Back in the prehistoric 1970s, one of life's little pleasures was the ability to slam down a telephone on annoying callers. Now, thanks to the rise of cordless phones, the best you can do is fiercely poke the off button _ or, if money is no object, throw the receiver into a wall.
The slamming phone, like dozens of once-familiar sounds, is headed for extinction. As technology advances, more and more noises _ the pop of flashbulbs, the gurgle of coffee percolators, the clatter of home-movie projectors _ are fading into oblivion.
While audio junkies scramble to preserve samples for future generations, psychologists debate the consequences of this noise exodus. Some foresee a sonic revolution _ one that could launch a surprising wave of silence and perhaps force Hollywood studios to rethink the way they tell stories.
Inside a bombproof vault a few blocks from the White House, Dan Sheehy is surrounded by audio ghosts: the clicketyclack of typewriters, the tumble of glass bottles inside a soda machine, a 1960s-era telephone ring.
Here, sonic blasts from the past are entombed in a hodgepodge of vinyl records, compact discs and reel-to-reel tapes. "We are a museum of sound," said Sheehy, whose job is to preserve America's acoustic heritage for an obscure branch of the Smithsonian Institution.
Sounds are like smells, he says. They can transport the listener to another time and place. The buzz of an airplane propeller sends Sheehy's mind back to hot afternoons in 1950s Bakersfield, Calif., playing in the yard while aircraft sputtered overhead. "The sound immediately triggers memories of time and temperature," he said.
A handful of obsolete noises are so ingrained in our consciousness that filmmakers and advertisers still use them to evoke audience reactions. In the 2002 movie Undercover Brother, for instance, a phonograph needle scraping across a vinyl record signaled an abrupt halt to the action.
The emotional power of vintage sounds might explain the popularity of cell-phone ring tones that mimic rotary telephone bells. "It's one of the biggest ring tones we sell," said Tom Valentino, president of Valentino Production Music, the nation's oldest sound-effects warehouse. In a similar vein, slot machines that pay out vouchers instead of cash often play a recording of cascading coins because research found customers missed the jackpot noise.
Valentino has heard a lot of sounds come and go over the years. In 1932, his father got into the business by recording a milk wagon traveling down a New York street, the first of what is now a library of more than 50,000 sound effects. (The elder Valentino worked with Orson Welles on War of the Worlds and once captured the chug of a steam train running full tilt by greasing the railroad tracks at Grand Central Station so the locomotive couldn't move.)
Many of the company's recordings are now historical relics. A slamming car door from the 1960s, for example, sounds more metallic than today's rubberized thunk.
Sounds are always mutating, Valentino said, but the pace accelerated after the advent of computerization. Electronic cash registers eliminated the ka-ching of their ancestors; digital cameras erased the traditional shutter-click and advancing-film noises of their predecessors; PowerPoint presentations chased away the clunks and whirs of slide projectors.
The lifespan of sounds seems to be shrinking, Valentino said: "We sent our engineers to Fort Bragg 25 years ago to record military tanks. All those sounds are now totally historical."
So are old pinball machines, car horns and pull-chain toilet flushes. Even the scratch of chalk on a blackboard is being exiled by the squeak of markers on dry-erase boards.
For most of history, the soundscape rarely changed.
"From the birth of man until the late 1800s, the predominant sounds human beings heard arose from nature," said Rex Julian Beaber, a psychologist and attorney in Los Angeles.
The Industrial Revolution upended all that, unleashing a cacophony of manmade noise. Today, another sonic revolution is under way. Although many observers fear the planet is about to become louder (check your local Dolby surround-sound cinema), Beaber foresees a wave of silence. Modern technologies are turning down the volume of our mechanized society, he says.
So far, the differences are subtle, such as the click of a TV channel knob being muzzled by electronic remote controls. But eventually, when the roar of the internal combustion engine is muted by the whir of electric or fuel-cell motors, "we will return to the world from which we came, one in which the big sounds we hear are from nature," Beaber predicts.
Why do some antique sounds, such as steam locomotive whistles, remain widely missed while others go to the graveyard barely noticed?
Part of it is personal taste. "Noise for one person is hi-fi for someone else," said Steven Feld, a professor of anthropology and music at the University of New Mexico in Santa Fe.
In the United States, movies and television have trained the human ear to think some studio-created sounds are more "real" than the originals. In winter scenes, for example, the crunch of someone walking across 50 pounds of cornstarch seems more authentic than the muffled noise of real snow, Valentino says.
However, the ability of Hollywood sound engineers to conjure audience emotion will fade in the near future, Beaber predicts.
Right now, sounds such as creaking doors help create drama on the screen, he said. But the day is coming when door technology, which hasn't changed in centuries, will switch to an airtight, silent mechanism like something out of Star Trek, he said.
"Once people have lived in a world where doors don't creak," that sound effect will lose its dramatic punch, Beaber said.
Eventually, Hollywood will have to rely more on visual cues than audio effects, Beaber said.
Nostalgia for expired noises is similar to not noticing the hum of a refrigerator until it shuts off. "You only remember the sound in retrospect," and then you quickly forget about it again, said Diana Deutsch, a psychology professor at the University of California, San Diego.
When compact disc players first hit the market, music lovers initially grew hyper-aware of all the cracks and pops on their old phonograph records, she noted. Some people even missed the scratches, comparing the background noise to the crackle of a fire.
In the long run, every audio dinosaur will suffer the same fate, Beaber said. Air raid sirens, stock tickers, Pong video games _ each one carries significance for the generation that grew up with it, but once that generation dies, the sound, too, becomes lifeless.