WATERLOO - It's the harmony that hooks you.

Crystal-clear and perfectly pitched, voices in the Cedar Harmony chapter of Sweet Adelines balance and blend beautifully through their competition ballad, "If You Love Me, Really Love Me." After the final note fades away, the rehearsal room is dead silent for several moments, then erupts in laughter and clapping.

"If you don't like harmony, you won't stay. You fall in love with it and it makes you want to sing," says Carol Anhalt of Jesup, who joined the chapter in 1972.

Love for a capella singing - and lots of laughter - inspire these 35 dedicated women to show up each Monday night and spend several hours learning vocal techniques, singing and polishing choreography. Members are drawn from throughout the Cedar Valley, including the Waterloo-Cedar Falls metro area, Waverly, Shell Rock and Independence.

Director Sally Eggleston drives in from Cedar Rapids. She joined Sweet Adelines 45 years ago and is a competition judge and international faculty member.

The chapter is preparing for a public performance April 9 at Cedar Falls High School, and regional competition May 13-15 in Oshkosh, Wis. In previous years, the chorus has placed as high as third, but their eyes are on the big prize - winning the event and competing at the international level.

"Barbershop is a truly American form of music, like jazz and blues. Men sing 4-part barbershop harmony and Sweet Adelines sing 4-part barbershop-style harmony. This isn't 'Down by the Old Millstream' stuff; we're singing Broadway tunes, jazz, blues and contemporary music," Eggleston says.

Sweet Adelines International is celebrating its 60th anniversary year. The original chorus was formed in 1945 in Tulsa, Okla. "It's because women got tired of sitting at home on Monday nights while their husbands went off to sing in a barbershop chorus. And that's another difference - men bring their wives to conventions; women don't want their husbands along," Eggleston says, laughing.

Barbershop is four-part, unaccompanied, close-harmony singing, with melody in the second voice, called the "lead." Lead carries the melody; tenor is the harmony part sung above the lead; baritone covers the same range as lead and crosses lead notes; and bass is rich and mellow.

"I'd never sung in a chorus before. When I was in school, the chorus director told me I couldn't carry a tune," recalls Cedar Harmony chapter president Mary Kammeyer of Waverly. "Now I'm singing harmony," she says, smiling.

Marilynn Buxton never pictured herself as a singer or performer. "In school I was - now, don't anyone laugh at this! - very quiet." The outgoing Waverly woman joins in as her friends burst into laughter, shaking their heads "no."

Camaraderie adds a sense of joy and fun to each rehearsal. "It's a sisterhood. We describe ourselves as sisters because we are all that close," says assistant director Jo Wyatt of Shell Rock.

Carla Lown of Gilbertville agrees. "Many members have belonged for a long time, but it's not a closed sisterhood. When I joined in June 2003, everyone made me feel like I belonged."

With nearly 30,000 members worldwide, she could be embraced by sisters in dozens of countries and most of America's 50 states. There are more than 600 choruses and 1,200 registered quartets, making Sweet Adelines International one of the largest singing organizations for women. Cedar Harmony has two registered choruses, Fourever Rainbow and Plezant Company.

Members learn vocal production, choreography, stage production and costuming and receive music education. Training and certification programs are available in directing, arranging, judging and teaching.

"We're serious about our music. It's fun and you make friends, but it's work," explains Buxton. "My husband sings in the Shell Rock Swing Show every year and he said to me, 'I can't believe you do this every week of the year.' I said, 'We don't - we're off during Christmas.' We all love and want to be here."

"These women will sing at the drop of a hat - even on street corners," Eggleston says. She once directed more than 5,000 women at a mass sing in London's Hyde Park, perched on a statue of Prince Albert.

Wyatt recalls a mass sing 10 years ago in New Orleans as "one of the most amazing things I've ever done," and confesses Cedar Harmony is known for "spontaneous singing."

"Yeah, we're fun," Anhalt says, smiling. "We've been in restaurants and started to sing. Once we started to sing and someone came over to say Craig Johnson (former KWWL-TV meteorologist) was there and it was his birthday, so we sang Happy Birthday."

Another evening at Cedar Falls restaurant, members noticed a couple getting engaged. "We spontaneously sang for them. It gives me goosebumps even now to think about it. Her fiance said he thought he would be the one to give her a night to remember," Buxton recalls.

Melody Parker can be reached at 291-1429 or a melody.parker@wcfcourier.com