Vuvuzelas – crossing the pain threshold

Today is the last day for this time that the World Cup is being brought to your screens, so withdrawal symptoms are merely pending.

This also means that vuvuzelas will no longer be heard on a daily basis. The glorified, but less melodic, kazoos have made footballers snarky, live audience grimace in pain and spectators reach for insecticide. All of these may occur naturally during any other World Cup, but the lepatata (the offender’s Tswana name) has been firmly singled out as a scapegoat.

The stadium horn is, typically, approximately 65 centimetres long, and  emits a b-flat below middle C; if heard at one metre from the horn opening, the listener gets knocked by sound pressure mearusing 120 decibels (dB), which is just about the threshold of pain for most humans. Therefore, prolonged exposure at close range will lead to hearing loss, for unprotected ears.

To provide an idea of exactly what is being contended with, see this chart below, featuring the measurements of some common, or at least more definitive, sounds.

Decibel Chart
Bear in mind, also, that if you reduce the sound pressure from 20 dB to 10dB, you cut the sound level in half. (Image from West General Acoustics.)

If exposed to high sound pressures for prolonged time, sensitive structures in the inner ear, called hair cells, are damaged. These cells convert sound energy into electrical signals that are then passed onto the brain. Once damaged, these cells cannot repair themselves, thus resulting in permanent, noise-induced hearing loss.

Have a look here for more details.

Personally, I have given in, and installed a vuvuzela application on my mobile phone; however, I can control the sound level on this one, so we are alright!


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