Sound pressure level is measured in decibels (dB), which is a logarithmic scale, meaning the sound pressure decreases significantly with a small increase in distance. This formula is based on the inverse square law, which states that the intensity of a sound wave decreases proportionally to the square of the distance from the source. This formula assumes a free field environment with no obstacles or reflections, which might not always be the case.
| Variable | Unit |
|---|---|
| SPL1 | dB |
| d1 | meters |
| d2 | meters |