Bach’s organ pedal leaps create perceptual pitch ambiguity for listeners.

Evidence

The pedal line consists of a sequence of five descending scales with eight notes in each except the last. Each scale ends with an upward leap of a minor seventh, and the exact moment at which the upward leap occurs is often perceived with some ambiguity, even when listeners have the score in front of them. The strength of this effect depends on the particular stops used. This ambiguity is particularly common among listeners in the third bar of the extract, where the upward leap is often very strongly perceived as occurring one or even two notes later. This could be due to the entry of a new part in the left hand playing F3, which starts as the pedal part jumps up to written B♭3. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1645

Categorization

Category: Factual Claims

• XREF: Connects to the Shepard tone literature and how unambiguous written pitch can still be perceived ambiguously; ties to the reader’s listening-practice interests.
• SEED: Possible essay angle: classical composers who accidentally or deliberately exploited auditory illusions before they were systematized by 20th-century psychoacoustics.

Related

• Shepard-tone ambiguity arises in real music such as Bach’s organ works (similarity 0.88)
• Organ builders exploit missing-fundamental perception to create bass notes no pipe actually sounds (similarity 0.79)
• Composers can blur a musical event’s perceived timing by manipulating harmonic-series membership (similarity 0.78)

Broader Connections

• Listeners reconstruct a perceived pitch that is not physically present #expands (0.75) — David Howard, Jamie Angus, coustics and Psychoacoustics, 1698