Answer: any speaker that can convert electrical energy into sound energy is usually called loudspeaker. Loudspeakers are not only used in civil and engineering speakers, but also called loudspeakers, buzzer and so on. There are many categories of loudspeakers. According to their energy exchange principle, they can be divided into electrostatic (capacitive), pneumatic, electric, piezoelectric, electromagnetic, and ion discharge loudspeakers. Loudspeakers for general speakers are more electric and electrostatic. The shape of the loudspeaker is: conical, spherical top, horn, plate and so on.