Hark -- was that a flat note? Who cares!

It doesn’t take much coaxing to get Jack Williams to perform. Just ask his wife, Winifred, or any of the other regulars at the Saturday night singalongs at Marcello’s restaurant in North Hollywood.

Williams, an affable nonpracticing lawyer and La Canada resident, has a rich, booming voice he describes as bass-baritone. And, he confesses, “If we are in a strange place, I ask the people around me if they mind if I sing a song. I tell them that it’s our anniversary, and my wife wants me to sing her a song. They love that.”

The Williamses celebrate their anniversary with astonishing frequency. “Gotta have a ploy,” he admits.

There are a lot of people out there like Williams -- amateur singers in search of a microphone. And each year, when the holiday season rolls around, many such musical egos get their annual chance at the spotlight. Williams sings all year, but he notes: “I think everybody’s voice comes out at Christmastime.”

Some holiday singers may choose restaurant or nightclub singalongs tailored to the season; some chime in at private parties; and some may simply sidle up to a troupe of professional carolers at a shopping mall and join in uninvited.

Others prefer the more formal setting of a singalong in a house of worship or concert hall. Many organizations, including the Los Angeles Master Chorale, a resident company of the Los Angeles Music Center, offer an annual “Messiah” singalong -- for those who prefer the challenge of Handel’s “Hallelujah!” Chorus to “Silent Night” or “Grandma Got Run Over by a Reindeer.”

Linda Krantz, manager of a La Canada medical office, sings in the choir at Trinity Lutheran Church in Pasadena but says the experience doesn’t compare with being part of the Master Chorale event, in which she’s sung on and off since 1981. Last year, Krantz, who is a member of the board of Pasadena Symphony, missed the singalong because she was attending a performance by the organization’s Youth Symphony. This year, she skipped the youth orchestra concert to attend the singalong at Walt Disney Concert Hall.

“It’s just magical, particularly as a nonprofessional, to have the opportunity to sing a piece of the magnitude of Handel’s ‘Messiah,’ ” says Krantz. “To sing that with 2,000 voices, many of which are obviously professional -- and some of them not, obviously -- is just so exciting. It’s part of what marks Christmas for me.”

Orange County accountant Sue Bell has served as a financial consultant to the Master Chorale but acknowledges that balancing the books for a choral group doesn’t mean she can sing. “My children tell me, ‘Just mouth the words, Mom.’ They didn’t get lullabies from me, they got lullabies on tape,” she says. Her voice, she adds, seems to wander from soprano to alto at will.

Yet despite their childhood trauma, the kids are now well-adjusted young adults -- and Bell is still singing. This year, she attended a concert and singalong by college choristers from Long Beach.

“At Christmastime, I absolutely do enjoy that. To be in the audience for a ‘Messiah’ singalong, or any singalong really, there are going to be lousy voices, but there are always going to be a few wonderful voices, and it makes you feel like such a part of it,” she says.

“It’s like water to my soul, it’s so beautiful” is how Jan Ewell describes the experience. The journalism and English teacher at Rancho Alamitos High School in Garden Grove says, “We’re so pressured most of the time, it’s wonderful to do something just for the beauty of it.”

Ed and Jayne Newhall of Rolling Hills Estates, a retired engineer and psychiatric social worker, respectively, also sang at Disney Hall this year and have participated in singalongs at El Camino College and elsewhere.

“The main reason we do it is, it’s just beautiful music, and it’s much better participating in than just sitting and watching,” Ed Newhall says. “My mother used to play the violin and the piano, and she would say, ‘String quartets are not that great to listen to, but they are wonderful for those who are participating,’ and I guess it sort of applies to the ‘Messiah.’ ”

Holly Addy is Saturday night pianist at Marcello’s, where Williams sings (she also does private parties and funerals). Each year, she brings sheet music decorated with ribbons and insists that restaurant patrons get into the Christmas spirit by singing carols “whether they like it or not.”

“There’s safety in numbers,” Addy says. “It’s like the parking lot syndrome, where you pull in and there’s nobody around you, and then two other cars park right next to you rather than using the rest of the lot.

“I do a real cheesy thing with ‘Jingle Bells’: They have to get their keys out and laugh real loud. It’s embarrassing even to tell it,” Addy continues. “People you don’t expect will just shake the bejesus out of their car keys. The Jewish people are the ones who sing the best and the loudest, and they bring their jingle bells and go crazy.

“I don’t know what it is,” muses Addy. “There’s something about the holiday songs that gets everybody into a different place than they ordinarily would be.”