Pitch-class counts


Three plots are shown for each musical work. The first two plots measure the amount of pitch classes for the entire work: the plot on the left measures pitches by duration, and the one on the right counts pitches by note attacks. Every voice is given a different color so that you can see the contribution of that voice to the the total for each pitch class. The final note (or final chord root) is labeled on each plot.

The triangular pitchscape plot underneath the two histograms displays changes in the most common pitch class throughout the piece. The keyboard underneath the pitchscape shows the color to pitch-class mappings. Notice that the most common pitch class in the duration-weighted histogram (the highest bar in the plot above, left) is the pitch class represented at the apex of the pitchscape plot. The final note is shown at the bottom right corner of the plot.

Time in the music goes from left-to-right in the pitchscape plot with tick-marks under the triangle representing barlines in the score. Every point in the plot represent a specific time range in the music, with higher points encompassing more of the music and lower points shorter excerpts of the music. Imagine scaling the large triangular shape of the plot to a specific point in the plot: the bottom of this scaled triangle indicates the range of music that the point represents.

Each pitch class can be displayed in two different shades that indicates which is greater of the major or minor third above the most common pitch. For example, darker purple indicates that A is the most common pitch class and C is more common that C♯; while light purple means A is the most common pitch class and C♯ is more common than C. This shading can sometimes help to see cadence points in the pitchscape where an A major triad is used when otherwise an A minor triad may be expected from the key signature.