If you aren't already talking to your computer, you probably will be soon. Whether you're making low-cost phone calls over the Internet, dictating e-mail via the latest voice recognition software, or chatting with fellow online gamers, you need to make sure your PC hears you loud and clear.

Accurately converting your voice into the zeroes and ones that move through your computer requires a good microphone, which translates the vibrations of your voice into analog electrical signals; and a good sound card, which turns the analog signals into digital form.

Stand-alone Voice-over-IP phones often cost $100 or more. For less than half that price, you can buy a headset that combines a microphone with earphones. Such headsets are required for making PC-to-PC and PC-to-phone calls via most popular VoIP services. (Click here for Jeff Bertolucci's review of two Wi-Fi phones and here to read Associate Editor Liane Cassavoy's review of ScanSoft's Dragon NaturallySpeaking 8 voice recognition software.)

Cancel the Background

Devices with built-in noise canceling position one microphone to capture voice, and point another in the opposite direction to capture background noise. This allows the device to remove some background noise, improving sound quality.

I've had good results with Logitech's Premium USB Headset 350 (about $45 online). And when traveling, I like the collapsible DSP-400 from Plantronics (about $40 online; see Figure 1). Both products connect to the PC via USB.

You can also use a stand-alone microphone and your PC's speakers for sound. The $35 Superbeam SoundMax Array Microphone from Andrea Electronics has two microphones mounted about 4 inches apart that do a pretty good job of capturing your voice from a few feet away, such as while the device is set atop your PC's monitor.

Speaking in Digital

The sound equipment in nearly any PC that's less than three years old can do this, but older and budget computers may not be up to the task. Here are two features to look for.

Full duplex: A full-duplex sound card can process inbound and outbound signals at once, which is very important when you're carrying on a live conversation. Half-duplex cards process only one signal at a time, like a walkie-talkie. This often clips the beginning and ending of spoken sentences.

To check for full-duplex sound, simultaneously play and record a .wav file using the Windows Sound Recorder utility: In Windows XP, click Start, All Programs, Accessories, Entertainment, Sound Recorder (the steps are similar in older Windows versions). Repeat the steps to open a second Sound Recorder window. In the first window, play a .wav file that's at least 30 seconds in length. While it is playing, go over to the second window and record the file. If the file records, your card is full duplex.

Noise reduction: Electromagnetic fields in your PC can distort analog voice signals before they're digitized. To reduce this static, get a USB microphone, which digitizes the signal before it enters the PC. If your mike plugs into the sound card, Andrea Electronics has a USB adapter for $50.

Send your tips and questions to kirk_steers@pcworld.com. We pay $50 for published items. Kirk Steers is a PC World contributing editor.