Tuesday, July 13, 2010

Those Things Really Are Loud

Throughout the 2010 World Cup spectators heard the constant buzz of the vuvuzelas. Thought the match, the beehive sound from these horns was steady. This has lead to quite a bit of debate over the use of vuvuzelas during the matches. Some feel that the vuvuzelas add to the atmosphere of the matches while others complain that the persistent buzz noise is irritating, perhaps dangerous. One common objection is that they are simply to loud and take away from the enjoyment of the match. A recent study confirms this later criticism. In a preliminary report, acoustics experts from Texas and Florida report that the vuvuzelas used during soccer matches is extremely loud.

The studies were published as an article and series of letters in a 2010 issue of the South African Medical Journal. Noise levels and auditory tests were measured during a South African premier league match held in a FIFA designated training stadium. The sound recordings were made at the ear of the vuvuzela user, at the horn opening as well as 1 and 2 meters from the horn opening. A total of 10 subjects also participated in pre- and post-match hearing tests.

Noise exposure levels for the participants were well over 100db and often exceeded 140db. Subjects were also exposed to these noise levels for an average of 117 min before and during the match. As expected, noise levels were highest at the horn opening. However, the decibel level only decreased by about 13% at the ear of the user and 2m away from the end of the horn.

After the match, the subjects experienced slight hearing loss at some sound frequencies. The investigators suggested that the post-match changes were likely temporary but do emphasize that they could be indicative of long-term auditory problems.

To put this information into context, many regulatory agencies recommend ear protection for prolonged exposure to ~85 db. According to the South African National Standards for regulating noise at the worksite, workers should not be exposed to 90-95db for more than 1-2 hours. At 100db, workers should not be exposed for more that 15 min without ear protection. Based on these standards, noise from vuvuzela may contribute to long term hearing problems.

The investigators do not call for a ban on vuvuzelas. They acknowledge that they are an iconic symble of soccer culture in South Africa. They also note that they cannot pinpoint the exact contribution of the horns to overall crowd noise at a soccer match. In fact, there are a number of studies documenting excessive crowd noise at many different sporting events. Cheering fans, bands and other noise makers all contribute to the noise level. For example, in 2003, CBS recorded 130db on the sideline of a Louisiana State University football (American) game. And the authors are correct in that crowd noise is an important part of sports and can be a significant home field advantage. They do however suggest that more research is needed. Also, preventative measures such as public awareness and use of personal hearing protection may be warranted.

Yes, critics are correct. Vuvuzelas are loud, very loud. Perhaps some precautions should be taken to avoid long-term hearing problems. However, at this point, banning or restricting vuvuzelas will probably not impact crown noise. Football fans are very, very loud. This is an integral part of the game. Fans will likely find other ways to make noise - with or without the African horns.

References:

Swanepoel DW, Hall JW (2010) Football match spectator sound exposure and effect on hearing: A pretest-post-test study. South African Medical Journal, 100:239-242.

Swanepoel DW, Hall JW, Koekemoer D (2010) Vuvuzela – good for your team, bad for your ears. South African Medical Journal, 100: 99-100.

Swanepoel DW, Hall JW, Koekemoer D (2010) Vuvuzela sound measurements. South African Medical Journal, 100: 192.