Speakers are the basis of any car audio system; without them, you'll hear nary a thing but wind, the hum of the engine and the bustle of traffic. With speakers, our cars come alive with music. They work by translating the electrical signals from an input like a CD into vibrations that our ear registers as sound.
Not all car speaker systems are alike. There are two primary classifications of car speakers: coaxial and component. Coaxial speakers are what you'll commonly find in a factory-installed car audio setup -- in other words, unless you've installed a custom audio kit in your car, it likely has coaxial speakers. A coaxial speaker consists of a woofer that produces low- and mid-range sounds and a tweeter that sits atop the woofer producing high range sound. Superior coaxial units will add extra tweeters to better reproduce the high range sound.
Component speakers are comprised of several separate units -- the woofers and tweeters are not built together into one part. Component speakers also utilize a crossover network to direct sound to the right speaker units, producing superior sound quality. The crossover network helps component speakers deliver better audio than you'll get from an average coaxial setup. Because of that advanced crossover network, component systems don't need as many tweeters as coaxials to produce high-quality sound -- a two-way component speaker setup is as good or better than three-way, four-way or five-way coaxial speakers. Not surprisingly, component speaker systems can be pricier than coaxial speakers. No matter which kind of speaker system you're interested in, there's a huge price range: Inexpensive coaxial and component sets can be had for $20 to $40, but high-end gear can cost in the hundreds of dollars -- or more! Look for some popular audio brands like JL Audio, Alpine and Infinity.