How Magnets Work in Earphones

When people listen to music, they notice the bass blaring through their headphones or the beat of the drum. What people don't think about is how headphones are able to carry the sound from your iPod or computer to the headphones. People don't think about what makes their headphones work. There's a lot more to it than plugging them into your iPod.



History:

Headphones were first created in the 1930s by Beyerdynamic.

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Making A Speaker:
Even though earphones and speakers are different, the basic/fundamental composition of the two are similar. They include the similar components, and earphones are essentially smaller, more contained speakers. Speakers have cones inside, but headphones have a diaphragm (a vibrating plastic) instead. Like speakers, however, headphones have a similar design: the metal coil is just above the magnet. Because the way/design of speakers are similar to headphones, we constructed a model speaker to better explain how headphones function.


This is how we made a speaker.

Materials Needed To Make a Speaker:

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Coil of Wire
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Magnet


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Audio Cable(To plug into computer/music device)
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Cup or Can


To make a speaker, you first need to gather the following materials: a coil of wire, a magnet, a cup or can, and an audio cable. First, attach the coil of wire to the outside bottom of the cup or can, using tape or a rubber band. Make sure you leave the two ends of the coiled wire free, because these will be necessary to connect to the audio cable. Next, tape the magnet on top of the wire coil, in between the two ends of the wire. Finally, wrap the loose ends of the audio cable wires to the two ends of the wire coil. The end result should look like this:



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Finished Speaker
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Make sure each copper wire from the audio cable is attached to each end of the red wire coil separately
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Speaker Close-Up



Pay close attention from 2:04-3:20.



Explanation:


http://electronics.howstuffworks.com/speaker6.htm
Look at the above website to see how a speaker works. Remember that headphones are essentially just a smaller, more contained speaker. The magnet and the coil within the speaker has the same function within headphones.

Headphones are made up of several parts: the enclosure, the outer part of the headphone which amplifies sound and keeps the whole thing together, the magnet attached to the enclosure, the metal coil, and the diaphragm.
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Enclosure
Enclosure





Like the speaker we constructed, a headphone contains a metal coil and a magnet. The coil sits in front of the magnet and the coil is connected to the wires that connect the headphone to the music player. When electricity (audio wave) travels from the iPod or mp3 to the coil, the coil becomes magnetically charged(electromagnet). The charged coil, now also a magnet, then comes in contact with the original magnet, causing them to rotate between repelling and attracting each other. This rotation causes the diaphragm of the headphone to alternate between moving upwards and downwards. This movement creates vibration, which produces waves and pumps sound waves out from the speaker into the room, or in our case, straight into our ears.

Pay Close Attention to 1:05-1:25 and 2:13-2:30



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headphones

Our ears interpret different vibration speeds as different pitches. When the diaphragm of the headphone moves rapidly, we hear higher pitch. Likewise, when the diaphragm moves slowly, we hear lower pitch. Volume is also affected by vibration. The larger the vibration force, the louder the sound.





Bibliography

http://www.ehow.com/facts_7254429_do-headphones-work-magnets_.html
http://www.ehow.com/how-does_4896025_headphones-work.html
http://www.best-headphone-review.com/howheadphoneswork.html
http://electronics.howstuffworks.com/speaker6.htm