Ville Pulkki has been perplexed as to why shouting upwind seems to be so challenging for years. The experience is widespread enough to have inspired an expression about not being understood. Aalto University professor Pulkki, who specialises in acoustics, desired a scientific explanation for the event, but there wasn’t one.
In a recent study that was published in Scientific Reports, Pulkki’s research team demonstrated that our perception of this circumstance is incorrect based on common sense. Screaming into the wind doesn’t make it harder to be heard; it just makes it more difficult.
In fact, sound propagates better in the first 100 metres upwind, as acousticians have long known. Many people have heard how a siren gets louder as it gets closer and quieter as it gets farther away. The Doppler effect, in which a sound changes frequency as it moves, is the mechanism behind this.
It was proven by Pulkki’s earlier studies that wind has no effect on the way speech is emitted, thus shouting into the wind shouldn’t be challenging. Rapolas Daugintis, one of his master’s pupils, was tasked with determining whether the phenomenon was caused by the way we hear. Timo Lähivaara, a senior researcher at the University of Eastern Finland, contributed acoustic and flow field simulations, and Daugintis performed measurements and simulations to test the theory.
Their findings were unexpected but straightforward: yelling upwind makes it more difficult for people to hear yourself.
“When someone shouts upwind, their ears are situated downwind from their mouth, which means that their ears receive less sound—it’s harder from them to hear their shout than when there’s no wind,” claims Pulkki.
The same situation occurs when someone is moving swiftly even when there is no wind present, such as when riding. Even in still air, a person riding a bike creates a breeze around their head, making it difficult for them to hear their own voice, which leads them to shout.
Therefore, use caution when shouting upwind since even if you can’t hear what you’re saying, others might. People who work with sound, like musicians, will find this material to be especially helpful.
“My musician friend told me that when they have to sing on a sailboat, they always sit with their back against the wind in order to not strain their voice. The same phenomenon is at play here: because it’s harder for my friend to hear themself when singing upwind, it makes them unknowingly sing louder than usual,” says Pulkki.
