Quiet!

Why did someone who has visited Brazil and always been fascinated by its dynamic traditional culture walk out midway through a performance last weekend by the Viver Brasil Dance Company at the John Anson Ford Amphitheatre? Because the amplification of the company’s live music proved so extreme and ruinous that it created an impenetrable screen, nullifying the dancing.

Yes, virtually the entire entertainment spectrum -- pop music, movies, Broadway musicals and even opera -- has become increasingly enslaved to manipulative and sometimes apocalyptic sound engineering, and we’ve all learned to cope. But in Hollywood on Saturday, the hills were alive with the sound of reverb, and this listener reached his limit.

Ultimately, at the painful volume level enforced through Act 1 of “Bahia: Land of Magic,” it didn’t matter if vocalist Vania Amaral hit the right notes or if the percussion ensemble played skillfully. It mattered if they stopped. And as each new sequence in the first hour became something to be endured rather than enjoyed, the show seemed pointless for even a reviewer on assignment to write about.

As a critic, you’re supposed to identify and highlight the most significant achievement of an event, and sometimes that responsibility involves acknowledging that music artistically outweighs dancing -- as in a collaboration between cellist Yo-Yo Ma and choreographer Mark Morris at the Irvine Barclay Theatre in 1999. Conversely, critics and audiences sit through a lot of awful music in their hunt for great ballet performances. But what happens when sheer volume obliterates not only the dancing but also nearly all the qualities of the music itself?

Viver Brasil’s sonic boom is all too typical. Flamenco at the tiny Fountain Theatre in Hollywood, for instance, often is so over-amplified that you can feel the music vibrating through the seats and floor. Moreover, such popular Broadway-style companies as Riverdance are so wedded to high-volume sound mixes that they have resorted to prerecording the dancers’ tap sounds. Yes, the dancers do the steps, but how else could we hear them?

Because Viver Brasil attracts a large, enthusiastic audience, the company will have plenty of opportunities to present its repertory on local stages -- and to consider whether its technology is appropriate to its vision of Brazilian traditions. Reportedly, its technical director attempted to get the volume reduced Saturday some 15 minutes into Act 1 but succeeded only with Act 2. So what happened may have been an accident or a misinterpretation of the company’s intentions by a Ford sound engineer.

Either way, the evening illustrated how drastically amplification in the theater has changed from its original mission: to allow audiences to hear what would otherwise be inaudible and to make it possible for the artists onstage to monitor themselves and one another.

Today, other priorities determine the sound levels we encounter. For example, midway through Viver Brasil’s first act, a call-and-response passage briefly featured the unamplified singing of six dancers onstage. Surprise: They could be heard perfectly unplugged. But hearing isn’t believing anymore, and the need to make the company’s music seem not merely natural but oh, wow, awesome left everyone else in Act 1 singing and playing into microphones -- even a drum ensemble powerful enough to waken the ancient Orixa gods.

In our culture, many people live with music every waking moment, but it’s rarely live or acoustic. So when we do encounter live music, we expect it to match what we accept as the norm: the presence, detail and intensity of recordings. We’ve come to prefer processed music to the real thing.

Acoustical engineering and sound design attempt to deliver that illusory norm in the theater through everything from the architecture of our newest performance centers to elaborate isolation techniques that keep each singer or instrumentalist inside a sonic spotlight and then carefully mix them when they perform together.

As Times music critic Mark Swed reported this year, the New York State Theater at Lincoln Center, home of the New York City Opera, is one of a number of performing arts centers that recently had installed hundreds of small loudspeakers all over the hall to give, in his words, “operatic voices clarity and presence. But many listeners hear telltale loudspeaker ‘coloration’ in the hall, and they don’t like it.” They also didn’t like the body microphones and amplification in Baz Luhrmann’s Broadway staging of Puccini’s opera “La Boheme,” coming to the Ahmanson in January.

“The amplification of ‘La Boheme’ at the Broadway Theater is far more subtle than the blasting sound systems so common at musicals these days,” Anthony Tommasini wrote in the New York Times. “Still, the actual voices are flattened into an amplified wall of sound, and the spatial element of operatic singing, with voices coming from different locations on the stage, is completely undermined.”

Ironically, at exactly the time when concert dance, Broadway and even opera seem to be amping up, that old devil rock ‘n’ roll may be heading in the opposite direction. So says Nic Adler, owner of the Roxy on the Sunset Strip and a longtime observer of the pop scene. “During the 1980s and early ‘90s, it was about turning it up as much as possible,” he said in an interview this week. “But now the emphasis seems to be on clarity. People are into hearing more of the music, and I rarely find managers of bands who just want it loud.”

Motion pictures get more criticism for excessive decibels than any other art, but Ioan Allen , vice president of Dolby Laboratories, says “a change in the content of the movies rather than the actual sound levels” accounts for the perception that films are getting louder. There are more action films today, he points out, and they’re made for 12- to 18-year-olds who expect them to be loud. “People who think movies are too loud,” he says, “are probably seeing films that are just not aimed at them.”

For folk music -- earth music -- the whole amplification process has inherent dangers, because some techie in the sound booth is deciding key issues of cultural representation. But there’s a worse threat: music so loud that you can’t really listen to it, any more than you can look at the sun. It simply surges through you, replacing your own internal rhythms, and you either accept the invasion or, like this reviewer, flee into the night, seeking the comparative peace and quiet of traffic on Cahuenga.

Overkill this extreme usually signals both artistic desperation and a coming juncture in the art form itself. In dance, the radical simplification of postmodernism was born out of just such a juncture after a period of rampant excess. Ditto the rebirth of ballet in Western Europe and America a little over a century ago.

So there’s reason to hope that the attempt to make dance accompaniments inescapably, obnoxiously visceral will soon seem passe, a relic of an outmoded aesthetic. If so, in a few years we can expect the next big thing in dance to be a small thing and the newest major buzz to come to us unamplified. If not, we can always ask Viver Brasil to sell earplugs along with its souvenir T-shirts and CDs.