Science1 publisher2 min readPublished
A musician who tunes to the electrical hum found his absolute pitch drifting in Norway
David Loberg Code teaches students to find concert A by listening to the 60 Hz hum of American wiring, and on Norway's 50 Hz grid he found his own pitch sense unreliable; RITMO's Arthur Jinyue Guo says there is no concrete proof yet.
The Scientist · Science desk
What happened
- David Loberg Code, a music professor from Michigan with a strong sense of absolute pitch, found that after coming to Norway to work his pitch judgments were lower than usual and suddenly unreliable.
- Code has taught aural skills for more than 30 years, and part of his method is having students sit still and listen to the 60 Hz hum of American appliances, which falls close to the pitch B1.
- North America's grid runs at 60 Hz and Europe's at 50 Hz, so the buzz of a ventilation system or a refrigerator is pitched differently on the two continents.
- Arthur Jinyue Guo of the RITMO centre gathered audio from kitchens, living rooms and railway stations worldwide alongside video of people moving through the same spaces, analysed with algorithms he wrote.
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Why it matters
- constraint A pitch or auditory-attention task replicated in Michigan and Oslo is run inside hums roughly three semitones apart, so the room's ambient frequency content is a variable that a decibel reading does not capture.
- exposure Any protocol that scores where a person stands or sits inherits the position of the air handler, because Guo's recordings caught people drifting toward the source while under instruction to hold still.
- decision Guo's argument puts a choice in front of designers who currently specify noise limits for lecture halls: where the ventilation opening goes, and what pitch it hums at, becomes part of the brief.
Move the hum from 60 Hz to 50 Hz and it falls by about 316 cents, a little over three semitones [18]. The ratio of the two frequencies is 1.2, and 1200 times the base-2 logarithm of 1.2 is 315.6. For a listener who locates concert A by referring to the wall, that is a large change in the reference. "The electrical hum in the room can thus be used as a reference pitch for finding 440 Hz," Code wrote in an email from the United States [7].
According to phys.org, Code arrived at the grid-frequency explanation himself, over time [19]. The observation behind it is a self-report from one musician who had also just changed continents. Guo is careful with it. "When the reference pitch is changed according to the AC frequency, it might also affect our ability to perceive absolute pitch," he said, and the researchers have not yet found concrete proof [9][10].
The broader claim rests on the recordings. "We saw that people unconsciously moved toward the part of the room the sound was coming from, even when they had been told to stand still," Guo said. "For example, it matters whether a ventilation system is in the middle of the ceiling, on one side of the room, or perhaps on both sides" [13]. The phys.org account does not report how many people were recorded, how far they moved, or how much Code's pitch judgments shifted [20]. Pattern-finding across rooms in different countries is also correlational: kitchens and railway stations differ in more than where the fan is.
Absolute pitch is rare, and Guo does not have it; he says similar subtleties of room ambiance affect everyone [15]. "We have seen that the rhythm of a room has a major effect on us. And by rhythm, we do not only mean a dance rhythm such as swing or cha-cha-cha," Guo said, and he counts the frequency of electricity among the rhythms people barely notice [14]. The claim that would carry weight beyond one professor's ear is the movement one, and it needs a condition with the sound switched off. "There seems to be more in this than what most of us are aware of," Guo said [17].
What to watch
- A within-subject test of Code on both grids, with the hum masked and unmasked, would separate grid frequency from everything else that changed when he moved.
- Publication of the movement data with participant counts, drift magnitudes and a sound-off condition.
- Whether auditory and attention labs start logging mains frequency and room hum spectra in their methods sections.