Standards

For more specific applications, the ACR method has its own standard.

The ACR method is used to evaluate overall sound quality. It is often used in the domain of telecommunications and audio system quality evaluation. The ACR method test method is described by the International Telecommunication Union in the standard "ITU-T-P.800: Methods for subjective determination of transmission quality". This standard provides a general 5-category quality scale ("Excellent", "Good", "Fair", "Poor", "Bad"). In the analysis, each category will be associated to a numeric score. For example, in the case of the 5-category scale mentioned before: Excellent= 5; Good = 4; Fair = 3; Poor = 2; Bad = 1. The arithmetic mean of this score for a given sound is called the mean opinion score (MOS).