Effects of harmonics on relative pitch discrimination in a musical context

The contribution of different harmonics to pitch salience in a musical context was examined by requiring subjects to discriminate a small (1/4 semitone) pitch change in one note of a melody that repeated in transposition. In Experiment 1, performance was superior when more harmonics were present (first five vs. fundamental alone) and when the second harmonic (of tones consisting of the first two harmonics) was in tune compared with when it was out of tune. In Experiment 2, the effects of harmonics 6 and 8, which stand in octave-equivalent simple ratios to the fundamental (2∶3 and 1∶2, respectively) were compared with harmonics 5 and 7, which stand in more complex ratios (4:5 and 4:7, respectively). When the harmonics fused into a single percept (tones consisting of harmonics 1, 2, and one of 5, 6, 7, or 8), performance was higher when harmonics 6 or 8 were present than when harmonics 5 or 7 were present. When the harmonics did not fuse into a single percept (tones consisting of the fundamental and one of 5, 6, 7, or 8), there was no effect of ratio simplicity.