Perhaps you recall the vuvuzela, the plastic horn that provided the buzzy soundtrack for the 2010 World Cup? Well, next year’s World Cup in Brazil has a new signature instrument, and thankfully, scientists have already determined that it won’t sound like a chorus of flatulent demons when blown en masse.
Brazilian musician Carlinhos Brown designed a new maraca-like instrument for the soccer tournament that he’s dubbed the “caxirola.” This is a new take on an African and South American instrument called the caxixi, which is traditionally made from a tightly woven basket lined with a flat bottom made from dried gourd, and filled with seeds. The noise comes from shaking the caxixi such that the seeds strike that flat bottom.
“The caxirola respects auditory boundaries,” Brown told the Brazilian news portal G1 in April. “It reproduces the sounds of nature, of the sea, so we work with the best engineers to make sure the sound will be pleasing and nice.”
Some modern caxixis are made with metal, but the caxirola is made with "green and sustainable" plastic, Brown says. “We have to be responsible.”
But is the caxirola really a quieter, gentler noisemaker than the vuvuzela? Talita Pozzer and Stephan Paul, researchers at Brazil’s Federal University of Santa Maria, decided to investigate. They asked 22 people who’d never seen a caxirola before to play it, then recorded the noise the instrument made.
They found that the caxirola is slightly louder if you shake it along its longer axis, but either way, the instrument isn’t much louder than normal conversation. Importantly, the caxirola’s rattle is also 45 decibels lower than the vuvuzela, which corresponds to a sound energy of about 1/30,000th that of the honking plastic horn. Pozzer and Paul are scheduled to present their findings next week at the annual meeting of the Acoustic Society of America in San Francisco.
The researchers’ next step will be to measure the caxirola’s sound power levels. Unlike sound pressure levels, an instrument’s sound power is consistent across distances and surroundings. Then Pozzer and Paul can use a computer program to simulate what thousands upon thousands of caxirolas would sound like inside a soccer stadium.
It’s still uncertain whether the caxirola will actually be making a big splash at next year’s World Cup. Some soccer fans have found that the handheld instruments are handy projectiles, and a disgruntled crowd hurled the instruments to the pitch earlier this year, interrupting a match between the Portuguese soccer club Vitoria F.C. and Brazilian club Bahia. In May, Brazilian officials banned the caxirola from the Confederations Cup – a dry run of sorts for the World Cup -- this past June, and may keep the ban in place for the main event in 2014.
So, while the vuvuzela might have exposed people to riskily high levels of sound and also had the potential to spray germs throughout a packed crowd, at least it wasn’t heavy enough to be thrown at another fan’s head.
Roxanne has liked science ever since she started watching "Bill Nye the Science Guy" on Saturday mornings over a bowl of sucrotic O's. She especially likes writing about...