Spending time exploring the circle of fifths is a useful exercise for seeing the relationships between notes and key signatures. Circle Theory, by Artsiness, is a great iOS app for referencing and visualizing the circle of fifths.
The app’s interface has the primary circle displaying the current Tonic note/key signature. The additional information options are shown in the inner circle, which can help to display:
- Number of sharps or flats in a given key
- Notes of the triad associated with the key
- Relative minor key signature
- Roman numerals for the given key
There is also a transposition assistant which will let you transpose your primary key and display the associated tonics across the circle of fifths.
There is only so much you can do with the circle of fifths visually, and the folks at Artsiness have succeeded in creating a simple, easy to use and functional app. A very useful app for those that might need it.
Circle Theory is available for $4.99 from the App Store, and is a universal app (iPhone, iPod touch, and iPad). The app requires iOS 4.2 or later.
The company does not currently offer an Android version.