The straightened trumpet popular at this year’s World Cup have been resonating through stands and fans. The plastic instruments are played by blowing a raspberry into the mouthpiece, producing a sound that has been compared to an elephant trumpeting. When vuvuzelas are played en masse, they give off a droning sound which can excite fans and players — or drive them crazy. Recently, asked an acoustic engineer to explain why.

When a lone vuvuzela is played by an expert, it is said to sound like a hunting horn. But at the World Cup, it’s being blown by crowds of thousands who make it sound more like a swarm of bugs, possibly a swarm of killer bugs. Experts say this is because the horn is being played by amateurs who do not keep the air flow and the motion of their lips consistent. The instrument is also being played by thousands of people at once. asked Trevor Cox, president of the UK Institute of Acoustics and an acoustic engineer at the University of Salford, to explain why the vuvuzelas sound so loud and dissonant. As Cox explains, “the loudness can be explained by the conical and flared shape of the horn. As well as creating sound at a frequency of 235 hertz, the instrument generates harmonics — sound at multiples of the fundamental frequency. We have measured strong harmonics at 470, 700, 940, 1171, 1400 and 1630 hertz.”

Further, it seems that prolonged exposure to the horns can result in hearing loss. A study by the Department of Communication Pathology at the University of Pretoria, South Africa, reveals that the horn produces 116 decibels at 1 meter. This is enough to harm the human ear. As reports, if you listen to just one instrument for 7 to 22 seconds, you exceed typical permitted levels for noise at work. And the droning sound adds to the annoyance factor. Cox points out that droning sounds are harder to ignore and more alerting than broadband noises.

So is there anything to be done to curb the damage of droning vuvuzelas? Cox says the sound gives the games atmosphere, so it’s not like spectators or commentators will ever want to ban the vuvuzelas. As he advises, “you might just have to try and accept the sound as being part of the background. Lack of control over a noise source has been shown to increase its perceived annoyance. So your best bet might be to crack open another beer and try your best to enjoy the atmosphere.” Maybe with a couple of ear plugs in hand, just for backup.

For further reading:

What makes the sound of the vuvuzelas so annoying?

Experts sound off on vuvuzelas
The blaring plastic trumpets produce a signature noise for the 2010 World Cup. Here's why they're driving some people up the wall.