Noise Reduction Calculator — Formula
## Combining Sound Levels
Sound levels in decibels are logarithmic, so they cannot simply be added.
### Formula
**L_total = 10 log10(10^(L1/10) + 10^(L2/10))**
This converts each level to linear power, sums them, and converts back. Two equal sources produce a combined level 3 dB higher than either alone (not double). A noise barrier reduces the combined level by its insertion loss.
Sound levels in decibels are logarithmic, so they cannot simply be added.
### Formula
**L_total = 10 log10(10^(L1/10) + 10^(L2/10))**
This converts each level to linear power, sums them, and converts back. Two equal sources produce a combined level 3 dB higher than either alone (not double). A noise barrier reduces the combined level by its insertion loss.
Esempio Risolto
Two machines at 85 dB and 82 dB with a 10 dB barrier.
- 10^(85/10) = 316,227,766
- 10^(82/10) = 158,489,319
- Sum = 474,717,085
- L_total = 10 x log10(474,717,085) = 86.7 dB
- After 10 dB barrier: 86.7 - 10 = 76.7 dB