Real-time Visualisation of Loudness along Different Time Scales

We propose a set of design criteria for visualising loudness features of an audio signal, measured along different time scales. A novel real-time loudness meter, based on these criteria, is presented. The meter simultaneously shows short-term loudness, long-term loudness and peak level. The short-term loudness is displayed using a circular bar graph. The meter displays the longterm loudness by means of a circular envelope graph, organized according to an absolute time-scale – looking similar to a radar display. Typically, the loudness measured during the past hour is visible. The algorithms underlying the meter's loudness and peak level measurements take into account recent ITU-R recommendations and research into loudness modelling.