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Headphone-oriented sound cards from Asus and Auzentech

Introducing the Xonar Essence STX and X-Fi Forte 7.1

Compared to other segments of the industry, the pace of PC audio innovation has been sluggish in recent years. And that's being charitable. Glacial might be a more appropriate term.

Consolidation within the industry is at least partially to blame here. Creative softened up Aureal, one of its few competitors, before eventually acquiring its assets in 2000. Three years later, Creative picked up 3D audio engine developer Sensaura, further thinning the field. Perhaps scared into submission, other players dropped out of the market on their own accord. Nvidia declined to build on the popularity of its SoundStorm integrated chipset audio, and more recently, codec maker Analog Devices bailed on PC codecs altogether.

As the number of players in the PC audio market has dwindled, so has the number of audio processors. We haven't seen a truly new APU since C-Media introduced the Oxygen HD some two-and-a-half years ago. Creative's X-Fi, still the most powerful audio chip on the market, is even older; it was released way back in 2005.

The seemingly slow pace of audio processor development has likely also been fueled by the fact that modern PCs simply don't do a lot of complex audio processing. Indeed, one could argue that we've gone backward in recent years. Vista's new audio subsystem broke Creative's hardware-accelerated EAX positional effects, stripping 3D sounds from many games. The popularity of console ports, at least among developers looking to target the widest audience possible, has also lowered expectations. Even the latest generation of consoles does seemingly little to push positional 3D audio beyond where it's been on the PC for years. And so we're left with a market that simply isn't clamoring for more powerful audio processors.

To drive demand, sound card makers have been forced to look elsewhere, turning their attention to improving fidelity. Good sound cards have traditionally offered superior playback quality to "free" integrated motherboard audio, and Asus and Auzentech currently make some of the best of the breed. Asus' relatively new Xonar sound cards offer phenomenally good playback quality, as have Auzentech's unique spins on Creative's X-Fi audio processor. Both camps already equip their cards with high-end electrical components, user-replaceable OPAMPs, and the ability to encode multi-channel digital bitstreams on the fly. So what's left to cover?

Headphones, it seems.

Asus and Auzentech have turned out new sound cards with built-in headphone amplification designed specifically for the earmuff crowd—or any of those "real gamers" still running Dustbuster-equipped GeForce FX 5800 Ultras. Naturally, we had to put the Xonar Essence STX and X-Fi Forte 7.1 to the test, not only to see which is best, but to find out whether swanky headphones can hack positional audio in today's games.

First, though, an introduction to the audio processor duopoly that supplies the two cards we're looking at today and indeed dominates the sound card market as a whole. Despite their age, the X-Fi and Oxygen HD are really the only two major players in the discrete sound card world. The latter is often referred to as the CMI8788, or when it's used on a Xonar sound card, as an Asus-branded AV100 or AV200.

An X-Fi with 64MB of X-RAM riding shotgun

The key difference between the X-Fi and Oxygen is horsepower. A revelation when it was released, the X-Fi has an impressive 10,000 MIPs of processing power that it can dynamically allocate to everything from fancy post-processing effects to positional 3D audio acceleration. The X-Fi is also the only audio processor capable of accelerating advanced EAX 5 effects, which, thanks to Creative's ALchemy software, now work with some games in Windows Vista.

The Oxygen HD in AV100 garb

Asus' DS3D GX software pulls a similar trick with the Oxygen HD, and in the process, takes the liberty of emulating EAX 5 effects that had previously only been available on X-Fi cards. The Oxygen chip doesn't have nearly the horsepower of the X-Fi. In fact, it can only accelerate EAX 2 effects in hardware. However, it also has the necessary transistors for real-time DTS and Dolby Digital Live encoding. This capability lets users pass multi-channel game audio over a single digital cable to compatible speakers and receivers, neatly delivering pristine sound unfettered by analog conversions.

The X-Fi can now do Dolby encoding, too, so there's parity with the Oxygen on that front. Both chips also ripple with 7.1 output channels and support for resolutions up to 24 bits and sampling rates as high as 192kHz—high-definition audio, at least in the entertainment biz.

That covers the most important attributes of the Oxygen HD and X-Fi, but what about the cards themselves? Here's a quick look at how the key specifications of each compare.

Asus Xonar Essence STX Auzentech X-Fi Forte 7.1
Audio chip Asus AV100 Creative CA20K2
Digital-to-analog converter TI Burr Brown PCM1792A AKM AK4396VF (front)
Cirrus Logic CS4362A (center, rear, side)
Analog-to-digital converter Cirrus Logic CS5381 Wolfson WM8775SEDS (rear)
Wolfson WM8782S (front mic)
Headphone amp TI TPA612A2 Auzentech
Maximum recording quality 24-bit/192kHz 24-bit/192kHz
Maximum playback quality 24-bit/192kHz 24-bit/192kHz
Analog output channels 2 7.1
Digital output channels 7.1 7.1
Multi-channel digital output Dolby Digital Live, DTS Dolby Digital Live
Street price $140

We'll delve into greater detail with each card in a moment, but while they're lined up side-by-side, it's worth pointing out a few key differences between the two. Despite using different combinations of DACs and ADCs, both cards offer support for 24-bit, 192kHz playback and recording. Interestingly, though, the Essence's analog output is limited to two channels—stereo output, in other words. No such limitation exists for the Forte, which can pipe 7.1-channel audio through either its analog or digital outputs.

The Forte's more robust analog output capabilities won't cost you any extra, either. While few online retailers carry the Auzentech card, it's selling for only $140 at Newegg. According to our price search engine, you can expect to pay at least $37 more for an Essence online.