Question

Inside a speaker:
1. Cone
2. Electromagnet (coil)
3. Permanent magnet

Explai the individual elements of the speaker and how they work together to produce sound?

Answer 1

1. The cone (also called Diaphragm) is made up from a light and strong material which develops vibrations by moving back and forth. This is similar to how a drum has a diaphragm on wich the drummer hits. One can see it vibrating. The same happens in a speaker. If visible one can see the cone vibrating as that is how sound gets produced. We know that sound waves are series of compressions and rarefactions that travel. A vibrating material produces the same.

2,3. Electromagnet and Permanent Magnet- - A drummer physically hits it that is a mechanical input is provided. A force is required here also but it is not of the same nature. The force is magnetic force that is controlled by electricity. The coil is attached to the cone. When current is passed through the coil it generates a magnetic field. This magnetic field interacts with the magnetic field produced by the permanent magnet that is placed in the vicinity. Think about having two magnets. One is placed on the floor and when one moves the other above it, the other experiences a force and tends to get attracted or repelled and hence moves. What if rather than moving the magnet over the other, one could change the strength of the magnet? This would change the magnetic force. Similarly here the coil experiences force based on how much current is flowing through the coil and because it is attached to the cone, it determines the amplitude of vibration of the cone and that determines the characteristics (amplitude and frequency) of the sound produced.