Percentile sound levels such as L10, L50, L90 and L95 (LA90 as the background noise level) are often converted into an equivalent level Leq, subtracted from one another, added logarithmically, or averaged across measurement windows. This page computes what such operations actually establish: the complete range of values compatible with the reported levels, with endpoint status, as proved in the article cited above. It replaces single-number conversions (a fixed L90 to Leq offset, logarithmic addition of L90 values, the ISO 1996-2 L95 substitution) by the identified range, and reads complete time histories exactly.
Operations
Each operation returns the identification set of the paper in the reporting form of Section 7.6: target, observation basis, inputs, classification, assumptions used, identified result with endpoint status, and the representativeness entry. Levels are shown to decimals; energies are exact rationals and can be shown with .