Pitch Classes Differ with Respect to Height

The pitch of a tone is considered to consist of two components: the rectilinear component of height and the circular component of chroma, or pitch class. In an experiment employing simultaneous sequences of Shepard tones, it is shown that tones in different positions on the chroma circle differ in height when generated under the same spectral amplitude envelope. Further, the directions of these differences remain constant when the envelope is centered at different positions along the spectrum, resulting in clear differences in the overall heights of the patterns.