You can upgrade your car stereo yourself, but how can you be sure that your new system is set up properly? This is where a professional comes in. An experienced technician can install your new car audio system and get you up and running in no time. However, you need to be aware of a few mistakes that will severely compromise the quality of your sound. The first mistake is pairing high-power equipment with a low-quality power source. This will result in a loss of sound quality, and can end up being a costly mistake.