Sixty blocks and an entire universe separate the Choir Academy of Harlem from the illustrious Lincoln Center concert hall where the girls will make their debut on Nov. 23. But the voices that float through the modest East Harlem rehearsal room are nothing short of heavenly–silvery, melodic and majestic. The Harlem boys, with their prepubescent voices, actually sound like young girls. The girls sound like angels.

The Girls Choir was started in 1979, then disbanded due to lack of funding. ““I needed to hire somebody to focus strictly on the girls,’’ says Walter J. Turnbull, founder of both choirs. ““But I could barely afford an accompanist for one rehearsal, let alone two.’’ Turnbull reassembled the Girls Choir in 1989, but money was still an issue. Six months ago a Revlon executive living in Harlem heard of the choir’s struggle and persuaded his company to sign on as the girls’ official sponsor. (The boys are sponsored by Gillette.) ““The girls have a fighting chance now,’’ says Turnbull.

For many of the girls, just the chance to attend the Choir Academy is a big break. The public school, home of both the Boys and Girls choirs, is small by city standards. With only 550 students, it’s a place where students get personal attention and topnotch academics. Last year 100 percent of the graduating class went on to college. ““I get up every morning at 5:30 to be here, and then I stay after school to rehearse,’’ says Bronx native Courtney Davis, 15. Tia Bonner, 14, says, ““In my old school, my teachers didn’t care. Now that I’m here, my mother is so happy. She makes me go to rehearsal, even if I’m sick.''

The girls hope to launch a national tour in 1998, and eventually work up to the 125 concerts the boys perform every year. But they say they sing as much for each other as for any audience. ““Music is a language,’’ says Guzman as she puts an affectionate arm around a friend. ““That’s how we express ourselves as sisters. Because that’s how we think of ourselves–as sisters.’’ Spoken like a true angel.