This free 12-tone Matrix Calculator is perfect for musicians who wish to experiment with melody and harmony using the techniques of atonal tone rows. The Post Tonal Calculator allows you to choose notes or generate them randomly, explore sequences of intervals as short as 3 tones and as long as a twelve-tone tone row. The Post Tonal Matrix Calculator will then generate a matrix of tone rows based on your primary row, giving you all of the possible interval-consistent prime rows, retrograde, inversions, and retrograde-inversions.