To improve the stereo system in a vehicle, aftermarket speakers are usually used to replace the stock speakers in the car. While most car speakers can be swapped out with ease, additional components such as tweeters and subwoofers can be integrated to further improve sound quality.

A car stereo can be modified a number of ways. The first step in improving a car's sound system is replacing the radio, or head unit. This is the radio/CD player located in the car's dash. An aftermarket unit will provide more power to the speakers and generally be of better quality than most factory head units.

The next step is replacing the car stereo's speakers. Most cars will have a four speaker system with two speakers up front and two in the back. Unless the vehicle is equipped with a premium system from the factory (such as Bose), aftermarket speakers will improve sound over moderate factory installed components.c

Adding booming bass to a car is popular among car audio enthusiasts. Subwoofers (pictured right) can be added to a sound system, often being located in the vehicle's trunk. Subwoofers commonly range in sizes of 8, 10, 12 and 15 inches and are connected to amplifiers to provide high wattage for louder bass.

Improve your system's clarity by installing a set of tweeters. These small, high-frequency speakers help "place" your music accurately in your listening space. Prices range from around $50 to $450.c

For the car audio lovers, component speaker systems consist of separate woofers, tweeters and crossovers designed for superior performance. The tweeter is mounted closer to your ears, so you hear all the details in your music. Prices range from around $70 to $5,500.c

Custom-fit speakers are too large to fit in any traditional speaker opening, so they require modifications to your vehicle. But, once they're installed, you'll be impressed by the big sound. Prices range from around $130 to $280.c

For your in-vehicle video enjoyment, center channel speakers improve the clarity of the dialogue in your programs. Prices are around the $140 range.c

• 6-1/2" range in price from around $45 to $900.c
  
• 6"x9" range in price from around $45 to $380.c
  
• 5"x7"/6"x8" range in price from around $50 to $740.c
  
• 6-3/4" range in price from around $45 to $5,500.c
  
• 3-1/2" range in price from around $40 to $150.c
  
• 5-1/4" range in price from around $50 to $4,300.c
  
• 5" are around $90.c
  
• 4"x10" range in price from around $70 to $110.c
  
• 4"x6" range in price from around $50 to $140.c
  
• 4" range in price from around $50 to $700.c