A magnet shoving paper
How Does a Speaker Make Sound?
A speaker turns a recorded wobble into current, which drives a coil and magnet to push air.
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Step 1 of 5
Sound is moving air, so something must move.
There is no way to make a noise without physically shifting air. Every speaker ever built is a machine for pushing air in a controlled pattern.
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Step 2 of 5
Current through a coil makes a magnet.
Wrap wire into a coil and send current through it and the whole coil behaves like a bar magnet, with a north and south end of its own.
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Step 3 of 5
Two magnets can push or pull.
The coil sits inside a permanent magnet. Send current one way and it is dragged inward; reverse the current and it is shoved back out.
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Step 4 of 5
The recording tells the coil how to move.
The stored waveform is turned into a current that rises and falls in exactly the same shape, so the cone traces the original sound.
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Step 5 of 5
Big cones move air; small cones move fast.
Deep notes need a lot of air shifted slowly, which suits a large cone. High notes need tiny, very rapid movements, which only a small cone manages.
A cone playing a deep 40 hertz note travels in and out 40 times every second, sometimes moving more than a centimetre each way.
The short version
A speaker makes sound by turning a recorded wobble into current, which drives a coil and magnet to shove a cone at the air.
Try it yourself
Rest your fingertips lightly on a speaker playing bass. You can feel the cone travelling in and out under your skin.
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