Asus Xonar DX

Verdict:

[+] DX: Fakes EAX 5.0 well; good SNR; half-height; affordable for a PCI-E sound card
[-] 10: Creative isn't impressed; slightly reduced specs from the Xonar D2

Asus has introduced a new PCI-E Xonar sound-card, complete with EAX 5.0 support - even though Creative isn't too happy about the latter. Now, normally, the number three usually follows two, a point underlined by the Book of Armaments, Chapter 2, verses 9-21 (after you've skipped a bit). However, Asus seems to think that the third number used for counting is 'X', as its new Xonar DX is a cut-down version of the Xonar D2X, which was the PCI-E follow-up to the Xonar D2, Asus' first ever sound card. The original Xonar impressed us with its high sound fidelity, but it was pricey and used Dolby Digital and DTS Connect to produce surround sound in games, rather than Creative's EAX.

The half-height Xonar DX costs only £60 and retains many of the qualities of its larger predecessor. The DX is based around the Asus AV100 chip rather than the AV200 used in the Xonar D2. Both chips are actually C-Media Oxygen HD chips, which Asus sorts for quality to determine which should be labelled as AV100s and which get to live on as AV200s. As a result, this means that the recording and playback quality on the Xonar DX both go up to 192KHz with 24-bit sampling. Instead of the high-quality Burr-Brown PCM1796 Digital-to-Analogue Converter (DAC) of the Xonar D2, a more pedestrian pair of Cirrus Logic chips is provided on the Xonar DX. A CS4398 takes care of the front channels of the 7.1 surround playback, while a CS4362A decodes the rest. The Analogue-to-Digital Converter (ADC) is also different from that of the Xonar D2; the latter uses the Cirrus Logic CS5381, while the DX uses the lesser Cirrus Logic CS5361.

While the Xonar D2 offers 118dBA playback, the DX can only muster 116dBA on its front channels, and 112dBA elsewhere. SNR recording has also dropped from 115dBA to 112dBA. In practice, however, these are still very good specifications; all Creative's X-Fi cards but the top-of-the-line, £180 Elite Pro version offer a mere 109dBA. The Xonar D2's other headline act was its support of alternatives to Creative's EAX technology for surround-sound gaming. However, while the Xonar DX retains Dolby Digital support, DTS Connect compatibility has been dropped.

THE NEED FOR EAX

Asus knew that EAX support for Xonar cards would be a massive plus. Earlier this year, the company released a driver update for its Xonar D2, pledging support for Creative's latest EAX 5.0 standard. The update is called DirectSound 3D GX (DS3D GX) and its arrival was shrouded in controversy. Creative immediately claimed that Asus was misleading customers, as the Xonar drivers didn't enable hardware acceleration of surround-sound gaming effects. Instead, Asus has created drivers that trick games into thinking that full EAX 5.0 hardware is available, while offloading the processing of said effects to your CPU. The first version of DS3D GX was rather buggy, but the Xonar DX sports version 2.0, which can handle as many as 128 voices, and works in Windows Vista as well as XP.

When using the GX mode, we were able to use EAX 2.0 in F.E.A.R. with hardware mixing, but not EAX 5.0. With GX mode disabled, these options were greyed out. Battlefield 2's Creative X-Fi option was also available when using the GX mode. As with the Xonar D2, we couldn't hear any difference between the Xonar DX's EAX 2.0 effects and those of a bona fide X-Fi. In fact, we couldn't tell the difference with Battlefield 2 set to Ultra High audio effects either, and there was no sign of glitches. Admittedly, our test PC had a Core 2 Quad Q6600, so it could handle the extra processing load of emulating EAX 5.0 in software. A lesser or single-core CPU might not cope as well as this.

The other significant driver enhancement supported by the Xonar DX is VocalFX, which brings EAX to bear on in-game and Internet chat via three different functions. During online gaming, VoiceEX will blend chatting into the 3D audio environment. When using VoIP apps such as MSN or Skype, ChatEX can make it sound as though you're underwater, or in a bathroom, concert hall or music pub. Finally, Magic Voice will pitch-shift your voice in real time to conceal it, making you sound like a monster, cartoon character, man or woman.

The driver CD also includes PMP Lite, which can encode audio with Dolby effects, but it lacks the loopback capabilities of the full version included with the Xonar D2. Strangely, the Xonar DX still needs external power from a floppy drive power connector. As well as the inclusion of a half-height bracket, there's a TOS-Link adaptor to convert the multifunction mini-jack, which also doubles for microphone and line input duties.

CONCLUSION

The slanging match between Asus and Creative over how close DS3D GX 2.0 really is to true EAX 5.0 is likely to continue, but we found it to be pretty effective during the Battlefield 2 test. One of our criticisms of the Xonar D2 was its less impressive Vista game sound support compared with Creative's X-Fi, and this appears to have been minimised. Although the Xonar DX doesn't have the D2's unbeatable audio fidelity, it still provides sound quality equal or superior to that of the X-Fi. Considering its greatly reduced price, and that Creative still hasn't released a PCI-E X-Fi that we'd recommend buying, the Xonar DX is a valid alternative to a Creative card for gaming, especially if you're limited to using PCI-E slots.

* You can buy the Asus Xonar DX from Scan for £58.74 (price correct at the time of review)

* For more information on the Xonar DX, see Asus's website.

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