Here's something nice from those folks at THX. It's a free app (through February 4, then it's US$1.99) that allows you to assess the state of your home theater and make adjustments to improve audio and visual performance.
THX tune-up connects to your TV with the Apple Digital AV Adapter and an HDMI cable. You'll want the Lightning cable version if you have a newer device. It can also connect to your Apple TV with a wireless connection.
You can check your screen's aspect ratio, brightness, contrast color and tint. The app also uses your iOS camera to set color and tint with special built-in filters.
Audio tests include sample sounds to see if your speakers are hooked up in the proper surround locations and if they are in phase. Once you are finished the set up process, the app can play some really high-quality trailers, and the famous THX Deep Note in 5.1 surround.
I tried the THX tune-up app and it worked as advertised. The setups are pretty basic, but it is surprising how many home theaters are pretty out of tune. The app is not a substitute for a professional visit, but most home theaters will be improved.
The app is universal and runs on the iPhone 4 or above, the iPod touch (fifth generation) and the iPad 2 or above. The app is optimized for the iPhone 5 and requires iOS 5.
This is a pretty slick app if you're into home theater and movies, so grab it while it's free and enjoy.