The buzz of an airplane propeller sends one's mind back to hot afternoons in 1950s Bakersfield, playing in the yard while aircraft sputtered overhead. The sound immediately triggers memories of time and temperature.

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 cellphone 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 also 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.