To take the measurements, a car was used to move a model of the steering gear, generating winds that bypassed it. Credit: Aalto University
For many years, Phil Polkey has been wondering why it’s so hard to shout upwind. The sensation is common enough to find its way into a term about incomprehensibility. But Pulkki, a professor of acoustics at Aalto University, wanted a scientific explanation for the phenomenon — and there was no one.
In a new study published in Scientific reportsPulkki’s research team showed that our common sense understanding of this situation is wrong. It’s not hard to scream into the wind. It’s hard to hear yourself.
In fact, acousticians have long known that sound carries best in the first 100 meters upwind. Many people have noticed that the siren sounds louder as it approaches and quieter as it moves away. The mechanisms behind this are similar to the Doppler effect, where sound changes frequency as it moves.
Polki’s previous research confirmed that wind does not affect the pattern of speech emission, so there is no reason why shouting into the wind should be difficult. So he asked one of his master’s students, Rabolas Dugentis, to study whether this phenomenon was caused by the way we hear. Daugintis performed measurements and simulations to test the idea, and senior researcher Timo Lähivaara of the University of Eastern Finland contributed acoustic and field simulations.
Their results were surprising, but simple: It’s hard for people to hear themselves when shouting upwind.
“When someone is screaming upwind, their ears are located downwind from their mouth, which means their ears are receiving less sound—it’s harder for them to hear their screams from when there’s no wind,” says Polkey.
The same thing happens when someone is moving quickly even when there’s no wind blowing – if you’re riding a bike, for example. When a person cycles, their movement generates wind around their head even in still air, and they end up screaming because they can’t hear themselves well.
So be careful what you shout upwind, others may well hear you, even if you don’t. This information is especially useful for people who work with sound, such as musicians.
“My musician friend told me that when they have to sing on a sailboat, they always sit with their back to the wind so as not to strain their voice. The same phenomenon is at work here: because it’s hard for my friend to hear their voice when singing upwind, it makes them sing louder than usual without Meant,” says Polky.
more information:
Ville Pulkki et al, the perceived difficulty of shouting downwind is a misconception explained by the thermal attenuation effect, Scientific reports (2023). DOI: 10.1038/s41598-023-32306-z
the quote: It’s Not As Hard As You Think To Shout Upwind, Study Shows (2023, April 24) Retrieved April 24, 2023 from https://phys.org/news/2023-04-difficult-shout-upwind.html
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