Ever had this experience? A friend drives over to show off the expensive new audio system in his vehicle. He slides in a CD and cranks it up, waiting for your reaction. The music hits you, and, even though his system cost more than your entire car, it sounds terrible! The highs are too bright, the bass is boomy, and you can't hear the vocals through all the nastiness. What's up with that?

Whether you're a car audio novice or a seasoned competitor, these discs can help you find and cure weaknesses in your audio system.

There's a science to tuning audio components to work well together. In the early 1990s, Autosound 2000 (a company founded by noted car audio experts Richard Clark and David Navone) created a series of five test discs to help you diagnose and cure problems in your audio system:

• CD101: Low Frequency Test CD
• CD102: Set Up and Evaluation of Sound System Imaging and Placement
• CD103: Evaluating Audio Components, Listening Environments, & your Listening Ability
• CD104: The Ultimate Amplifier Level Setting Disc
• CD105: Road Noise, System Noise, and Frequency Range Demonstrations

The titles alone are intimidating, and a quick look at the liner notes included with each disc will remind you of classes that you dropped after the first day of school. I usually tune my system by ear, but I'd heard good things about these discs, so, armed with all five of them, I set out to evaluate the modest audio system in my Jeep Cherokee.