By Michaela Howard BBC Birmingham

During the World Cup final in Japan chances are that when the referee blows the final whistle supporters across the globe will hear the loudest sound ever to come out of central England.

J Hudson & Co have produced whistles in a small factory in the jewellery quarter of Birmingham for the past 132 years - many under the brand name, Acme Whistles.

Today they produce the preferred whistle of this year's World Cup, but not the official referee's tool - that privilege would have cost them �100,000.

Simon Topman, J Hudson & Co managing director, said their product was specially designed because of the nature of the modern stadium.

"You have these huge stadiums, bowl shaped, with a slightly overhanging roof and this tends to focus crowd noise," he said.

"Not only have you got the people chanting and shouting, but these days if the Brazilians are playing you've got a mass band, you've almost got a carnival going on in the stands and there's the poor old referee in the middle with nothing but his whistle to control the game," he added.

Whistling technique

Ex-premiership referee turned assessor, Roger Millford, said effective use of the whistle is all down to technique.

The designs of new stadiums tend to focus crowd noise

"Most players, the professionals, understand that once the whistle goes at the start of the game they pick up the tune or the tone of that whistle," he said.

"We have got the saying in refereeing that 'you can play a tune on the whistle', what we mean by that is you can talk via the whistle as against verbal commands. If it's a goal kick - a slight little peep on the whistle.... a free kick - a bit heavier on the whistle."

With crowd noise rising 50% over the past 20 years it was important for Hudson's to create a whistle that would cut through the overwhelming spectator noise.

Yellow card

Ex-England International, Chris Waddle says it is so easy to get into trouble with the referee simply because players can't hear the whistle.

"If you are in an attacking area and you might be committing defenders and you are going towards the goal and the crowd obviously get excited and very vocal, so somebody might be offside when you've passed it to your colleague and he doesn't hear it because the atmosphere's loud and everybody stops apart from him," he said.

"He ends up shooting the ball into the goal or just missing and the referee brings out the yellow card for saying he has kicked the ball away, wasting time."

Latest technology

A considerable amount of scientific research has gone into making this whistle with the help of Birmingham University's acoustic department.

It has no pea, is made from moulded plastic and acts on wave interference creating a trill rather than a traditional whistle.

Since the firm's birth in the 1860's with the introduction of the London Metropolitan Police whistle the company has made around 500 million whistles.

In the 1930's during the firm's peak it produced 300 different models.

Nowadays they only have 83 varieties from a wide selection of sports such as the rugby referee whistle, the basketball referee's whistle, the duck or a pigeon call, or even ones used on lifejackets.

In this year's championship every ref will be given a Tornado and Simon Topman hopes they will be used to keep the players in check.

"The referees have a choice, it is not compulsory that they use our whistle," he said.

"They can choose whatever whistle they wish and some of them will no doubt choose something else but we are very confident there is going to be a lot of our whistles on display this summer."