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ASUS Xonar DX 7.1 Sound Card

Date: May 28, 2008
Author(s): Rory Buszka

ASUS finally antes up to the bang-for-the-buck table with a value-priced product in their Xonar family of performance audio cards. It’s got a solid feature set, and debuts with ASUS’ new DS3D GX 2.0 environmental DSP, but does it break new ground in the price/performance department?



Introduction

We took our first look at the ASUS Xonar range of audio products with the Xonar D2, which we reviewed in September of last year, and the first impressions of ASUS’ approach to high-quality desktop audio were highly favorable. However, the first round of Xonar parts, the D2 and D2X sound cards, were decidedly high-end parts, commanding a high-end price as well, though priced competitively in relation to Creative’s top-end Sound Blaster X-Fi Elite Pro.

I was responsible for that first review of the Xonar D2, and as I tried to gauge our visitors’ responses to the product, I soon found that while enthusiasts were impressed by ASUS’ initial Xonar product offerings, they longed for a budget-conscious offering. ASUS released the Xonar U1 soon afterward, an affordable external USB sound card based on the same C-Media chipset as the other Xonar products, but the void of an affordable, high-quality Xonar card still remained.

In response to the continual requests for a value-oriented Xonar product, ASUS developed the Xonar DX sound card – a budget-priced card which contains much of the same technology as the reference-quality D2 and D2X cards, but with a few tradeoffs made in order to keep the cost low. These tradeoffs are primarily in the area of component quality.

Where the Xonar D2 and D2X used cost-no-object reference-quality Burr-Brown DACs and opamps in the output stage for all seven channels, the DX uses components more typical of the mass market offerings from Creative, Sondigo, Razer, and others. We’ll explore these differences in more detail later.

The Xonar DX also differs from the D2 and D2X cards in its form factor – while the D2 and D2X are full-height cards, the DX features a low-profile design that allows it to fit inside some smaller home theater PC cases. It also leaves the PCI bus by the wayside, offering only a PCI-Express version that occupies a single 1x slot. It claims a lower 116dB signal-to-noise ratio, but only on the front left and right channels, following the rating convention used by many other high-profile sound card manufacturers.

The ASUS Xonar DX sound card debuts with version 2.0 of ASUS’ DirectSound 3D Gaming Extensions (DS3D GX), a competitor to Creative’s EAX. In fact, ASUS’ claims that DS3D GX 2.0 could duplicate EAX 5.0 functionality within a software driver extension pack drew some controversy earlier this year, when the Xonar DX was first introduced. We covered this story in April, in a separate article comparing the two approaches to environmental DSP in games.

The burning question in the minds of those who’ve lusted after the more expensive ASUS Xonar sound cards is this – exactly how much of the high-end experience is sacrificed with the lower-priced DX card, when compared to the D2 and D2X? In this review, we’ll take a look at this newest product in ASUS’ successful Xonar line, and discover the answer to that question.

First Impressions

Unboxing the ASUS Xonar DX is a little less involved than with its more expensive cousins. Instead of the multi-layered PET shell that the Xonar D2 and D2X cards arrive in, the Xonar D2 is packaged in the more traditional cardboard insert, and protected in a Mylar bag to prevent harmful static discharge to the sensitive components.

Also included in the Xonar package are the instruction manual, the installation disc, a Toslink to mini-optical connector, and a low-profile mounting bracket for use in a slim HTPC or small form factor chassis. The card itself ships with the full-height mounting bracket already installed. ASUS even includes a pair of additional bracket mounting screws for the low-profile bracket, if one should go missing during the exchange. You’ll still need a tiny jeweler’s screwdriver to drive the miniscule screws, however, and care should be taken not to strip the fine threads.

The Xonar DX card itself isn’t as spiffy as the D2 or D2X, and it’s lacking the EMI shield. It’s also not as physically massive, being designed for low-profile conversion. Components are mounted to both sides of the circuit board to facilitate the low-profile design.

The circuit board is the same black PCB used for the Xonar D2 and D2X, but the mounting bracket is plated with black chrome instead of gold. The inputs are still gold-plated, however, for low-resistance conduction. There’s not much to differentiate this card from other offerings, with the exception of the large ASUS logo silkscreened onto one face of the card.

ASUS Xonar DX Specifications

Among the list of specifications for the Xonar DX card, you’ll notice that not all eight channels (front L/R, center, side L/R, rear L/R, LFE) are rated equally for signal-to-noise ratio and total harmonic distortion. With the Xonar D2, ASUS touted identical performance characteristics on all eight analog output channels, but other manufacturers play similar specification games as ASUS does with their value-priced DX card, giving only SNR and THD specs for the front left and right channels, and using lower-quality parts on the output stage for the other six channels.

The Xonar DX is capable of 5vpp swings on its outputs, just like the D2 and D2X, however, so head-philes with high-impedance headphones (my reference Beyerdynamic headphones are rated at a stiff 250 ohms) can expect trouble-free performance, even at high output levels. Also, the Xonar DX manages to pack in an optical digital output jack despite the card’s low profile, though you’ll give up use of the mic/line-in port while using the optical output.

Now that we’ve given the card an initial once-over from a design, specification, and bundle standpoint, let’s take a more in-depth look at the card’s features and onboard components.

Features Overview

The ASUS Xonar DX sound card is a value-oriented relative of the reference-quality Xonar D2 and D2X cards, but that doesn’t mean that ASUS has gone light on the feature set of this attractive new option in the price/performance race. Let’s take a look at the design features of the Xonar DX sound card. Has ASUS made any performance-hobbling engineering tradeoffs in their pursuit of the price/performance crown?

Let’s start with the heart of the Xonar DX – the ASUS AV100 audio processor. Though it bears a different model designation, it’s still a rebranded C-Media CMI-8788 OxygenHD audio processor – in fact, it’s the very same one that’s at the core of the Xonar D2 and D2X sound cards, though these units didn’t test at the higher 118dB SNR spec, so they fit within a lower 116dB specification ‘bin’, in much the same way that CPUs with the same physical core might ‘bin’ at different maximum stable frequencies.

The signal-to-noise ratio of the audio processor may be dependent upon slight variations in the manufacturing process that affect noise infiltration at various stages in the internal signal chain, so rather than reject these parts, ASUS has elected to use them in their value-priced offerings. Of course, ASUS’ decision to re-brand an off-the-shelf audio chipset is one I’m willing to endorse here, especially since the CMI8788 boasts specs that embarrass many competing current-generation audio processors.

The next place to look for differences between the Xonar DX and its higher-priced siblings is in the DACs, or Digital-to-Analog Converters. These ICs are responsible for converting the digital output of the audio processor to an analog signal that may be fed into the output-stage opamps, and can have a significant effect on audio quality.

In the case of the Xonar DX, ASUS foregoes the reference-quality Burr-Brown DACs of the D2 and D2X for less-expensive Cirrus Logic DACs. Where the eight channels of the Xonar D2 and D2X were handled by a tandem pair of Burr-Brown PCM1796 four-channel DACs, the front left and right channels of the Xonar DX are handled by a Cirrus Logic CS4398 stereo DAC (120dB dynamic range), while the other six channels are handled by a Cirrus Logic CS4362A 6-channel DAC (114dB dynamic range).

On the Line In side of things, the Xonar DX uses a Cirrus Logic CS5361 ADC (114dB dynamic range). (For those of you sharp enough to decipher ADC as Analog-to-Digital Converter, good for you – it’s a DAC in reverse.) While the Burr-Brown parts on the Xonar D2 and D2X are likely to be found in high-end, high-dollar audiophile stereo gear, the Cirrus Logic parts are of a more mass-market nature, and significantly less expensive in quantity.

Instead of the Burr-Brown OPA237 opamps used in the analog output stage of the Xonar D2 and D2X cards, the Xonar DX gets by with more plain-vanilla Texas Instruments 4580 opamps (0.0005% THD) for the front left and right channels, and TI 5532 low-noise opamps for the other six channels. All of the Xonar D2’s output-stage opamps are located on the back face of the PCB, along with their corresponding DACs.

The CMI8788 audio processor isn’t designed for communication across the PCI-Express bus, so short of holding C-Media’s feet to the fire to develop a PCI-E audio chipset, ASUS chose instead to pair the AV100 with a PLX PEX8111 PCI-Express bridge chip, which creates a single-channel PCI bus on the card itself and allows the Xonar DX to function as a PCI Express device.

The input panel of the Xonar DX card has five 3.5mm stereo mini-jacks, which are gold-plated for low-resistance conductivity. Preferring substance over bling in this price category, the Xonar DX’s jacks lack the multicolor illumination of the D2 and D2X, so you might need a flashlight when hooking up the Xonar DX in a low-light area. In this photo, the left-most input jack also contains an optical signal transmitter, for use with the supplied Toslink-to-Mini-Optical connector if you use Toslink cables (like most of the audio industry today).

One more notable difference between the Xonar DX and its more expensive brethren is that it features a front-panel audio I/O header. The D2 and D2X omitted this feature, much to the consternation of some purchasers – though a quick look at my Creative Sound Blaster X-Fi XtremeGamer card revealed that it, too, lacked a front panel I/O header. The four cream-colored objects on the PCB surrounding the front panel header are actually quad-pole relays that switch mechanically from the rear panel I/O ports to the front panel header when a device is plugged in.

The Xonar DX also provides a single 4-pin audio input header, for use with older CD-ROM drives that have direct analog audio outputs. There’s not much reason to worry about one of these, nowadays (with most audio being handled digitally via software) – but the Xonar DX provides one, for an added measure of flexibility. One feature that’s missing from the DX that’s present on the D2 and D2X, however, is the ALT (Analog Loopback Transformation) feature, which would automatically create a direct path on the circuit board between the analog outputs and the analog line-input.

One final thing to mention on the hardware side – the Xonar DX requires an additional 4-pin Berg (floppy-style) power connector. I’m not sure why the PCI Express 1x connector would fall short when it comes to the card’s power requirements – the PCI version of the Xonar D2 had no need of any additional power supply besides what it could draw from its PCI slot connector.

Still, be sure you’ll be able to meet this additional requirement – the Xonar DX won’t function without it. The X-Fi Fatal1ty XtremeGamer Professional Edition card I had on hand also has a 4-pin power connector, but functions just fine without it, I found, but the same is not the case for the Xonar DX.

We’ve just taken an intensely technical look at the design of the ASUS Xonar DX sound card – but how does its feature set translate into performance? We’ll take the card for a spin shortly, after a brief word about the software drivers.

Driver, Audio Testing

On the surface, the driver software for the ASUS Xonar DX audio card appears identical to the driver for the Xonar D2 card we tested in September of last year. You can read our comprehensive look at the Xonar driver’s control panel in that review. However, there are a few differences, primarily relating to the available functionality on the card itself – while the DX card doesn’t offer the ALT feature of the D2 and D2X, it does offer a front panel input header, which requires a different set of software controls for the onboard relays.

Also, the Xonar DX card uses a single jack for the line in, microphone input, and optical digital S-PDIF outputs, so the driver software needs to be able to determine, for instance, whether you’ve plugged in a microphone or a stereo line-level signal to the input jack.

The Xonar DX’s driver software debuts version 2.0 of ASUS’ DirectSound 3D Gaming Extensions, a software extension to the Xonar D2’s software-based DSP that enables functionality comparable to Creative’s EAX 5.0 when playing EAX 5.0-compliant games. The advantage of the ASUS approach is apparent here – while subsequent versions of EAX require Creative to develop an entirely new hardware DSP in their audio processors, ASUS simply needs to deploy a software update that enables the new functionality.

The software-based DSP of the Xonar cards will consume a few more CPU cycles than Creative’s hardware DSP when processing EAX-style effects at EAX 5.0 levels of depth and complexity, but as you’ll see in the testing section, this doesn’t amount to much – even on an older CPU like the AMD Athlon 64 X2 5200+.

Another important point to mention – ASUS touts significantly better support for EAX 5.0 functionality under Windows Vista than Creative’s own solution, which relies on a translator program for DirectSound calls (Creative ALchemy) to replace the Hardware Abstraction Layer, a design feature of Windows 2000 and XP that was removed in Vista. Games that use OpenAL to handle their audio calls, however, don’t have any trouble under Vista with either manufacturer’s cards.

Audio Testing

And now we dive into the testing portion of the article, with a look at the audio performance of the Xonar DX compared with two other cards: the Xonar D2 and the Creative Sound Blaster X-Fi Fatal1ty XtremeGamer Professional Edition. To examine the audio performance characteristics of each card, the test of choice when laboratory-grade testing equipment isn’t available is the ‘loopback’ test, where the analog output from the card’s front left and right channels is routed through the card’s line-in jack.

This isn’t a perfect test – for one, it’s highly dependent on the quality of the card’s input stage as well as its output stage. With the Xonar D2 and D2X, it seemed ASUS had figured out the key to performing well in this test, endowing their cards with excellent input stages, so I’ve also taken the liberty of routing the X-Fi XtremeGamer’s output through the Xonar D2’s exceptionally clean input stage for one test, for a more direct comparison between the high-end cards.

For all testing, I’m using my reference PC, which is a modest mid-range configuration that’s representative of the majority of enthusiast systems in use today. For monitoring the cards’ output, I use a set of German-made Beyerdynamic DT 770 headphones. Their stiffer 250-ohm impedance is tougher for many sound cards to drive, but a card that has plenty of drive voltage on tap has no trouble extracting incredible sound from these sealed cans, with accuracy and detail.

I’ve had significant luck in pairing them with the Xonar D2, but they’re an excellent reference for any source. For each sound card, I uninstalled the other cards’ drivers and installed only the driver for the card presently under test. RightMark Audio Analyzer version 6.0.6 was used for all testing, and every test was performed with 24-bit resolution at a 96kHz sample rate. What’s important here isn’t that every card delivers its rated specifications, but that the results are collected in the same way, allowing direct comparison.

Loopback, 24/96 Playback
ASUS Xonar DX
ASUS Xonar D2
Creative X-FI XG Pro
X-Fi + Xonar D2
Freq. Response (dB, multitone) +
+0, -0.02
+0.07, -0.04
+7.75, -13.54
+10.1, -13.31
Noise Level (dBA)
-110.8
-111.5
-93.2
-100.2
Dynamic range, dBA
110.8
111.8
87.7
91.6
Total Harmonic Distortion (THD)
0.0008
0.0004
0.0013
0.0011
Intermodulation Distortion + Noise (%)
0.0011
0.0013
0.852
0.984
Stereo Crosstalk (dB)
-51.9
-98
-32.4
-19
Intermodulation Distortion + Noise (%, sweep)
0.001
0.0011
1.639
0.005
Frequency Response (sweep) +
+0, -0
+0.1, -0
+3.3, -2
+3.4, -2

This test held several surprises. First, I didn’t expect the Xonar DX to hang so closely with the reference-quality Xonar D2 card in this test. And second of all, I didn’t expect the X-Fi XtremeGamer to lag so far behind the other two cards. At first, I thought the X-Fi XtremeGamer’s comparatively poorer performance was due to a dirtier input stage.

So to compare the two cards on more even ground, I installed the Xonar D2 alongside the X-Fi, and used the Xonar D2’s line-input instead of the X-Fi XtremeGamer’s. This made a sizeable improvement, primarily in the area of signal-to-noise ratio and dynamic range, but the X-Fi XtremeGamer still lags far behind either of the ASUS cards. Stereo crosstalk increased, though that may have something to do with the quality of the loopback cable used.

The closeness in measured performance between the two Xonar sound cards was also a surprise, albeit a pleasant one – it trounced the Creative card by a margin of 10dB in signal-to-noise ratio, with 20dB more available dynamic range, and 0.003% less total harmonic distortion. Things looked really one-sided when it came to intermodulation distortion between the two cards, with the Xonar DX having only one-fifth the IMD of the X-Fi XtremeGamer. Also, the XtremeGamer exhibited more variation in frequency response over its range.

Among the high-performing cards tested, the Xonar DX provides performance that’s incredibly close to the more-expensive D2 in our audio testing. Let’s look at some CPU usage comparisons to see how the Xonar DX will impact your PC’s performance.

Performance Testing

So far, we’ve verified that the ASUS Xonar DX sound card offers performance that’s extremely close to the Xonar D2 and D2X cards from ASUS, and outstrips the next best thing in its price category, the Creative X-Fi Fatal1ty XtremeGamer Professional Edition. However, the primary benefit of the X-Fi XtremeGamer that’s touted by Creative Technology is its hardware DSP, which it claims provides ‘faster, smoother frame rates’ (from product box) because it offloads digital signal processing tasks from the CPU.

Whenever a manufacturer makes a claim like this, the onus is upon us in the tech journalism world to verify it. To accomplish this, I’m using RightMark 3DSound 2.3 to load the test PC’s audio subsystem with varying numbers of simultaneous audio ‘voices’ under various processing situations.

However, also in this section, I’ll be testing both cards under a demo in the game Prey (which you may remember from our EAX 5.0 vs DS3D GX 2.0 article), to see whether the processing of DSP functions in software on the host machine will cause a performance hit in an EAX 5.0 game. Frame rate will be logged, to see what’s having an impact, and where.

RightMark 3DSound 2.3

This aging benchmarking tool has some serious stability and repeatability issues, but it’s still the only game in town when it comes to a standardized, purpose-built test of sound card performance with a controlled number of sound sources. All tests were performed at a 44.1kHz sample rate under DirectSound, and were performed multiple times with the best results attained during the testing being reported here for each card.

Remember, RightMark 3DSound’s repeatability issues mean that there may be quite a bit of variability in these tests. If one card seems to perform better than another card by 0.001%, that’s a virtually insignificant difference, and well within the margin of error. Still, the results seem to paint a coherent picture of each card’s capabilities, along the lines of what I’d expect to see in this kind of testing.

The benefit of the Creative Sound Blaster X-Fi XtremeGamer Professional Edition card’s X-Fi audio processor is readily apparent here, with the X-Fi’s CPU utilization staying below 2%, even with 128 concurrent voices under EAX 2.0. The Xonar DX card performs behind the Xonar D2 in CPU utilization, despite the fact that the cards are based on essentially the same audio processor and signal path.

So what’s different here? Most likely, the PLX PCI-Express bridge chip is placing additional load on the CPU here, while the D2 doesn’t require a bridge chip at all, communicating natively across the PCI bus. The 8% CPU utilization figure for the Xonar DX with 128 voices under EAX 2.0 is a bit troubling – that’s nearly 10% utilization of the CPU for audio processing. The X-Fi card only pulled an eighth of that, even under full processing load.

Game Testing: Prey Demo Playback

ASUS’ Xonar DX card also touts its DS3D GX 2.0 driver feature, which promises to deliver EAX-like functionality under EAX 5.0 games. We won’t deal in this article with the question of whether the DS3D GX 2.0 extension set provides an identical sonic experience to Creative’s EAX 5.0, since we’ve already devoted another entire article to the subject, but one other major question that was raised as a result of that article dealt with performance differences under an actual EAX game.

To test this, I used a custom two-minute demo in Human Head’s Prey, which is an EAX 5.0 game. FRAPS was used to monitor FPS performance, and the map used for the demo was the "Keeper’s Fortress" map. The demo playback testing was performed under Windows Vista, to put ASUS’ claims of superior Vista driver support to the test.

 
ASUS Xonar DX
Creative X-Fi XG Pro
Maximum FPS
32
33
Minimum FPS
23
29
Mean FPS
31.07
31.23

When it comes to the average FPS maintained during the two-minute test, the two cards hang together by mere tenths of a frame per second – hardly a noteworthy difference at all. However, the story here is told by the ‘minimum FPS’ figure. At three points during the demo, a new environment is loaded, and it’s at these points that the system lags more – apparently due to the sound card, since nothing else is changed from test to test.

These deep nulls in the graph appeared no matter how many times the test was run, so they’re almost certainly due to the demo sequence itself, and not an external influencing factor, like background programs. So, while the difference in average frame rates was miniscule and virtually inconsequential, Creative’s claim of ‘smoother’ frame rates on their X-Fi cards would appear to hold up.

Now that we’ve covered all the benchmarking bases, let’s move on to some subjective listening impressions, and then my final thoughts.

Listening Tests

As much as performance benchmarks and test data can tell us about how a sound card performs in relationship to the other products out there, some audio performance characteristics can still only be observed in a good old-fashioned sit-n-listen. After all, what really makes the difference is how the card sounds when it’s doing what it was designed to do – playing sound.

Music, movies, and games all present audio electronics with a complex signal, filled with transient information and complex relationships between pitch, timbre, and loudness. That’s why testing with actual music, movie, and gaming program remains the most important way to evaluate audio components.

In testing the ASUS Xonar DX sound card with music, I used content stored in FLAC format, ripped using Exact Audio Copy and played back via the Foobar2000 media player software. Movie material was served directly from DVD via Windows Media Player. All critical music and movie listening was performed under Windows XP, but game testing was conducted under Windows Vista, to ferret out any compatibility issues. Everything was monitored on my reference headphones, which are the extremely capable, resolving Beyerdynamic DT 770 closed-back circumaural headphones.

Music

For testing the Xonar D2 sound card with a complex musical source, I first cued up R.E.M.’s entire Monster album and settled back into my favorite chair, which happens to be the one that’s at my desk. From the electric guitar opening of "What’s the Frequency, Kenneth?", one major strength of the Xonar DX sound card’s performance was readily apparent – it’s ability to deliver musical nuances and subtleties in a way that I just didn’t feel from the X-Fi XtremeGamer when I auditioned it for the EAX 5.0 vs. DS3D GX 2.0 article in late April.

The solo guitar didn’t just have tone and richness, but shape as well, and it seemed nicely centered between the two headphone earcups. When the entire rock ensemble entered, the Xonar DX also demonstrated its ability to offer plenty of drive as well, and natural-sounding tone throughout the entirety of the track.

Later in the disc, on the song "Tongue", the reverberant electric piano solo in the intro was enveloping, and the electric organ also possessed its own reverberance, but a distinctly different one from the piano. Centered in it all, the lead electric guitar was rendered with all the fatness and ‘crunch’ that the recording engineer intended, without sounding as though anything else was added. The Xonar DX shares the D2 and D2X’s ability to preserve complex harmonic structures, without adding extra harmonics that embellish the sound in any way.

On the final track, "You", the Xonar DX kept each instrument nicely separated, even though the bass and lead guitar laid almost perfectly on top of one another. Even though the Xonar D2 and D2X are ASUS’ reference-quality cards, the Xonar DX preserves a large amount of the fidelity of the more expensive Xonar cards, and I wouldn’t hesitate to use this card where the cost of the D2 or D2X are prohibitive.

The Xonar DX’s ability to handle subtle details admirably was also apparent while listening to the second album I used in testing, Bela Fleck and the Flecktones’ Outbound. In the introduction to the song "Hoedown", I could hear Jeff Coffin’s fingers on the saxophone keys as he fingered every note.

When the track really got cooking, the Xonar DX’s dynamic range got a chance to shine, and every powerful kick of the kick drum was taut yet forceful, though without quite the impression of punch and bottomless depth that I got when listening to the Xonar D2 with its higher-quality output stage components. During Victor Wooten’s bass solo, every note through the Fender Jazz Bass’ stereo pickups was discernibly different in volume and attack.

On "Something She Said", Fleck’s banjo sounded full and warm, yet every string’s fingering was still audible, even as the other instruments slowly entered. The singer’s voice was breathy and smooth, though the impression of transparency and clarity wasn’t quite the same that I got when listening on my reference Xonar D2 card. There’s still something to be said for the added expense of the D2 and D2X cards when a true audiophile-quality product is desired.

Movies

To run the ASUS Xonar DX through its paces with a dynamic movie source, I threw in the Mission: Impossible 2 DVD. Since most people will likely want to pair the Xonar DX card with a high-performance home theater system instead of a pair of reference nearfield monitors at their desk, the ability of the Xonar DX to deliver an enthralling performance with movies is just as important.

M:I-2 begins with an exciting plane crash scene, accompanied by music with subterranean synth bass effects. The Xonar DX delivered the bass effects with vibe and depth, and the explosion of the plane into the mountainside was certainly explosive, yet the card’s dynamic range didn’t seem taxed in the slightest.

Throughout the film, I was continually struck by the level of detail I was able to hear in the film’s sound effects, despite the fact that they were often overlaid by a driving musical soundtrack. In the shootout scene set in a futuristic laboratory, the Xonar DX preserved the reverberant soundfield of the space, covered in hard surfaces, as well as the shimmering detail of shattered glass fragments and bullet casings hitting the floor.

When the firing subsided, the card’s vocal reproduction had a chance to shine. Later, when the scene transitioned from a luxury car’s interior to a coastal outdoor scene, the change in background audio effects was immediately noticeable, and nicely detailed. From a part in the Xonar DX’s price category, this is excellent performance.

Gaming

To test the ASUS Xonar DX card in a game, I switched to the Windows Vista partition of my dual-boot machine, and fired up 2K’s BioShock via Steam. I played through the first level, "Welcome to Rapture", and found that while DS3D GX 2.0 produced realistic-sounding environmental reverb effects, the background ambience sounds could be choppy at times, with random points of noise marring the playback.

This wasn’t a problem I ran into under Prey, so it’s likely an issue of the software drivers requiring more work, but it was disconcerting all the same. I noticed something similar when running DS3D GX 2.0-enabled drivers on my reference Xonar D2 card within BioShock.

Looking for better results elsewhere, I turned to ID Software’s Quake 4 demo, another EAX 5.0 game. During the intro cinematic, the low-frequency rumble of a carrier vessel passing by was phenomenally deep, and while voices still sounded recorded, they did seem reasonably realistic.

In the game, I found that the reverberant effects weren’t as pronounced as in BioShock, even after verifying that the "EAX AdvancedHD" setting was indeed enabled, but the performance was noise-free, and when I exited the labyrinth of tunnels I’d entered into as part of the first level, it was clear that the acoustic environment had opened up considerably.

My gunshots seemed to echo off distant landscape features, and it was clear that while in the tunnels, the EAX effects were simply too subtle to notice in close quarters, but they were certainly present in wide-open spaces. I wouldn’t attribute this to the card itself, but to the game’s design.

Lastly, we’ll wrap things up with my final thoughts.

Final Thoughts

From my testing, it’s clear to see that ASUS’ Xonar DX pushes the performance envelope for a value-oriented card, offering most but not all of the performance of the audiophile-quality Xonar D2 and D2X cards – call it Xonar Lite, if you will. ASUS has trimmed the fat from the high-end Xonar cards, making all the right performance tradeoffs to compete in this crowded product category.

The product makes quite a bit of sense for ASUS at this point – after having made their statement with the reference-level Xonar D2 card last September, they’ve fine-tuned the formula to create a product that’s more accessible to consumers who were turned off by the high price of the Xonar D2 and D2X.

There’s no PCI version of the DX card available, which shows that ASUS is willing to lead the way in leaving the aging PCI bus behind for good and pushing the technology transition to PCI-Express at last. It’s my hope that other manufacturers will pay attention and follow ASUS’ lead in transitioning their product lines to PCI-Express as well.

The ASUS Xonar DX performed well in the audio loopback test, as well as in the subjective music and movie listening tests, delivering performance that, while it wasn’t quite on the level of the more expensive Xonar D2 and D2X cards, still proved the Xonar DX a worthy contender in the $100 price category, trouncing the Creative Sound-Blaster X-Fi Fatal1ty XtremeGamer Professional Edition in the loopback test with significantly lower noise levels and distortion.

Home theater enthusiasts will be won over by the Xonar DX’s optical digital output, as well as its wealth of Dolby DSP processing features and low profile design, while music lovers will appreciate its clarity, dynamic range, and low distortion. The card’s software drivers still need some polish, however, as some issues still exist between DS3D GX 2.0 and specific games.

So, who should buy the ASUS Xonar DX? If you’re building a home theater PC, or if you’re simply looking for impressive high-fidelity performance on a real-world budget, and don’t mind that you’re missing the added punch, vibe, and transparency of the Xonar D2 or D2X, then the Xonar DX is a perfect choice for you.

On the other hand, if you’re using your PC as the hub of a home studio, or if you’re looking for the ultimate in audio performance from your sound card, you’ll still be better off with the reference-quality D2 and D2X cards. If gaming is your thing, and you’re concerned about the impact that the Xonar DX may or may not have on your frame rates, you’ll likely be better served by Creative’s X-Fi XtremeGamer cards.

With the ASUS Xonar DX, ASUS ups the ante considerably in the contest for the ultimate bang-for-the-buck PC audio solution for music lovers and home theater enthusiasts. I’m pleased to award the ASUS Xonar DX sound card a Techgage score of 8/10. For the price, it’s tough to beat, and it’s likely to be a major thorn in Creative’s side for some time to come.

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