What are tweeter speakers?

Why do my car tweeter speakers crackle even when the stereo is off?

• I thought well maybe the stereo is hooked up wrong so I removed it from my car. Now I have no stereo at all and the tweeter speakers still crackle and produce a static sound. There are no exposed wires, no cracks or cut wires. Everything looks neat and tidy. Its only the front tweeters that make the static sound. So if my car is off and no stereo is hooked up why are the tweeter speakers still making the static sound. This just started a few weeks ago.

• Answer:

  Speakers are electromagnetic. They move based on moving a magnet through a coil as the coil changes the magnetic field. If there are other magnetic fields it can cause the speakers to make noises. Does it only do it while the car is running? I'm guessing it does, which means your speakers are picking up the sound from the alternator. You'll need to install a filter on the speakers that allows the noise to pass and forces the music through the speakers. You can test to see if this is true by shorting the speaker wires together (while they are not plugged into anything other than the speaker). Drive around and you won't have any noise.