Sound Card Buying Guide

Sound card components

Your computer's CPU is responsible for the whole show, and motherboards can run basic computer speakers without any help. However, for the best sound reproduction, a sound card takes the load off the CPU for the high-end gamer or audiophile using 5 basic components:

• Motherboard connections bring in data from the hard drive and electricity from the power supply.
• Memory chips hold data during processing.
• Digital signal processors (DSP) turn digital computer files into analog audio signals. The DSP has two parts: the digital-to-analog converter (DAC), for data file to speaker; and analog-to-digital converter (ADC), for microphone to data file.
• Component connectors (jacks and plugs) bring signals from outside sources or send them to computer speakers.
• File transfer protocol is software that allows files from different sources to talk to each other. The common FTPs are Sony/Philips Digital Interface (S/PDIF), which uses coaxial or optical connections to connect with the sound card, and Musical Instrument Digital Interface (MIDI), which connects electronic instruments and synthesizers to computers.

Sound card buying tips

For an explanation of technical terms, like signal-to-noise ratio (SNR), total harmonic distortion (THD) and frequency response, the Overstock.com audio buying guide is a great resource.

There are two basic kinds of audio card users: Gamers want 3-D sound effects in synch with the game's video frame-per-second rate (generally 30 or 60 fps). Audiophiles want clear, high-fidelity sound reproduction, just as they would in a home theater system. Choose the sound card that meets your end-use needs:

Resolution
Also called "bit rate," resolution measures the ADC and DAC capacity. CD-quality sound is 16-bit; DVDs, DVRs and high-end computer games use 20-bit or 24-bit codes.

Sampling rate
The amount of data a sound card can process per second is measured in kilo-Hertz (KHz). A higher sampling rate means more accurate audio reproduction. The CD standard is currently 44.1KHz; DVDs requires 96KHz.

Output channels
Many new computers have excellent built-in speakers. However, some users want better sound than the built-ins can provide. For good stereo reproduction, each speaker must have its own channel. Think of a conference call -- even though it's the same conversation, every caller has his own telephone number. Audio "output channels" is the number of external speakers the sound card will support, or the number of speakers you can connect to your computer. Output channels are listed two ways: as the total number of speakers you can connect (2, 4, 6) or the surround sound number (5.1-, 6.1- or 7.1-channel). The ".1" is the sub-woofer (the deep notes); the 5, 6 or 7 is the other speakers in the system. Overstock.com's speakers buying guide can help you choose a good external speaker system.

Sound card terminology

Interface: The technical term for component connector; modern electronics use several different types of connectors.

• TRS: Also called phone plugs (now mostly seen used by telephone operators in old movies) have a single prong. The first phone plugs were 0.25 inches wide; miniature (3.5mm) and sub-miniature (2.5mm) TRS connectors are currently the most common type used in portable consumer electronics like MP3 players, PDAs, etc.


• RCA: Also called phono plugs (first used to patch phonographs into external amplifiers), these connectors have a single prong surrounded by a metal ring. Phono plugs are very common connectors for consumer audio and video devices.


• DIN: DIN connectors are similar to RCA plugs: a metal ring with two to eight prongs inside. Each pin carries a different sound or data channel, and DIN connectors are still used in computers for mice, keyboards and speakers, but they are becoming less common.


• USB: The newest plug is the rectangular-ended, almost universal connector created specifically for computers. It is replacing many other types for computer-compatible components. The point is not to know all these technicalities, simply to know which connector is on your computer, your sound card and your speakers. Don't worry if they don't match, there's an adapter for every occasion.

Expansion cards: Add-on internal computer components that can be significantly better that the factory-installed devices.

Integrated sound: Most motherboards have an audio capability; this is integrated sound. Reviewers recommend expansion cards for those who want truer theater-grade sound.

Sound cards care

Your Sound card should require no maintenance. If it does, take it to a computer repair service; a sound card is not a do-it-yourself project. (Always get an estimate before authorizing work; it might be quicker and less expensive to replace an old sound card.)

Other sound card features

A USB sound card is actually an external expansion card that plugs into the computer through a USB port. It works the same way an internal sound card does. These can be especially useful for laptops which have limited space inside for expansion cards.