Audio Hardware - Theater and Surround Sound Considerations

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If you're a serious gamer or DVD movie lover, you won't be content with ordinary stereophonic sound. Most audio adapters now support front and rear speakers, and many of the best audio adapters also support Dolby-compatible 4.1 and 5.1 speaker setups.

To ensure you get the sound you expect from four or more speakers, check the following:

• Use the properties sheet for your audio adapter to properly describe your speaker setup. This includes selecting the number of speakers you are using, setting options for 3D environmental audio and positional sound such as reverb, and setting up your subwoofer if present.

• Make sure you use the correct cabling between your speakers and audio adapter. If you are planning to use AC3/Dolby speaker setups, such as 4.1, 5.1, 6.1, or 7.1, be sure you use the correct S/PDIF connection and configuration. This varies from audio adapter to audio adapter; check the vendor's Web site for details.

• Make sure you have placed your speakers correctly. In some cases you can adjust the audio adapter's properties to improve sound quality, but sometimes you might need to move the speakers themselves.

• Make sure you have connected your speakers to the proper jacks. Mixing up left and right or front and rear causes poor sound quality.

Typical Speaker Setups

The simplest audio configuration available today is stereo, which uses two speakers placed to overlap sound. Most audio adapters now support at least four speakers, but depending on the audio adapter, settings, and sound output options in the program, the rear speakers might simply mirror the front speakers' output, or you might have four distinct sound streams.

4-point surround sound uses four speakers plus a subwoofer to surround you with music and gaming sound effects; the four speakers are placed around the listener, and the subwoofer is usually placed near a wall or in the corner to amplify its low-frequency sound. The subwoofer in stereo or four-point surround sound setups is not on a separate circuit but is controlled by the same signals sent to the other speakers. A stereo speaker system with a subwoofer is often referred to as a 2.1 speaker configuration, and a four-point surround sound configuration with a subwoofer is often referred to as a 4.1 speaker configuration.

5.1 Surround sound, also referred to as Dolby Digital or DTS Surround sound, uses five speakers plus a subwoofer. The fifth speaker is placed between the front two speakers to fill in any missing sound caused by incorrect speaker placement. The subwoofer is independently controlled. This is the preferred sound system for use with DVD movies. Most lower-cost audio adapters lack support for 5.1 Surround sound.

Some of the latest sound cards support 6.1 and 7.1 Surround sound. The 6.1 configuration resembles the 5.1 Surround setup but adds a middle speaker along with a subwoofer. 7.1 Surround sound uses left-middle and right-middle speakers to flank the listener, along with a subwoofer. Depending on the sound card, some cards play back 5.1 or greater Surround sound configurations with analog speakers only, whereas others can also transmit Dolby Digital (AC-3), DTS Surround, or Dolby EX digital audio through the SPDIF digital audio port to a home theater system.

Microphones

Some audio adapters come complete with a microphone, but most do not. You'll need one to record your voice to a WAV file. Selecting a microphone is quite simple. You need one that has a 1/8'' minijack to plug into your audio adapter's microphone, or audio in, jack. Most handheld microphones have an on/off switch. However, you can also use the Mute control in the audio mixer to shut off the microphone.

Like speakers, microphones are measured by their frequency ranges. This is not an important buying factor, however, because the human voice has a limited range. If you are recording only voices, consider an inexpensive microphone that covers a limited range of frequencies. An expensive microphone's recording capabilities extend to frequencies outside the voice's range. Why pay for something you won't be needing?

If you are recording music, invest in an expensive microphone, but be sure that your audio adapter can do justice to the signal produced by the microphone. A high-quality microphone can produce mediocre results when paired with a cheap 8-bit audio adapter.

Your biggest decision is to select a microphone that suits your recording style. If you work in a noisy office, you might want a unidirectional microphone that will prevent extraneous noises from being recorded. An omnidirectional microphone is best for recording a group conversation.

Some audio adapters include a microphone. This can be a small lapel microphone, a handheld microphone, or one with a desktop stand. If you want to keep your hands free, you might want to shun the traditional handheld microphone for a lapel or desktop model. If your audio adapter does not come with a microphone, see your local stereo or electronics parts store. Be sure that any microphone you purchase has the correct impedance to match the audio adapter's input.

If you're using software such as Dragon Naturally Speaking, IBM Via Voice, Philips FreeSpeech, or other voice-recognition software, use the microphone supplied with the software or choose from alternative models the software vendor recommends. Run the microphone setup program again if your software has trouble recognizing your voice. Some models feature a battery pack to boost sound quality; be sure to check the batteries and replace them to keep recognition quality high.

If you're talking but your voice-recognition or recording software isn't responding, check the following:

• Incorrect jack. It's easy to plug the microphone into the wrong jack. Try using a magic marker to color-code the microphone wire and jack to make matching up easier if your microphone or audio jack isn't color-coded or uses competing standards.

• Check the recording volume in the mixer control. This usually defaults to Mute to avoid spurious noise.

• Make sure the microphone is turned on in the voice-recognition or recording software. You must click the Record button in recording software, and many voice-recognition programs let you "pick up" the microphone for use or "put it down" when you need to answer the phone. Look for an onscreen microphone icon in the Windows System Tray for fast toggling between modes.

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This chapter is from Upgrading and Repairing PCs, 16th edition,by Scott Mueller. (Que Books, 2004, ISBN: 0789731738).  Check it out at your favorite bookstore today. Buy this book now!

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