Visitors to Madrid have much to marvel over: splendid architecture, sizzling nightlife, great food and people who scream at each other.

The Spanish penchant for loudness -- loud mouths, loud televisions and myriad other outlets -- kicks in early and stays. Listen to 4-year-olds at play, or men talking soccer over a pre-luncheon vermouth. Until now, exploding decibels were okay.

Now the city government, itself blamed for much of the racket in this city of 3 million and facing elections next spring, has launched a campaign to encourage quiet.

"SSSHHH. Control your noise," as the campaign is known, started Sept. 13 and is expected to last through the end of next year.

Fingers raised to their lips, a dozen blue-clad mimes have begun to roam bustling streets with a choreographed skit urging children and adults to speak softly. Two city landmarks, the statues of Cibeles and Neptune, appear in posters with the same hushed pose.

Local officials said a planned Web site will offer other hints for making Madrid acoustically gentler: Wear slippers around the house, refrain from slamming doors and don't remodel your apartment at night.

Placido Perera, head of noise-control at the city's environmental protection unit, insisted that reminding grown-ups not to yell isn't insulting.

"There are a lot of things that are just common sense, but which people don't embrace as such," he said.

Perera, whose first name means placid, said that after 30 years of studying noise he has concluded Madrid is indeed loud, although probably no worse than other major European cities.

Of the 23 spots in Madrid that are monitored nonstop, the noisiest -- Paseo de Recoletos, a downtown thoroughfare -- peaks at about 71 decibels, he said. Noise becomes potentially hazardous to people's hearing at about 80-85 decibels.

What sets Madrid apart, Perera said, is that residents whining about noise often have themselves to blame. The campaign aims to curb behaviors such as screaming, honking a split second after a traffic light turns green and carousing vociferously late at night along narrow streets.

"These are very Spanish behaviors," he said.

A busy Spanish coffee shop at breakfast time serves up another example of the national din: Diners struggle to be heard as plates rattle, the television blares and slot machines bleep and whir.

Why all the yelling in the first place?

Tongue planted firmly in cheek, the late Spanish poet Leon Felipe addressed the issue in 1942 in an essay entitled "Why Spaniards Talk So Loud." He said one reason may be that they descend from Rodrigo de Triana, Christopher Columbus's lookout who spotted land and simply did his job. "Tierra!" he cried.

Sociologist Alberto Moncada says the penchant for noise may signal an attempt to project power.

"We start screaming from the time we are in day care," said Moncada, who lives above a day care center and reports epic shouting matches. "We are not taught not to scream."

Among adults, he added: "There is a sort of notion that talking loud is a show of personality. What I see is that when people speak slowly and in a soft voice, it's as if they feel humiliated."

Perera said Spain is an example of a Mediterranean culture in which nice weather leads people to spend lots of time outdoors, on the street, where louder discourse is a necessity.

The problem is they take those decibels back home with them, or to the office.

In Madrid, not all the noise is human. People are so weary of seemingly endless road work and construction under Mayor Jose Maria Alvarez del Manzano -- and the drone of jackhammers and bulldozers -- that, according to one joke, Madrid will be a great city when it's finished.

In one downtown district, people have hung banners over their balconies proclaiming themselves victims of acoustic contamination.

But Perera denied suggestions that local officials are trying to shift blame for the city's noise problems to the people who put up with them. "We're not passing the buck to anyone," he said.

Mimes roam the streets of Madrid, encouraging Spaniards to keep it down as part of a citywide campaign to cut down on noise by changing common behaviors such as screaming.