How Stuff Works

Speakers

Speakers convert electrical signals into physical vibrations, which create sound waves. The sound waves form when the speaker’s magnet attracts the positive end of an electromagnet and repels the negative end. As the elecromagnet’s polarity changes, it creates an alternating current that pushes the coil back and forth. When the coil moves, it shakes the speaker diaphragm, vibrating the air in front of it and creating sound waves. The rate and distance of coil movement determine the volume and pitch.

*

Suspension: Flexible rim allows the diaphragm to move.

Spider: Holds the voice coil in place.

Basket: Metal frame supports the driver.

Magnet: The magnet’s negative field forces the voice coil to change orientation as it attracts and repels the positive and negative poles.

Voice coil: Creates an alternating current within the speaker by moving back and forth rapidly.

Diaphragm: When the voice coil vibrates the flexible diaphragm, it produces sound waves.

*

Speaker Crossover

Most speakers contain different drivers--woofers, tweeters and mid-range--that produce sound waves of varying frequencies. Dividing an audio signal into low, high and mid-range frequencies, the speaker crossover channels frequencies to the appropriate driver.

* Tweeters: Small speakers produce high-frequency sounds.

* Mid-range: Produce frequencies in the middle of the sound spectrum.

* Woofers: Produce low-frequency sounds.

*

Source: www.howstuffworks.com

Researched by CHRISTINE FREY/Los Angeles Times