Did you hear the one about sound coming out of a computer? It's a good one and getting better

These early handicaps limited computer sound to high-pitched beeps that meant something was wrong. Ingenious programmers did come up with ways to play good-quality sound through internal speakers, but too often these same speakers pumped out an overload of scratchy, incomprehensible tones.Forced to do without good sound, users began to think of PCs as purely visual devices and to focus on video applications. Monitor resolutions increased, color depth became lifelike, video cards accelerated 3-D performance and streaming video started to evolve.The first company to focus on quality computer sound was Creative Labs Inc. of Milpitas, Calif., a subsidiary of Creative Technology of Singapore. Creative Labs opened the ears of PC users with an expansion card that did nothing but generate sound. Speakers could be plugged into the Sound Blaster card.For the first time, programmers had options for conveying real information via sound. Meanwhile, the Microsoft Windows operating system began to dominate the PC market, and adding high-quality sound to its visual interface made sense.Because radio was invented first, TV viewers never had to settle for television they could not hear. In fact, for many viewers, good-quality sound matters more than a good-quality picture. In the TV market, sound and picture enjoy equal importance'a balance that consumers expect.In contrast, computer sound has taken a long time to get the attention it deserves. Nevertheless, it has become essential to getting the most out of high-end applications. Even users with basic computing needs can benefit a lot from good sound. It's difficult to find a system for sale without a sound card, and programmers continually come up with new ways to enhance their applications with sound.Sound gives instant user feedback in an unobtrusive yet easily definable way. Different tones or sound snippets can mean different things, from the confirmation that a new window has opened, to a warning that a requested program will overflow the memory buffer. In some cases, audio feedback conveys vital information not otherwise displayed on a screen.One of the most popular applications on the Internet is streaming video. Government agencies use streaming video technology to initiate webcasts or to set up videoconferences with remote sites. As important as the video is, sound is equally important unless the participants restrict themselves to writing everything down.Sound also makes computers accessible to some users who otherwise could not use them. Users with visual impairments can navigate their systems and read documents. In the past this required expensive proprietary hardware, but today sound software can be added to almost any system.A few companies are making sound not just an output but also an input medium. Users have dreamed for years of truly efficient voice recognition, which is coming closer to reality. Again, good sound capability is essential, and you must purchase the right sound card. Despite advances in sound technology, not all cards are created equal.On the one hand, for example, Compaq in its new iPaq, a perfectly good entry-level system, cuts a few corners on the sound card. Standard voice recognition packages return the message that the iPaq's sound quality is inadequate. On the other hand, it works just fine at playing audio. I suspect that the sound card samples the input data at too low a rate.In buying an after-market sound card, make sure it uses wave table synthesis to reproduce sound and not frequency modulation synthesis. In FM synthesis, the card mimics musical instruments according to predetermined formulas. The computer more or less has to fake the sounds of different instruments. Wave table technology instead puts actual samples from leading types of musical instruments right on the card. When a sound request is sent to the card for reproduction, it combines, edits and enhances the samples.Another must: Buy a sound card built to the electronic music industry's MIDI standard. Pronounced middy, it stands for Musical Instrument Digital Interface. A MIDI card can at minimum process the pitch, length and volume differences between musical notes. Some MIDI cards can also process time delays and other factors.Find out whether the sound card is full duplex, which means you can send sound data to it at the same time sound is coming out, like an analog telephone. A half-duplex card would make conferencing almost impossible, as only one person could talk at a time and some voice data would likely be lost.Also determine whether the sound card supports a high sampling rate for both input and output. Sampling takes periodic snapshots of an audio stream. If the sampling rate is quick, as in an audio CD-ROM, the human ear can't tell the difference from the full stream. This is also how film works, by showing a series of still photographs so rapidly that the human eye connects the images and sees motion.Low sampling rates equal choppy sound. A low rate would be anything below about 35 KHz, which can distort the signal. Standard sound cards sample faster than 40 KHz, and good sound is almost guaranteed at the 50-KHz level and higher.Make sure an after-market sound card is Sound Blaster-compatible, which means that it can process commands written for the Sound Blaster. About 70 percent of all PC audio systems follow the Sound Blaster standard.Finally, get a good speaker system. There are some exciting new developments in speakers, including illusionary 3-D sound and true four-speaker surround sound.If you don't have a sound system on your desktop, you're missing out. Or haven't you heard? PC sound has finally come of age.