MUSIC : Voice of the People : For Grammy winner Johnny Mann, turning 75 amateur singers into a respectable chorus is a difficult but satisfying challenge.

Johnny Mann has performed as a backup vocalist to Frank Sinatra, Dean Martin, Johnny Mathis, Bing Crosby and Danny Kaye. His group, the Johnny Mann Singers, has captured two Grammys.

That was the easy part.

Now he must somehow blend the voices of 75 amateur singers into a respectable chorus. This time, he is working mostly with physicians and their families, many of whom can’t even read music.

“This is one thousand times more difficult,” said Mann, whose group, the UniHealth Americans Chorus, will perform two holiday concerts Sunday at Glendale High School. “For the professionals, you can give them the music and they’ll know it immediately. These people have to learn by rote. The hardest challenge is for them to memorize it.”

Yet Mann, still youthful at 64, finds plenty of satisfaction with his untrained group.

“They are doing these songs out of love,” said Mann, who is getting paid for his efforts. “That’s the secret to the whole thing.”

Mann’s favorite object of affection has always been his country. In the early 1970s, he was host of “Stand Up and Cheer,” a syndicated prime-time variety show that, even in the height of an anti-Establishment era, paid tribute each week to Uncle Sam. Mann doesn’t regret any of it.

“What inspired me was all the flag burning,” said Mann, of Chatsworth. “I got angry because I love this land.”

If anything, his love has grown, and he hopes to do a 1990s version of the patriotic show. So far, however, no networks or cable outlets seem interested.

“There’s no possible way it wouldn’t make it,” said Mann, who would be satisfied to produce the show. “It would be high energy. Even the ballads would be high energy.”

That has marked Mann’s career from the start. He has composed and arranged hundreds of radio and television commercials, and was the musical director of the original “Chipmunks” TV series. He also was in charge of music on ABC-TV’s “Joey Bishop Show” in the late 1960s.

“The Joey Bishop job was easy,” he said. “You got to work at 6 and would be done basically by 9. We had one advantage over (Johnny) Carson because all the Hollywood celebrities were in L. A. and Carson was in New York.”

His Johnny Mann Singers recorded 38 albums and captured two Grammy awards. They recorded two tunes first made popular by other groups--”Up, Up and Away,” from the Fifth Dimension, and “Mrs. Robinson,” from Simon and Garfunkel. Some of the Johnny Mann Singers continue to perform around the world, while others have retired.

Mann juggles a few ventures at once. He is almost finished with making a video on how to play piano. He complains that other videos have promised easy techniques without properly nurturing the student’s musical skills. Mann said the video, which has not yet found a distributor, will sell for $170.

“Most of the ones out there advertise themselves as miracle methods,” Mann said. “Our tape will have 20 lessons on there. It takes years to learn the piano.”

Meanwhile, he is preparing his choir for the holiday concert. In its performance, the group will sing an offbeat version of “The Twelve Days of Christmas” called “The Twelve Days After Christmas.” On the first day, the song, written by Frederick Silver, goes, “My true love and I had a fight, and so I chopped the pear tree and burned it just for spite.”

The chorus was formed last year when Mann approached CareAmerica Health Plans, a Chatsworth-based company that offers HMO insurance benefits to employer groups, about putting a chorus together.

“This seemed a little different from the usual thing,” said Arthur Southam, chief operating officer for CareAmerica. “There aren’t too many HMOs and hospital groups who do concerts. It was Mann’s idea, and it seemed like a good way to give something back to the community.”

With members from hospitals throughout the San Fernando Valley, the chorus held its first concert in February at Glendale High School. Mann hopes to stage two performances per year. The group rehearses Tuesday nights at Northridge Hospital Medical Center.

Where and When What: Holiday concert by the UniHealth Americans Chorus. Location: Glendale High School Auditorium, 223 Jackson St. Hours: 2 and 7:30 p.m. Sunday. Price: Free. Both performances are sold out, but there may be additional tickets at the door. Call: (800) 922-0000.