A type of loudspeaker based on the properties of piezoelectric crystals (polyester or ceramic), which deform when receiving a voltage between their faces and which, acting as an electroacoustic transducer, are used for sound reproduction. If a flared cone is attached to one of its faces, it will undergo a displacement capable of producing an oscillating pressure within an audible frequency range, i.e., low frequency. These loudspeakers are simple, cheap and able to radiate with very little electrical power.
