This Recommendation describes the methodology for deriving equipment impairment factors (Ies)from subjective listening-only tests. It is intended that it primarily be applied to determining Ies fordigital signal processing devices used in the network that have not otherwise been covered by the E-model. The equipment impairment factors derived by this methodology are intended to be used in the E-model (see ITU-T Recommendation G.107). They will reflect the auditory impairments of the corresponding equipment in a listening-only mode.