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Sound alternatives: Sound card round-up

Pick a peck of sound cards

THIS ROUND-UP HAS BEEN a long time coming. In fact, I think a valid argument could be made that this review was cursed. Every time I thought I was making progress, a new card would come in that needed an involved feature examination, and many times it would introduce some new point of comparison that would require going back over all the previous cards. To top it all off, last month, a day or two before I was planning on doing all the listening tests, my eardrum ruptured. It's been over a month, and it's still not back to normal. Anybody want to challenge me on the curse issue?

I didn't think so.

Still, once I fought my way past whatever audio spirit I angered in my quest, I found the state of sound cards (as far as the cards presented here went, anyway) to be more varied and interesting than I expected. Finally, I unwittingly managed to take a prescient look at a possible new direction in mainstream PC audio. Read on to see what I uncovered.

PC sound 101
Before we go any farther, I should offer a brief primer on the major components of PC sound cards. I'll skip over the more obvious bits (if you don't know what a speaker output jack is for, you should probably just move along now) and concentrate on the core of the card, which consists of the audio processor chip and the CODECs. The audio processor is more or less what you'd think it is; it does the work of manipulating the sound in the digital domain. Depending on the capabilities of the processor chip, it might be responsible for sample rate conversions between different sound sources, or even adding in digital effects such as chorus or reverb. The audio processor is certainly the brains of the operation.

But there's another piece involved, and it's more important than you think. The audio processor does a bang-up job of manipulating sound in the digital domain, but unless you have speakers with a digital input, that sound is going to need to be converted back to analog at some point. Additionally, many of the audio sources you want to put into your computer start out as analog, as well, so a sound card needs some way to change them to digital so it can do something with them. These conversions are the domain of DACs (digital to analog converters) and ADCs (analog to digital converters). Many audio cards have chips that perform both of these functions; they are typically called CODECs, because they are capable of both encoding analog to digital and decoding digital to analog.

Setting aside ADCs for a moment, DACs are a religion among audiophiles. Many would tell you that a DAC is one of the most important components in a digital playback system, and there are a number of stand-alone audiophile DACs costing hundreds or even thousands of dollars.

Of course, when you're putting together an entire PC audio solution for under $100, you have to make some compromises. Most of the cards in this round-up use CODEC chips, which combine the functions of a DAC and an ADC into one piece of silicon. One even packs the A-D and D-A conversion components right into the audio processor itself for an all-in-one solution.

While the audio processor chip and CODEC chips are two of the biggest variables here, they're not the only ones. Drivers can make quite a bit of difference in the functionality and usability of a card. Additionally, the number and type of input and output connectors on a card can make a difference, depending on your application. We'll be taking a look at all these considerations and more.

Now that we've gotten the basics out of the way, let's start looking at the cards themselves in detail.