How does a speaker work?

Answer 1

A speaker is essentially an air pump. I like to say the bigger the pump the bigger the sound!!!

A driver is a device that reproduces sound. Drivers consist of woofers, subwoofers, tweeters, midranges, compression horns etc. A driver consists of a magnet assembly, a metal or composite basket/frame, coil and cone or dome.

A driver has a coil of wire that is electrically attached to your amplifier. The coil is the electro magnet not the magnet itself. The magnet is usually made of ceramic but used to be made of Alnico (Aluminum, Nickel, Cobalt; expensive compared to ceramic) and is more often now made of neodymium (a lighter stronger material than ceramic). The magnet has a permanent magnetic polarity that does not change. When the coil of wire is placed inside the magnet assembly "pole piece" and an alternating signal is placed thru the coil it will cause the coil to oscillate as the coil will now attract and repel within the magnet assembly as the polarity changes on the coil. The coil is attached to a cone (or dome in the case of tweeters and some midranges) which is capable of moving air more effectively.

Speakers consist of these drivers usually a woofer, a tweeter, and sometimes a midrange. A speaker will almost always also have a crossover network which is basically a filter network that effectively divides the signals to each driver so that the bass only goes to the woofers and the high freq only goes to the tweeters.

Fun fact for the day...a microphone is basically a small driver that operates in reverse. You speak into the diaphragm that then moves the coil which creates an alternating current replication of your voice which can be amplified and reproduced thru a speaker. Nifty!!!

HOPE THIS HELPS!!

Answer 2

visit
http://electronics.howstuffworks.com/speaker.htm

for full explanation.