From the moment your cell phone alarm goes off in the morning (twheep-twheep, twheep-twheep) until the computer shuts down at night (shusssssssstttppp . . . kklluuummppp), electronic sounds surround us. What's all the tccckkk/tccckkk. . .cllpp/cllpp - and other noise - all about?

Now Hear This!

"Sound is very powerful at grabbing your attention," says Philip Smith at The Ohio State University's Institute for Ergonomics. Thus, many sounds act as alerts. The microwave's ding means that lunch is ready. The clothes dryer's buzz means that the laundry is done. And a blaring smoke alarm says, "Get out fast!"

Electronic sounds also provide useful feedback. A digital camera's kkkshupp confirms that you've taken a picture. A touch-tone phone's different phweeps say that you've dialed a number.

Sounds probably help us learn how to work complicated new gadgets. "Because of language, probably, humans get really tied into paying attention to sound and how sound interacts with objects in the world," says psychologist Justin Halberda at Johns Hopkins University in Baltimore, MD. In studies, for example, young children do better at keeping track of objects when unique sounds are linked to them. "So that pairing between sound and object definitely engages attention and engages learning from a very young age," says Halberda.

Sounds also make devices more personalized and humanlike. When early cell phones chreeped, no one knew whose phone it was. Now different ring tones tell whether it's your cell phone going off, and even who's calling. And the wide range of tunes lets phones reflect people's personalities.

Different sounds can affect our feelings. Upbeat tunes, eerie tones, or crashing noises add emotional cues that help us to get more out of video games, tutoring programs, and toys.

Sound also communicates information. Instead of a Web site using just visual information, it may have voice-overs. Designers can thus include more material. Sounds also help people with visual disabilities.

Electronic sounds are often marketing tools. Microsoft's Windows boots up with musical arrnnks. America Online says, "You've got mail." And cell phones wail carriers' jingles when they turn on.

Making Waves

How do electronic gadgets produce sound? "Fundamentally, you have to cause molecules in the air to vibrate," says electrical engineer Albert Titus at the University at Buffalo. This produces sound waves, which make our eardrums vibrate. This, in turn, triggers reactions that stimulate nerves, so our brains can ultimately interpret the sound.

Inside a microwave, says Titus, the end of the cooking cycle probably triggers a small piezoelectric device, "which is something that vibrates when you apply a voltage to it." Piezoelectric materials include different ceramics, some metals, and quartz.

Devices with more advanced sound features use actual speakers that produce richer, fuller sound. Thus, cell phones don't just chime or chirp. Polyphonic or MIDI ring tones have four or more layers of sound. And MP3 ring tones are just like music that you'd carry on a portable music player. Whatever their format, all cell phone sounds are digital files that get activated by certain machine functions.

"Whether it's the simplest beeping ring tone or your favorite song that's ringing, it's still a series of ones and zeroes," explains Keith Nowak at Nokia. The more advanced a ring tone is, the bigger its file size. Soon, Nowak says, cell phones will have built-in hard drives that can hold whole music collections of over 1,000 songs.

How does someone choose which sounds are built into a commercial device? Smith says that this is an art that is "very much like writing music." Partly the decision depends on the designer's purpose and message. The users' backgrounds, cultural references, and other factors also enter in.

Too Many Grrrnnttts and Fwheeeeps?

Too many sounds can cause problems, though. If users can't sort out when to pay attention, says Smith, "the designer loses control."

Optimally, Titus says, engineers will include off switches, adjustable volume, and other controls. For example, kids' toys shouldn't dddaawwmmmm nonstop or get stuck on a single w-w-w-w-word.

Of course, people need to know when to use the Off switch. No one wants to hear a cell phone during a concert or at a fine restaurant.

Even at home, too much electronic noise builds stress. Sound adds to the intensity of using computers, video games, and other devices. "They're not natural sounds, and because of that, they are more intrusive," says psychologist Larry Rosen at California State University at Dominguez Hills.

When young people get caught up in instant messaging, e-mail, gaming, and other computer work, they can wind up feeling jumpy, tingly, or hyper. "What's left over is a really heightened nervous system," says Rosen.

So, enjoy the bleeps, squonks, sgzzes, and other sounds your gadgets squawk. But save some quiet time, too.