What’s music to a restaurateur’s ears is an earache for his neighbors.

There are a million enchiladas in the big city, a fact that is not lost on Juan Guerrero.

So a year ago, when the restaurateur opened his Old Mexico eatery in Redondo Beach, he cannily hedged his bet.

Music, Guerrero and his partner figured, would be the key to their restaurant’s success: mariachi music during the Sunday dinner hour.

Little did Guerrero suspect that those jaunty trumpets, bright guitars and lilting violins would land him in the proverbial soup. This week, the City Council told him he would have to tone down the music or face revocation of his entertainment permit.

The problem, according to Sheila Schoettger, the city’s harbor director, is that trumpet music tends to carry. And the residents of the condominiums and apartments near the International Boardwalk, where Old Mexico is situated, complained that the revelry was carrying on far into the night.

The entertainment that began on Sunday afternoon was still going strong at 10 p.m., and 11 p.m. and after midnight and on through into the wee hours of Monday morning, Schoettger said. And the perky sounds of the house musicians were driving bleary-eyed neighbors from their beds.

“I try to tell my partner, stop the music. But he was happy! What could I do?” Guerrero sighed.

The music, he added, is his bread and butter.

“Without it,” he said, “no way I can pay the bills.”

The council was understanding.

“We all love mariachi music,” said Councilwoman Kay Horrell, “but those people down there don’t enjoy it in their bedrooms at 12 and 1 o’clock in the morning.”

Whereupon Guerrero was warned that from now on the trumpeting would have to stop at 10 p.m., and take place only with his cafe’s doors and windows closed.