Keep in mind two important factors when thinking of purchasing new car audio speakers. You will need to know a bit about your car stereo in terms of its power output. This is because the car stereo power can directly affect audio speakers sensitivity and power handling. If a car stereo has high power output, you will need lower sensitivity speakers with higher power handling. If a car audio speakers has low power output, you will need higher sensitivity speakers with lower power handling needs. This can seem a bit confusing to understand at first, but just try to get a good grasp on the car stereo power and then you can figure out your speaker needs from there without worries.
Depending on how fancy you want to get, there are full range car audio speaker packages that provide you everything you need in one place. With full range speakers you will know you are getting parts that work well together and can maximize your speaker and stereo output. Full range speakers come with built in woofers to emphasize lower notes, voices, and instruments and tweeters that emphasize the higher notes and sounds. Some full range speakers will come with options like midrange enhancers or a super tweeter! This will help you really tweak all the aspects of your sound. Keep in mind that full range speakers are the easiest option to install and can be found inexpensively, as they often are made to fit right into factory specs.