Vibrations caused by bed load passing over a metal plate are registered by a so-called hydrophone sensing device and are then evaluated in a simple manner by a pulse counter. In order to be able to calibrate this indirect measuring method, it is necessary to determine the transported bed loads by direct measurement as well. On a two-year measuring programme performed on a water intake in the Pitzbach stream in Austria, valuable data has been acquired, which is now compared with other calibration measurements from a hydrological torrent test area in Switzerland.