If you have Sonos speakers for your home theater system you may want to check out Sonos Trueplay. The app will link to your speakers and tune each one by using your iPhone/iPad microphone. It sounds like a great option for better sound without having to place speakers in sound optimal (which isn't always wife optimal) positions or if you have a more odd shaped living room.
http://www.techradar.com/us/news/audio/sonos-truesound-app-will-turn-you-into-an-acoustic-engineer-1305281