An implantable medical device comprising a housing and a limiting structure defining a resonant region in the housing. An acoustic transducer is connected to the limiting structure and extends into the resonant region so that the resonant region mechanically amplifies the deformation of the acoustic transducer at a resonant frequency. An implantable medical device comprising a housing and a limiting structure defining a resonant region in the housing. An acoustic transducer having the shape of a beam is mechanically coupled to the limiting structure and partially extends into the resonant region so that the resonant region mechanically amplifies the deformation of the acoustic transducer at a resonant frequency. An implantable medical device comprising a housing, an acoustic transducer coupled to the housing, and a means for mechanically amplifying the deformation of the acoustic transducer at a resonant frequency. The means defines a resonant region in the housing.