New ECMA-425 statistical background correction standard

In December 2024 Ecma published the new ECMA-425 standard “Statistical background correction for information technology and telecommunications equipment noise measurements”. The statistical background correction (SBC) is an alternative to the standardized legacy background correction (LBC) K1 that upper bounds the true source with specified confidence. The SBC contains an additional background steadiness parameter along with the measured source-background level difference parameter common to both the SBC and LBC. The SBC is most appealing for grade 1 and 2 measurement methods. SBC benefits are described: 1) lower background-corrected source levels for steady backgrounds near the measured source, 2) prohibition of background corrections for unsteady backgrounds, and 3) elimination of the “grade penalty” that disincentivizes precision grade 1 measurement methods. The procedures in ECMA-425 for sampling background noise and implementing the SBC are presented. A plan for further SBC integration into acoustic noise measurement standards is proposed.