Using a compatible iPhone, iPod Touch, iPad, or iPad mini, users can access several tests (including the famous "Deep Note") that will help you tweak both the audio performance of your home theater system (speaker assignment and speaker phase tests for both 2 and 5.1 channel systems are provided), and the video performance of your TV. Video calibration test patterns for aspect ratio, brightness, contrast, color, and tint are provided. In addition, an iPhone or iPad's built-in camera is also employed for performing the color and tint adjustments.
In addition to the tests, the app also provides users with access to a library of THX movie and video trailers, still photos, as well as an "Ask Tex" feature that allows users to get answers to questions regarding the THX Tune-Up. The app even invites users to provide feedback back to THX.
The app is now available and can be downloaded free through February 4, 2013, via the iTunes Store. After February 4th, the app will be priced at $1.99.
To connect your iPhone or iPad to a TV, you will also need either an Apple Digital AV Adapter (compare prices) or Lighting Digital AV adapter (compare prices) with HDMI cable, or an Apple TV media streamer (compare prices).
Currently, only the iOS version is available. However, an Android Version is on the way. Also, the reason that audio tests are only provided for up to a 5.1 channel system is that iOS devices do not support 7.1 channel (or more) audio setup configurations.
For more details, in addition to those provided by the iTunes store, refer to the THX Tune-up FAQs. Image provided by THX, LTD
UPDATE 1/27/14: The THX Tune-Up App is now available for Android. The App is free worldwide from January 24th through February 3, 2014 - after which it will be priced at $1.99. THX Tune-Up Android Version App download page.