Seventy-five years ago a seminal article described how perceived musical pitch for two cases—pure tones and harmonically rich ones—depends not only on the actual pitch but also on intensity. 1 Many readers, including Ralph Leighton (Physics Today, June 2010, page 8), are probably not aware of those surprising psychological phenomena, which are also little known to musicians and music lovers in general. Richard Feynman’s close friend, amanuensis, and musical duet partner, Leighton offered as one example of Feynman’s tone-deafness his misinterpretation of notes played louder as being higher in pitch. Most musicians obviously learn to correct themselves for those effects, or no music, solo or ensemble, would ever sound in tune.

1.
H.
Fletcher
,
Bell Lab. Rec.
13
(
5
),
130
(January
1935
).