App: Twelve Tone
Developer: Patrick Q. Kelly
Genres: Music, Education

A music composition / analysis tool.

Create a tone row by clicking on the staff or the piano keyboard. Twelve Tone will automatically create the Prime, Inversion, Retrograde, and Retrograde Inversion Magic Square. 

Save your rows or pitch class sets of 1 to 12 tones, with its name, current P, R, I, RI matrix markings, derivation and preferred accidentals settings. 

Save and Share PDFs of the notation, magic square, circular diagram, and piano representation of the tone row or set.

Drive your own software or hardware synth via MIDI to hear the instrument you want, or use the app's own acoustic piano.

Twelve Tone lets you know if any notes are repeated by highlighting both notes. 

Press the play button and hear your set played back with your selected rhythm.
Select what form(s) of the row you want played (once or looped); 
• Prime
• Prime then Retrograde
• Retrograde then Prime
• Retrograde
• Inversion
• Inversion then Retrograde Inversion
• Retrograde Inversion then Inversion
• Retrograde Inversion
Select the transposition interval and direction when looping playback. 

Hear the pitches as you mark them in the magic square. The marks indicate the row form in which the pitch belonged; Prime, Inversion, Retrograde, and Retrograde Inversion. 

Lock the square to avoid accidentally marking or unmarking notes, and erase the entire square with the touch of a button. 
Lock the prime row notation and transpose it to C to use the Absolute Pitch Method for labeling in the matrix. 

Comes preloaded with the following rows: 
Alban Berg's Lyric Suite
Babbitt's Composition for Four Instruments 
Schoenberg's Variations for Orchestra Op.31 
Schoenberg's Piano Piece Op.33a 
Webern's Concerto Op.24 
Webern's Piano Variations Op.27 
Webern's String Quartet Op.28

Release notes:
Added MIDI out. Send MIDI note on/off commands to external apps like Apple's GarageBand® or connected external MIDI hardware.
Bug fixes and stability improvements.