Speakers turn electrical energy into mechanical energy to move air, using a permanent magnet and an electromagnet. The electromagnet is energized when the radio or amplifier (if equipped) delivers current to the voice coil on the speaker. The voice coil will form a north and south pole that will cause the voice coil and the speaker cone to move in relation to the permanent magnet. The current delivered to the car speaker is rapidly changing alternating current (A/C). This causes the speaker cone to move in two directions, producing sound. These original equipment car speakers have been manufactured to fit your specific GM vehicle, providing the same performance, durability, and service life you expect from General Motors.