scope:

This Technical Report describes an alternate background noise correction that depends not only on mean background noise proximity to measured source levels, like the standard background noise corrections of ISO 3741, ISO 3744, ISO 3745, and ISO 11201, but also on the steadiness of the background noise. Like the standard background noise corrections, the alternate background noise correction tends to increase as the background noise level approaches the measured source level, but the alternate background noise correction also increases with the steadiness of the background noise, unlike the standard background noise corrections.