The dependence of perceived loudness on frequency, duration and bandwidth of sounds is briefly reviewed. The implementation of these dependencies in sound level meters and loudness meters is discussed. The main features of a loudness meter in accordance with ISO 532 B are illustrated. In particular, the simulation of the duration-dependent decay of psychoacoustic excitation is addressed. Finally, the subjective evaluation of the loudness of different types of printers is compared to their objective rating according to A-weighted sound power and loudness measured with a loudness meter.