n.
or speaker
In sound reproduction, device for converting electrical energy into acoustical (sound) signal energy that is radiated into a room or open air (see acoustics ).
The part of the speaker that converts electrical into mechanical energy is frequently called the motor, or voice coil. The motor vibrates a diaphragm that vibrates the air in immediate contact with it, producing a sound wave corresponding to the pattern of the original speech, music, or other acoustic signal.