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Wednesday, 17 August 2011

Speakers - How They Work,Simplified

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One of modern science's most used and least appreciated item is the noble speaker. We have a little speaker in our cars,mobiles,laptops,mp3 players,televisions,etc., but we seldom wait and think how it really produces sound. Lets break down a speaker into the basics.

 It is common knowledge that sound is caused by the vibration of air.Air is full molecules and when the molecules are hit at one side, it passes the energy to the molecules near it. (Think of air as the sand spread on a beach, if you hit the ground with a stick, the grains near the spot vibrate and fly). And any sound that occurs has a characteristic frequency according to it's vibration.

Now lets consider the actual speakers. The main parts of a speaker are :- a thing that vibrates (diaphragm), a thing that tells in what particular way to vibrate (driver) and a pair of magnets to actually make the vibration.
The diaphragm is the part of the speaker which seems like thin paper and actually vibrates to make the sound.  There is an electromagnet (which is a magnet whose intensity and poles are controlled by the electricity flowing in it) and a permanent magnet (the normal kind of magnet which doesn't change any of it's properties) inside the speaker.

The electromagnet is fixed to the rear of the diaphragm, and the permanent magnet is placed just behind the electromagnet. Now when current is applied in opposite directions through the electromagnet, the poles keep on changing. Here the well-known fact - like poles repel and opposites attract, comes into action. The attraction and repulsion of the electromagnet between the permanent magnet causes a vibrating motion, which is passed on to the diaphragm, which vibrates the air molecules and makes sound.

The driver understands how the vibration should be made from the disk or cable network signal, whichever is your source for the sound. The digital information in the disks and signals gets converted into corresponding electric signals by the driver and gets sent to the electromagnet.

Your ear acts like a speaker in reverse and converts the vibrations back into electric signals in your brain. Thats how your favorite music gets played. :-)
To know how the picture comes on a television, read