A British acoustic expert has opined that the conical shape of the popular Vuvuzela, which is making its presence felt at this year’s FIFA World Cup in South Africa, is primarily responsible for its ear-splitting loudness.As well as creating sound at a frequency of 235 hertz, the instrument generates harmonics – sound at multiples of the fundamental frequency. 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 clarine.
Since it produces 116 decibels at one metre, prolonged exposure to the Vuvuzela poses a risk to hearing,
It’s shaped like a bugle or trumpet (I used to play the bugle) and I think this shape is designed to project the sound. I think the reason it seems so prominent is that the tone is right in the middle of your hearing range, so it’s difficult to ignore like some other sounds. I’m not an expert on acoustics though!
All trumpet type instrument act as a resonator, that is they are just the right size and shape to allow the sound waves you make with your mouth and lips to be in effect amplified. Its a bit like using an upturned traffic cone as a megaphone, or even some paper rolled in to the shape of a funnel. It directs the sound waves in a single direction making the noise in that direction much more focussed and louder.
The vuvuzela can really only make a single note whereas a trumpet is designed to allow the player to make many notes by using the keys. A bugle is just a curled up vuvuzela but its design and the players skill can get a range of notes out of it.
The fact that they are made of plastic (not brass) means they sound pretty awful too. If you cut them to different lengths they could make different notes and someone has done this and recorded some songs.