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Magnets in speakers
Name: harden
Status: N/A
Age: N/A
Location: N/A
Country: N/A
Date: Around 1993
Question:
Why is there a permanent magnet in a speaker?
Replies:
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.
dipper
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Update: June 2012
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