You could hire a professional to come in and tweak your home theater setup for a couple hundred bucks. Or you could just download THX Tune-Up ($Free). This simple app can help you get the aspect ratio, brightness, contrast, color, and tint of your display set correctly by taking control of your Apple TV and using the camera on your iPhone, iPad, or iPod touch to display a special color filter. It can also help ensure that your speaker assignment and speaker phase connections are correct. Oh, and did we mention it's free?