To adjust acoustic characteristics depending on the applications on every occasion by properly and simply changing the electroacoustic characteristics after manufactured or more advantageously when the capsule is assembled in a casing.

This invention relates to an electroacoustic capsule or electroacoustic transducer for an electroacoustic device. The electroacoustic capsule and/or electroacoustic transducer has electrostrictive or magnetostrictive elements (6, 7, 12, 21), more advantageously piezoelectric elements connected to a controllable power supply, dimensional changes of the electrostrictive or magnetostrictive elements by voltage control cause changes of the inner geometry of the electroacoustic capsule or electroacoustic transducer. This allows adjustment of the capsule or transducer to match the electroacoustic device in which it is mounted so that individual and dynamic adjustments are possible.