定律

输入下面的值，然后按下“计算”键来确定到信号源的新距离的声压级。

  • UOM（英尺、码、米等）
  • dB SPL
  • UOM（英尺、码、米等）

Results

新距离上的 dB

Sound pressure level - SPL decreases 6.02 dB as a listener's distance doubles from the sound source. This number is commonly rounded down to 6 dB. The opposite is true as the listener halves the distance to the source, so that the SPL decreases or increases by 6 dB with every distance doubling or halving, respectively. The Inverse Square Law is used to calculate the change in SPL with distance, and is useful in predicting the sound pressure level a listener will experience as speaker placement and sound levels are considered.

Sound pressure level showning inverse square law
  • LN = LR - 20 log (DN/DR)
  • DR = reference distance
  • DN = new distance
  • LR = SPL at reference distance
  • LN = SPL at new distance

FAQs

The inverse square law calculator shows how sound level decreases as distance from the source increases.

It helps estimate SPL loss over distance during system planning.

It assumes free‑field conditions without reflections.

It is often used alongside amplifier power and speaker calculators.