What Does It Take To Turn The PC Into A Hi-Fi Audio Platform?

Asus Xonar Essence STX

In May of 2009, Asus launched its Xonar Essence ST. The STX, which is almost identical except for its PCI Express interface (and a few other minor differences, notably the lack of daughterboard support for eight-channel audio), followed shortly thereafter.

The Xonar Essence ST(X) was one of the first cards designed specifically to support high-end headphones and bridge the gap between PCs and the high-end audiophile world. Most notably, it included 1/4" TRS connectors, which are rare on add-in cards. The Xonar ST(X) totally came out of left field; nobody imagined a motherboard manufacturer taking that route.

The STX is still sold today at close to its full launch price. How many other sound cards from 2009 can boast such a claim? Asus' design was presumably so effective that when the company introduced its Xonar Essence STU in October of 2013 (almost five years later), it pretty much mirrored the implementation, adding an external enclosure, two volume controls, and some other minor stuff (including 49720 op amps, which aren't popular on the STX, but might have been implemented differently). The Essence One uses somewhat higher-quality components and includes a few more features. But the STX must have been something special, since the Essence One is no longer for sale and the Essence STU doesn't appear to have much momentum.

So, what makes the Xonar Essence STX so successful?

Red: LME48960 op amps (used and spare), Green: stock JRC2114D + LM 4562 (unused), Blue: LME49720 (unused), Pink: TI PCM1792A DAC, Orange: PLX PCIe-to-PCI bridge, Purple: AV100/C-Media AV8788 DSP, Yellow: TI TPA6120A2 headphone amp, Gray: ADC section

One of its perceived strengths is the flexibility to manually swap out the operational amplifiers. Although many would argue that the real-world benefit of doing this is close to non-existent (in fact, you're more likely to make the card operate at a lower fidelity if you swap out the stock JRC2114D op amps which the card was designed for), tinkerers love the option. Tweaking a sound card, since overclocking it doesn't make much sense, resonated with the enthusiast community.

More important is the Essence STX's reportedly well-reviewed sound quality paired to high-end headphones. Asus' implementation of the once-top-of-the-line Texas Instruments PC1792A DAC and TPA6120A2 amplifier was well-received.

And then there's pricing. The Essence One ($600-$1000) and Essence STU ($400), while likely sounding similar, lacked the STX's value proposition at $190.

Because it used PCI Express, Asus' Xonar Essence STX didn't need a dedicated (and expensive) power supply. Except for a three-way gain setting, it also didn't need volume controls. It didn't need an external enclosure or the cables to connect it. The company did choose to add analog inputs and an ADC, though I doubt many of the enthusiasts who bought an STX valued that feature.

If Asus decided to create cheaper and higher-quality sound cards, rather than pricey external DACs, I think it'd win over more converts. A second version, made more affordable by cutting the ADC stages and equipped with a newer-generation DAC, would be great. It's also conceivable that enthusiasts would pay for an optional front-panel display with a quality 32-bit volume control and LCD.

  • SuckRaven
    Bravo ! Awesome, and a very thorough review. Even though as you mention, audio gear is not usually the forté/emphasis of the reviews here, it's refreshing to have someone at least try to cut through the (more often-than-not) overpriced arena of bullshit that is the field of "high-end" audio. I applaud the review, and the effort. Keep up the good work. More please.
  • PudgyChicken
    Just wondering, why not test a Creative X-Fi Titanium HD or something like that alongside the ASUS Xonar? It would be interesting to see some of the differences between different PCIe sound cards in this matchup. However I understand that what you were really going for was showing the difference between price point and form factor at the same time, so perhaps not testing two PCIe cards makes sense.
  • kitsunestarwind
    The biggest thing I have found for the PC is no matter how good your DAC is , if your speakers and AMP are crap, then it will never sound better.People spend big money on DAC's and forget that you need a high Quality amp with very very low THD (total harmonic distortions) and a very good set of Full Range speakers with high sensitivity if you want good sound, instead of crappy (albeit expensive) computer speakers especially sets with a sub.
  • shahrooz
    this article just won Tom's Hardware Readers Elite award
  • maestro0428
    Wonderful article! I love listening to music and do so mostly at my PCs. I try to set up systems where audio is important in component selection. Although we all love drooling over expensive equipment, many times it is not all that necessary for an amazing experience. I'd love to see more! Including smaller, studio speakers as I believe that speakers/headphones are the most important part of the equation. Keep up the great work!
  • blackmagnum
    Don't forget that for PCs: the hardware is as good as its software (drivers).
  • Someone Somewhere
    Agree totally with this. It always annoys me when people say they're spending over $100 on a sound card, especially when it turns out that they're using Optical out, and the whole thing is basically moot.I now have a nice source to link to.
  • 1zacster
    The thing is you can't just pick up two sets of good headphones, try them on different DACs/AMPs and expect to hear major differences, it takes longer than 5 minutes for your ears to adjust to newer headphones and for the differences to actually show. This is like taking food from Left Bank and then bringing in a bunch of hobos and asking them tel tell the differences between the foods.
  • dogman-x
    I use an optical cable from my PC to a home theatre receiver. With this setup, stereo CD audio content is sent as raw PCM to the receiver, not compressed into DD or DTS. These days you can buy a very good quality home theatre receiver for less than $200. Audio quality is outstanding.
  • Memnarchon
    I would love to see ALC1150 in these tests too, since its widely used at most Z87 mobos.