Summary

Recommendation ITU-T P.700 describes a unified method required for calculating loudness, allowing comparison of narrowband (300-3.4 kHz), wideband (100-8 kHz), super-wideband (50-14 kHz) and fullband (10-20 kHz) telephony for all types of terminals including handset, hands-free and conference terminals.

The model described in this Recommendation is consistent when switching from one bandwidth to another and independent of the listening situation (e.g., handset, headset, hands-free) with regards to producing a constant perceived loudness.

Compared with loudness rating models, such as the one presented in Recommendation ITU-T P.79, the present method predicts the absolute loudness, considers auditory masking and is applicable to a wide range of acoustic levels.

This Recommendation incorporates an annex and a number of appendices that contain test vectors for the validation of loudness model implementations and descriptions and results of the loudness experiments that form the basis for this Recommendation.