A sound-generating device comprises a first enclosure having at least one first electrode and a first piezoelectric layer, a first terminal of an audio signal output being coupled to the at least one first electrode of the first enclosure, a second enclosure having at least one first electrode and a first piezoelectric layer, and a first bendable element coupled between the first and second enclosures. The at least one first electrode is coupled with the first terminal of the audio signal output. The first piezoelectric layer of the first enclosure and the first piezoelectric layer of the second enclosure are configured to respond to the signal supplied by the audio signal output and to generate sound waves.