Broadway joins age of high-tech sound. Don't look for the orchestra at `Starlight Express' - it's on the fourth floor

When ``My Fair Lady'' opened on Broadway 31 years ago, it was considered revolutionary because it had six foot-mikes. Today, a popular musical like ``Cats'' has 35 mikes, 35 speakers, taped voices enhancing the sound, synthesizers, and orchestra members who have never seen the show because they're backstage.

Broadway is now at the peak of a technical revolution that has changed live theater. This new high technology means that the audience can hear from every seat in the house. But it also means that unamplified acoustic sound is gone from the Broadway musical.

``You can't hear singing from their mouths, even if you're sitting in Row D. You hear it from a speaker,'' says Otts Munderloh, one of Broadway's leading sound designers. Shows now ``rise and fall on how good your sound operator is,'' Mr. Munderloh says. ``Everything must be done at the console.''

Each orchestra member has a mike now; the stage has foot mikes; and singers are individually wearing wireless mikes. In addition, the sound engineer mixes offstage singers, tape, and sound effects through the sound board at the back of the theater.

Even members of the Broadway community don't realize that in three plays - ``Cats,'' ``Starlight Express,'' and ``Chorus Line'' - there is a television camera mounted on the balcony, and the conductor watches the stage on a video monitor. ``I've had many people say to me, `There's no orchestra. It's on tape,''' says Jess Heimlich, sound engineer for ``Cats.'' In reality, the orchestra is playing live, but it isn't in view. It's all the way up on the fourth floor at ``Starlight Express,'' and behind the stage at ``Cats.'' At ``A Chorus Line,'' it's in the pit, but the pit is covered over with black material.

These same three musicals also use ``pit singers,'' or offstage voices, to sing live and enhance the sound. More surprising, though, is that singers will lip-sync to tapes of themselves during live shows. A taped voice is used for the narration of ``Starlight Express,'' allowing Braden Danner to appear live in ``Les Mis'erables'' and on tape at ``Starlight'' simultaneously.

All of these electronic tricks are used for one main purpose: to make sure the audience can hear. For Bernard Jacobs, president of the Shubert Organization, ``The important question is: What is the best sound you can get? And if you can get better sound, why burden the audience with something less when you can give them something more?''

The audience is growing sophisticated about sound, Mr. Jacobs says. People now own hi-fi systems and CD players that sound better than theatrical acoustics. So it's a question of meeting the demand.

``In the right hands, technology enhances the sound,'' says Paul Gemignani, musical director of many Stephen Sondheim shows, including this season's ``Into the Woods.'' But, he says, amplification encourages the audience to be lazy. ``People don't know how to listen anymore,'' Gemignani says. ``It's not in people's hearing capacity. It has to be spoon-fed to them.''

This cheats the audience out of experiencing live sound. ``The danger is that the difference between Broadway and TV or movies gets smaller,'' says Fred Chapin, who plays guitar and banjo in ``Me and My Girl.'' ``Every element that they make more remote [from audience] brings them closer to TV or MTV.''

Chapin says this also robs the musicians of a special experience. Having played with the backstage ``Cats'' orchestra, Chapin says, ``There's more separation between the orchestra, cast, stagehands, and technicians. What you were doing seemed so isolated.''

Keeping the sound of a musical going is so complicated, it takes two technicians working together. One mixes the show through the soundboard, and the other is backstage to fix equipment, which can break at any time. An hour before ``Cats'' starts, technicians check the sound system and all 14 body mikes, which look like small walkie-talkies. The antennas on the body mikes can snap very easily, and perspiration can short out the mike, knocking out the sound.

If too many theaters across the street or down the alley use body mikes, their radio signals cancel each other out. When video cameras stop working, or microphones break, little can be done until the end of the act.

``La Trag'edie de Carmen'' in 1984 was the only recent exception to the extensive use of mikes. There wasn't one piece of sound equipment used on either the singers or musicians, according to Alexander Cohen, the producer.

``We had not one single complaint of sound, which is so extraordinary as to be almost unbelievable,'' Mr. Cohen says. ``Under the proper circumstances, you can avoid amplification if you want to.''

Such proper circumstances don't arise often, so sound designers and engineers are now refining sound systems.

``The aim is not to make it sound amplified. We're using more and more equipment, but we're trying to make it sound more natural,'' says Michael Allen, sound engineer of ``A Chorus Line.''

No one is sure about the future of high-tech on Broadway. Designer Munderloh predicts that ``10 years from now, there may be a reactionary backlash.'' Acoustic sound may return. Paul Gemignani agrees that ``we may reach a saturation point and go backward.''

Broadway doesn't exist in a vacuum. Today, television is in stereo; movie theaters have huge sound systems; and even the New York City Opera is using microphones to amplify dialogue.

``There's been a change in everything,'' observes Bernard Jacobs. ``Why should Broadway be any different?''