What Makes the Sound of Vuvuzelas so Annoying?

June 15, 2010— -- Love 'em or loathe 'em, the blaring plastic trumpets have become the hallmark of matches at the 2010 World Cup. We asked Trevor Cox, president of the UK Institute of Acoustics and an acoustic engineer at the University of Salford, UK, to explain their appeal – or otherwise

How do vuvuzelas make their sound?

The vuvuzela is like a straightened trumpet and is played by blowing a raspberry into the mouthpiece. The player's lips open and close about 235 times a second, sending puffs of air down the tube, which excite resonance of the air in the conical bore. A single vuvuzela played by a decent trumpeter is reminiscent of a hunting horn – but the sound is less pleasing when played by the average football fan, as the note is imperfect and fluctuates in frequency. It sounds more like an elephant trumpeting. This happens because the player does not keep the airflow and motion of the lips consistent.

But that din sounds nothing like a trumpet or an elephant.

When hundreds of the vuvuzelas are played together, you get the distinctive droning sound. People in the crowd are blowing the instrument at different times and with slightly varying frequencies. The sound waxes and wanes. The overall effect is rather like the sound of a swarm of insects.

Why are they so loud?

The loudness can be explained by the bore shape, which is roughly conical, and flares. 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.

A flared instrument has louder higher-frequency harmonics than a cylindrical one. The flared instrument is perceived as louder because the higher harmonics are at frequencies where our hearing is most sensitive. This is partly why the conical saxophone sounds louder than the cylindrical clarinet.

Since it produces 116 decibels at 1 metre, prolonged exposure to the vuvuzela poses a risk to hearing, according to a study by the Department of Communication Pathology at the University of Pretoria, South Africa. Listen to just one instrument for 7 to 22 seconds and you exceed typical permitted levels for noise at work. A whole crowd produces even higher levels, and measurements at a training match have shown temporary hearing loss among spectators.