To put it very simply, your earphone includes a piece of plastic that vibrates in accordance to the signals received from the device it’s attached to. The plastic moves due to a metal coil that’s attached to a magnet, which allows the plastic to form the sound waves that pass into your ear.
That’s it, really. It seems easy enough, but I couldn’t have thought of it.
Jezen Thomas at eHow.com provides a more detailed explanation to us, he says that,
“Earphones consist of a speaker cone, an iron coil, a magnet and speaker cables. When earphones are plugged into a music-playing device like a stereo, electricity is sent along the speaker cables. The speaker cables feed this electrical current through the iron coil, which behaves as an electromagnet. The coil then attracts or repels the permanent magnet, depending on the electrical current sent by the music-playing device. This causes the coil to move, which subsequently pushes and pulls the speaker cone. As the speaker cone vibrates as a result of this movement, it creates sonic waves that resonate through the air and are transferred through small bones and membranes inside your ear”.
Of course, there are different types of earphones, but basically, that’s it.
Some earphones, however, do feature additional functions. Noise-canceling headsets, for example, can generate a small field of white noise around the speaker itself, which acts as something of a vacuum and has the effect of disabling outside noise. These headphones are also better for the health of your inner ear than most other types. Sam Costello at About.com writes,
“The noise around us can contribute to cause us to change how we listen to an iPod. If there’s a lot of noise nearby, it’s likely that we’ll turn up the iPod’s volume, thus increasing the chances of hearing loss. To cut down on, or eliminate, ambient noise, use noise-deadening or –cancelling headphones. They’re more expensive, but your ears will thank you”.
Chris Woodford, writing for ‘Explain That Stuff.com’, gives a detailed description of the main differences between earphones and speakers. Despite essentially operating in the same way, there are variations between the two, it seems. He says,
“The biggest difference between loudspeakers and headphones is, of course, size. A loudspeaker needs to set all the air moving in a room so you can hear the sound it’s making, but the speaker in a headphone only has to move the volume of air inside your ear canal. That’s why it can be so much smaller and more discreet”.
If, even after all this tech talk, you’re still interested in seeing what’s going on in your headphones, the Youtube user Cayde Brown has a series of videos called ‘Take Apart’, which will probably be of interest. In one episode, Cayde takes a pair of headphones apart and shows us exactly how they work.