An electronic drum includes a pad to be beaten with sticks, a circular
piezoelectric converter for converting stress to an electric signal and a
semi-circular filter element adhered at one surface to the pad and at the
other surface to the circular piezoelectric converter; the circular
piezoelectric converter is partially held in contact with the
semi-circular filter element and partially overhung under the pad; when
the vibrations reach the filter element, the filter element eliminates
high frequency vibration components from the vibrations, and transmits
them to the half of the circular piezoelectric converter; the vibrations
give rise to bending stress in the half of the piezoelectric converter
held in contact with the filter element, and shake the other half of the
piezoelectric converter; this results in enlargement of the bending
stress, and the electric signal with a wide amplitude is taken out from
the piezoelectric converter.