Similarly, adding a sharp to the lower note of a major second will decrease the size of the second by a semitone, forming an minor second. Adding a flat to the lower note of a major second will increase the size of the second by a semitone, creating an augmented second. A double-sharp on the lower note of a major second will decrease the size of the second by two semitones, thereby forming a diminished second.

Example 14-3 illustrates how the addition of an accidental to the lower note of a natural interval changes the quality of the interval. Click, or click and hold, the arrow buttonss to select a natural interval and then click an accidental for the upper note.

Example 14-3