ITU-T P.700 PDF

This Recommendation describes a loudness model which applies for all telephony audio bandwidths from narrowband (NB), wideband (WB), super-wideband (SWB) to fullband (FB), and for all types of terminals, including handset, headset, hands-free and conference terminals.

It is foreseen that the current ITU-T loudness rating (LR) model, as described in [ITU-T P.79] will be used in parallel with the loudness model given in this Recommendation for an extended period of time, since it is anticipated that network planning will continue to have a preference towards loudness rating calculations according to ITU-T P.79.