Every appliance and fixture that's plugged into your house's electrical system contributes some form of distortion to the quality of the power. Your entertainment system is victim to all of those impurities, which manifest themselves as haze, low-level noise, flicker and a loss of fine details in the audio and video signals. Computers, dimmers, air conditioners, microwaves and vacuums are examples of the worst culprits. Thankfully, these problems are easily corrected -- and the performance of your system greatly improved -- by installing a power line conditioner.

A quality PLC will filter out most of the pollution from the AC circuit, passing along only clean, noise-free power to your components. The most advanced units will regenerate entirely new power for the ultimate in playback fidelity.

Prices start around $300.