Soma geral SPL (2 fontes)
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
About this calculator
The total SPL sum calculator determines the combined sound pressure level (SPL) from two distinct sound sources. It uses the formula SPL = 10·log(10^(L1/10) + 10^(L2/10)), which adds acoustic powers logarithmically. This is critical in acoustics when dealing with simultaneous noise sources like industrial machinery or live music events.
The formula converts SPL values to acoustic power (10^(L/10)), sums the powers, and converts back to logarithmic scale. Directly adding decibel values is incorrect because the logarithmic scale is non-linear. For example, two 80 dB sounds result in 83 dB, not 160 dB.
Use this tool for acoustic insulation planning, noise analysis in built environments, or sound system design. Note: both inputs must be in the same unit (dB SPL), and source order does not affect the result.
Frequently asked questions
How does this formula differ from direct dB addition?
The logarithmic scale requires converting values to power before summation. Direct dB addition does not reflect actual sound perception.
Can I use this calculator for more than two sources?
No, this version is for two sources only. For multiple sources, sequentially sum powers using equivalent formulas.
What if the sources have different frequencies?
The calculator assumes levels are already weighted for audible frequencies (like dB(A)). For pure tones, use spectral analysis.
Why doesn't source order matter?
Power summation is commutative, so L1 + L2 equals L2 + L1 in the formula.