White Paper - Loudness Metering
Unfortunately, it has become normal and necessary to re-adjust the loudness when “zapping” between channels. The same variance in loudness sometimes occurs at the beginning of TV commercials. Not surprisingly, viewers have complained about these variances in TV programming repeatedly. They are caused by many factors, but there is one common denominator: until today, there is no solution to measure the subjective parameters of loudness perception objectively and precisely. Measuring equipment currently used in audio production does not allow for an assessment of the subjective parameter loudness. Rather, the devices are designed to show the peak voltage of an audio signal, making it impossible to assess the subjective loudness. Quasi Peak Programme Meters (QPPM) are very commonly used among broadcasters. However, with an integration time of 10ms (cf. ARD specifications [Pf3/6]) they are unable to display real peaks. Yet, the detection of these is essential for work involving digital signals.