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Name: harden
Status: N/A
Age: N/A
Location: N/A
Country: N/A
Date: Around 1993

Why is there a permanent magnet in a speaker?

There are actually two magnets in a common audio speaker. There is one permanent magnet attached to the framework of the speaker, and one electromagnet attached to the cone of the speaker (usually mylar now instead of paper). The wires that go to the coil of wire on the pack of the cone supply the current to an air core coil, which produces an electric field that either repels or attracts to the permanent magnet, depending on the instantaneous polarity. The higher the frequency of the electric current being sent by the amplifier, the faster the field is set-up, broken down, and re-set-up in the other direction, so the faster the cone moves back and forth. Because all the cone does is move air, if it is moved back and forth fast, you hear a high tone from the vibration. Low frequency current, low frequency tone. Large amount of current, big movements of the coil and cone, producing loud tones, and small amounts of current will produce small movements of the cone. Now the only trouble is a thing called impedance, but that is for another discussion.


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