Remixed audio cards in Windows Vista

Creative has all but dominated the PC sound card market, in no small part thanks to its prowess with hardware-accelerated 3D audio. The EAX positional audio framework born from the SoundBlaster line became the de facto standard for 3D audio in games, giving Creative a distinct advantage over its rivals. Creative licensed EAX, of course, but it kept competitors at version 2.0, limiting them to 32 concurrent 3D voices and standard-definition sampling rates and resolutions. Meanwhile, Creative extended EAX to version 5.0 with support for 128 simultaneous voices and high-definition resolutions and sampling rates.

Despite its positional audio dominance, Creative has faced increased competition of late, largely from sound cards based on C-Media’s Oxygen HD audio chip. Microsoft’s decision to drop hardware acceleration for DirectSound 3D audio in Vista has also posed a challenge to the SoundBlaster monopoly by blunting some of EAX’s appeal. All the while, motherboard makers have diligently worked to improve the quality of onboard audio solutions, creating a perfect storm that has spawned more PC audio choices than we’ve ever seen before.

Interestingly, two of the most recent additions to the sound card ecosystem use existing audio chips. Asus’ new Xonar D2X, for example, is based on a tweaked version of C-Media’s Oxygen HD. More interestingly, it comes with a PCI Express interface, finally providing fodder for the scores of empty PCIe x1 slots that dot the enthusiast landscape. On the other side of the fence we have Auzentech’s X-Fi Prelude, which is the first third-party card to employ Creative’s X-Fi silicon. The Prelude uses a custom board design and upgraded components in an attempt to wring better sound quality from the already impressive X-Fi audio chip.

The Xonar and Prelude both target the high end of the desktop sound card spectrum, so it’s only fitting that we face them off against each other in Windows Vista. Read on to see how they fare in a range of gaming, signal quality, and subjective listening tests.

Vista’s new Universal Audio Architecture

Before we get into the cards, we should discuss how Windows Vista has changed the audio landscape. Vista includes an all-new audio stack, dubbed the Universal Audio Architecture, which Microsoft wrote new from the ground up with an eye toward improving stability. Windows XP’s audio stack ran in kernel mode—the very heart of the OS—making it possible for buggy drivers or other issues to bring down the entire system. In fact, according to 20-year Microsoft veteran Larry Osterman, who worked on the Vista audio engine, “the amount of code that runs in the kernel (coupled with buggy device drivers) causes the audio stack to be one of the leading causes of Windows reliability problems.”

To avoid audio stack-related stability issues, UAA was designed to run in user mode rather than kernel mode, putting it at arm’s length from the core of the operating system. If UAA crashes, either due to buggy drivers or other issues, the rest of the operating system shouldn’t be affected.

An artifact of this new audio stack is the removal of the hardware abstraction layer for DirectSound, distancing the API from a system’s sound card. Without a hardware abstraction layer, DirectSound calculations can’t be offloaded to an audio chip, effectively killing hardware acceleration for DirectSound. Instead, DirectSound landscapes are pieced together within the UAA’s software audio mixer.

The UAA’s lack of a hardware abstraction layer for DirectSound also affects Creative’s Environmental Audio Extensions (EAX). Because it’s an extension of DirectSound 3D, EAX’s access to hardware acceleration has been cut off by the Universal Audio Architecture.

Hardware-accelerated audio isn’t completely out of the question in Vista, though. Third-party APIs like OpenAL, which doesn’t rely on DirectSound, still have direct access to hardware. OpenAL is far less common than DirectSound and Creative’s near-ubiquitous EAX, of course, but it’s starting to see more widespread support. Bioshock, Call of Duty 4, and Quake Wars all support OpenAL, for example.

OpenAL has also been used by Creative to port EAX to Vista. The company has released ALchemy software that effectively serves as a DirectSound wrapper, converting DirectSound calls for EAX to OpenAL calls that can then be handled in hardware by sound cards based on X-Fi and Audigy audio chips. ALchemy is a free download for X-Fi owners, but those equipped with older Audigy cards have to shell out $10 for an Audigy version of the ALchemy package.

Vista’s Universal Audio Architecture hasn’t just affected hardware acceleration for DirectSound. The new stack also enables a number of new features, including automatic port detection, per-application volume control, and a protected audio path that allows for a whole new world of insidious Digital Rights Management schemes.

Comparing the cards

Now that we’ve addressed Vista’s new audio architecture, it’s time to move onto the cards we’ll be looking at today. However, before we dig too deep into specifics of the Xonar D2X and X-Fi Prelude, let’s take a moment to compare a few key specifications.

One of the biggest differences between these cards is the audio chips that they use; the Prelude employs Creative’s X-Fi audio processor, while the Xonar uses a tweaked version of C-Media’s Oxygen HD. We’ve covered both chips in depth before, so I won’t spend too much time dwelling on their capabilities. For a more detailed look at each, I suggest reading our initial review of the X-Fi audio chip and our Oxygen HD sound card comparison.

Asus Xonar D2X Auzentech X-Fi Prelude

Audio chip
C-Media Oxygen HD Creative X-Fi

Digital-to-analog converter
TI Burr Brown PCM1796 AKM AK4396VF

Analog-to-digital converter
Cirrus Logic CS5381 AKM AK5394AVS

Maximum recording quality
24-bit/192kHz 24-bit/96kHz

Maximum playback quality
24-bit/192kHz 24-bit/96kHz (multichannel)
24-bit/192kHz (stereo)

Signal-to-noise rating
118dB 120dB*

Output channels
7.1 7.1

Multichannel digital output
Dolby Digital Live, DTS Dolby Digital Live, DTS**

Interface
PCI Express x1 PCI

Street price


*Auzentech lists 120dB as a “parts spec” but doesn’t give an SNR for the card as a whole

**DTS encoding is scheduled for a Q1 driver release

One of the key differences between the X-Fi and Oxygen HD is their support for 3D positional audio. Like most other audio chips, the Oxygen HD lacks hardware acceleration for DirectSound, and it’s limited to 32 concurrent voices via EAX 2.0. The X-Fi, on the other hand, is capable of offloading up to 128 voices in hardware via EAX Advanced HD 5.0. EAX 5.0 can also handle higher definition sampling rates and resolutions than 2.0, giving the X-Fi a distinct edge. We’ve seen that advantage play out in Windows XP, where cards based on the X-Fi offer higher in-game frame rates than those based on the Oxygen HD.

Rather than focusing on hardware-accelerated positional audio, the Oxygen HD uses its horsepower to drive real-time DTS and Dolby Digital Live encoding. This allows the Xonar to take any multi-channel audio content—be it from a game or media playback application—and output it via a single digital connection rather than a collection of analog cables. You’ll need a compatible receiver or set of digital speakers to take advantage of this capability, though.

The X-Fi audio chip is also capable of outputting DTS multi-channel audio, but it can’t encode on the fly. Without real-time encoding capabilities, the X-Fi is only capable of passing along an existing DTS multi-channel track. That’s fine for DVD movies that include a pre-encoded tracks, but it’s essentially useless for games, which do not.

Auzentech actually makes sound cards based on the Oxygen HD, so they’re familiar with the chip’s real-time encoding capabilities. In fact, they consider those capabilities so important that they’re bringing them to the Prelude. With the latest drivers, the Prelude is capable of encoding Dolby Digital Live in real time. A driver revision that includes DTS encoding capabilities is also due out in the first quarter of this year.

Moving away from multi-channel, note that the Xonar is capable of playing back and recording 24-bit audio at up to 192kHz. The Prelude also supports audio at up to 24 bits, but the card’s sampling rates top out at 96kHz for both multichannel playback and recording. These limitations are inherited from the X-Fi audio chip, whose support for 192kHz sampling rates is restricted to stereo playback. Don’t worry, though; even DVD-Audio tops out at 24 bits and 96kHz for multichannel playback, only supporting 192kHz for stereo playback, which the Prelude can handle.

Asus’ Xonar D2X
PCI Express audio at last

Manufacturer Asus
Model Xonar D2X
Price (Street)
Availability Now

With its fingers in just about every PC component category, it was only a matter of time before Asus entered the sound card market. They’re diving right in with the Xonar, too. Not only does the card target the high end of the desktop sound card market—prime X-Fi territory—but it’s also available in both PCI and PCI Express flavors. We’ll be concentrating on the PCIe Xonar D2X today, but apart from its interface, the PCI-based Xonar D2 is all but identical.

As one might expect from a high-end sound card, the D2X isn’t cheap. It’s currently selling for $190 online, which is roughly double the cost of Creative’s cheapest X-Fi. However, that price tag also puts the Xonar within $10 of Auzentech’s X-Fi Prelude.

The card itself is dominated by an EMI shield designed to reduce interference within the relatively noisy confines of a modern PC. With a subtle speaker motif, it doesn’t look half bad, either. The EMI shield effectively hides most of the card’s components, so there isn’t much to see from here apart from a PCI Express x1 connector and a four-pin floppy power port. The presence of an auxiliary power connector is a little worrying, so we’ll be looking at power consumption a little later in this review.

To get a closer look at the Xonar, we have to remove the EMI shield. Fortunately, all it takes is a screwdriver, and the payoff is well worth it.

Naked, the Xonar gives up a bounty of onboard components and a better view of the card’s internal connectors. Three are provided, one each for CD and auxiliary inputs, and another for the card’s external MIDI bracket. Don’t pay too much attention to the orange semi-circular bits on the card—they’re just diffusers for some onboard LED ground effects.

Interestingly, the card’s audio chip is identified as an Asus AV200 HD Audio Processing Unit. Ignore the name, though. Asus tells us that the AV200 is simply a modified version of C-Media’s Oxygen HD, which is otherwise known as the CMI8788. C-Media has apparently tweaked the chip just for Asus to provide better sound quality. The AV200’s general feature set remains identical to that of the Oxygen HD.

Between the AV200 and the Xonar’s analog output ports sits a set of four TI Burr-Brown PCM1796 DACs—one for each output channel. The DACs can handle 24-bit audio at up to 192kHz and carry a signal-to-noise rating of 123dB. On the analog-to-digital conversion front, the Xonar employs a Cirrus Logic CS5381 that also supports 24-bit/192kHz audio, this time with a 120dB SNR. Overall, Asus rates the Xonar’s signal-to-noise ratio at 118dB.

Continuing our tour through the Xonar’s assortment of component goodness, we have the chip’s TI R4580I operational amplifiers. The card also includes a National Semiconductor LM4562 OPAMP for the front-channel output.

Since the Xonar’s Oxygen HD AV200 audio processor lacks a native PCI Express interface, Asus uses a PLX PEX8111 bridge chip to provide PCIe connectivity. Bridging may not be as elegant as a native implementation, but we’ve seen bridge chips used successfully in graphics cards and hard drives with no ill effects, so there’s nothing to worry about here. Obviously, the PLX chip won’t be present on PCI versions of the Xonar.

Around back, Asus peppers the Xonar’s gold grill with an assortment of ports, including analog front, center, side, and rear channel outputs and microphone and line inputs. You also get coaxial digital S/PDIF input and output ports. And there’s more.

Asus pimps the port cluster with multicolored LEDs that backlight each port with the appropriate color. The result is an almost unholy combination of gangsta and geek that marries the gaudiest trends associated with each. At first, I was tempted to write off the bling as another useless cosmetic treatment. However, after having to contort myself awkwardly among the dust bunnies and a tangled web of cables under my desk to connect speakers to a sound card because I couldn’t see which ports were which from above, the Xonar’s back-lit ports started to make a lot of sense. There’s no need to worry about the piercing radiance of LEDs, either. Since the port cluster resides at the rear of the system, the LEDs only end up giving off a gentle, unobtrusive glow.

Finished with the Xonar’s hardware, we’re left to dig around in the box, where there’s actually plenty to find. Asus bundles loads of goodies with the card, including a whopping four 3.5mm-to-RCA cables—one for each of the card’s output channels. Also included is a TOS-Link S/PDIF cable and an external MIDI bracket with all the necessary connectors.

As if the array of cables weren’t enough, Asus also throws in a number of software titles, including a music conversion utility that can convert tracks for playback with Dolby Headphone or Virtual Speaker, Ableton Live 6 Lite, PowerDVD 7.0, and a Cakewalk package that includes limited versions of SONAR, Dimension, and Project 5.

Auzentech’s X-Fi Prelude 7.1
Creative, covered

Manufacturer Auzentech
Model X-Fi Prelude 7.1
Price (Street)
Availability Soon

Creative has been able to dominate the sound card market in part because its audio processors—be they Audigys or X-Fis—have offered features and capabilities unmatched by the competition. Those audio chips have only been available on Creative’s own sound cards, giving users who want hardware acceleration for positional 3D audio or support for EAX levels beyond 2.0 little choice in the market.

That is, until now.

Auzentech’s new X-Fi Prelude takes Creative’s best asset, its X-Fi audio processor, and deploys it on a new board design that’s been tweaked to improve overall output quality. What we have, then, is an X-Fi remix—one that comes with a couple of bonus tracks in the form of real-time Dolby Digital Live encoding capabilities available now and DTS encoding that’s promised in a first-quarter driver update.

The fact that Auzentech is working to expand the Prelude’s feature set beyond the X-Fi’s native capabilities easily sets this card apart from X-Fi models already available from Creative, and that’s without even looking at the board itself. At the hardware level, the Prelude is a very different beast from anything in Creative’s stable.

When pictured with an X-Fi XtremeMusic (right), the Prelude’s redesigned board is immediately apparent. The layouts are very different, and so are the onboard components used to bring everything together. In particular, note the Prelude’s use of solid-state capacitors throughout. The XtremeMusic, on the other hand, uses standard electrolytic caps that can have a shorter lifespan.

An X-Fi audio processor sits at the heart of the Prelude, seen above covered by a simple heatsink that looks like it’s been pulled off a 486. With a claimed 10,000 MIPS of processing power distributed across an innovative ring architecture, the X-Fi is easily the most complex and advanced consumer audio processor on the market. Here, we see it paired with 64MB of memory—known as X-RAM—that can, among other things, be used to cache uncompressed audio so that it doesn’t have to be decoded in real time.

Once the X-Fi is finished with an audio stream, it’s passed along to the Prelude’s array of AKM AK4396 stereo DACs. Four of these chips cover the card’s eight output channels, delivering support for 24-bit/192kHz audio with a SNR of 120dB. Playback is capped at 96kHz for multichannel playback, but that’s a limitation of the X-Fi and not the AKM DACs. Converting in the opposite direction, from analog to digital, we have an AKM AK5394AVS ADC. Like the card’s DACs, this two-channel chip can handle 24-bit/192kHz audio, this time with a 123dB SNR. Again, keep in mind that the X-Fi is only capable of recording at up to 96kHz.

One of the more unique features of the X-Fi Prelude, and a staple of Auzentech’s high-end sound cards, is the ability to remove and replace operational amplifiers. In this case, you’re limited to replacing a single OPAMP—National Semiconductor’s LM4562NA—which sits in a socket connected to the card’s front channel output. Amplification for the card’s other output channels is handled by an array of Texas Instruments OPA2134 OPAMPs that are soldered to the board and cannot be easily replaced.

Moving to the Prelude’s port array, we find a standard complement of analog and digital inputs and outputs. No fancy colors here, just a faux-gold finish that requires that you actually read the tiny print associated with each port to figure out what it is. At least there’s a little color coding with the coaxial S/PDIF ports, which have hints of black and grey for input and output channels, respectively.

To complete the S/PDIF equation, Auzentech includes quite a fancy optical cable with adapters that make it compatible with both coaxial and TOS-Link connections. This cable is much nicer and longer than the one you get with the Xonar. However, it’s the only cable that comes in the box.

Auzentech doesn’t offer many perks on the software front either. A driver CD is all you get, and it doesn’t contain much beyond the drivers themselves. A sound card doesn’t necessarily need to be bundled with applications, but it would’ve been nice to get DVD-Audio playback software in the box.

Dissecting the drivers

With Asus and Auzentech spinning unique sound cards based on the Oxygen HD and X-Fi audio processors, it’s only fitting that the drivers for each get a little remixing, as well. Auzentech has arguably done the least on this front, repackaging Creative’s existing X-Fi drivers without so much as changing the skin on the interface. But that’s not necessarily a bad thing.

The X-Fi game mode console

Creative’s audio console is excellent, coming in three flavors for game, entertainment, and audio creation modes. Each offers a unique mix of features and settings to manipulate, dedicating the X-Fi’s formidable hardware resources accordingly. Users can switch between these modes on the fly, as well.

Entertainment mode on the X-Fi

Audio creation mode gets really crazy

Of course, Creative’s drivers have often been accused of being bloated—and fairly so. That isn’t a problem for the Prelude, though. Auzentech’s repackaged X-Fi drivers cut out most of the fat and even include a base driver-only install that ditches the fancy audio consoles in favor of a much simpler interface.

The base X-Fi interface

In an attempt to provide a streamlined driver package for enthusiasts, Auzentech may have cut a little too far. We don’t miss the bloat, really, just the Creative DVD-Audio playback software that’s a part of the standard X-Fi (and even Audigy2) install package. For a sound card capable of playing back high-definition audio, DVD-Audio is a no-brainer, and Creative’s player appears to have been left on the cutting room floor.

One extra that Auzentech has included is Creative’s ALchemy software for translating EAX calls to OpenAL commands that can be accelerated in hardware under Windows Vista. ALchemy is hardly a silver bullet for EAX in Vista, though. The current list of supported games is distinctly lacking in new titles. F.E.A.R. appears to be the most current, and the vast majority are several years old at least. Even Battlefield 2, an older game that was a poster child for the X-Fi’s EAX 5.0 Advanced HD hardware acceleration, is absent from the list. At least in its current form, ALchemy’s benefits appear to be confined to games you might find in the bargain bin, if they’re even for sale at all anymore.

Asus also does some driver repackaging for the Xonar D2X, but this includes a major facelift. The entire driver interface is unique to the Xonar, consolidating control over everything from equalizers, speaker configuration utilities, and virtualization schemes into a single control panel. As with the X-Fi, the drivers can be switched between modes covering audio creation, multimedia playback, and gaming, but the actual interface doesn’t change. Asus also has its own spin on ALchemy called D3D GX.

Available with the latest Xonar drivers, D3D GX is another DirectSound wrapper with full support for EAX. Well, EAX versions 1 and 2, at least—that’s as far as the Xonar goes. Like ALchemy, D3D GX’s list of supported games is dominated by older titles. There are a few odd additions, as well, such as Quake 4, which already has native support for OpenAL. Either way, the Xonar’s lack of hardware acceleration for 3D audio, combined with its support for only the most basic EAX levels, blunts much of D3D GX’s appeal.

Apart from D3D GX, the Xonar’s drivers don’t include much in the way of extras. Features like real-time DDL and DTS encoding are already built into the Oxygen HD, so there isn’t much that really needs to be added. Asus has included some fancy echo cancellation that Skype users should appreciate, though; it works quite nicely.

Our testing methods

Today the Xonar D2X and X-Fi Prelude will face off against not only each other, but a couple of other audio solutions we’ve thrown into the mix. To see how the Prelude stacks up against Creative’s own X-RAM-equipped X-Fi, we’ve thrown an X-Fi Fatal1ty into the mix. Integrated motherboard audio is also represented by Gigabyte’s GA-P35-DQ6, which features Realtek’s ALC889A codec chip.

All tests were run three times, and their results were averaged.

Processor

Intel Core 2 Duo E6700 2.67GHz
System bus 1066MHz (266MHz
quad-pumped)

Motherboard


Gigabyte GA-P35-DQ6
Bios revision F6

North bridge
Intel P35

South bridge
Intel ICH9R
Chipset drivers Chipset 8.3.1.1009
AHCI 7.8.0.1012
Memory size

2GB (2 DIMMs)


Memory type

Corsair
TWIN2X2048-8500C5 DDR2 SDRAM
at 800MHz
CAS latency
(CL)
5
RAS to CAS
delay (tRCD)
4
RAS precharge
(tRP)
4
Cycle time
(tRAS)
12

Audio codec
Integrated
ICH9R/ALC889A with 1.82 drivers
Creative X-Fi Fatal1ty with
2.15.004 drivers

Asus Xonar D2X
with 81724_RC01 drivers

Auzentech X-Fi Prelude
with RC4 drivers
Graphics

GeForce 8800 GTS 640MB PCI-E
with ForceWare 169.21 drivers
Hard drive

Western Raptor WD1500ADFD 150GB
OS

Windows Vista Ultimate x86
OS updates
KB936710, KB938194, KB938979, KB940105

Thanks to Corsair for providing us with memory for our testing. 2GB of RAM seems to be the new standard for most folks, and Corsair hooked us up with some of its 1GB DIMMs for testing.

All of our test systems were powered by OCZ GameXStream 700W power supply units. Thanks to OCZ for providing these units for our use in testing.

Finally, we’d like to thank Western Digital for sending Raptor WD1500ADFD hard drives for our test rigs. The Raptor’s still the fastest all-around drive on the market, and the only 10K-RPM Serial ATA drive you can buy.

We used the following versions of our test applications:

The test systems’ Windows desktop was set at 1280×1024 in 32-bit color at an 85Hz screen refresh rate. Vertical refresh sync (vsync) was disabled for all tests.

All the tests and methods we employed are publicly available and reproducible. If you have questions about our methods, hit our forums to talk with us about them.

Game performance

We’ll kick things off with a selection of four of the most recent PC games on the market, each based on an entirely different engine. All games were tested with FRAPs, which logged frame rates as we played through 60-second sections of each title. Tests were run five times and the results averaged. We’ve also provided a look at how frame rates tracked through our 60-second gameplay run and the median low frame rate for each card.

Bioshock

Bioshock uses Unreal technology, delivering native support for OpenAL in Windows Vista.

Not much to see here, folks. The Prelude technically manages the highest average frame rates of the bunch, but by less than half a frame per second. Only just over one FPS separates the best score from the worst here, and even the median low frame rates are close.

Call of Duty 4

Call of Duty 4 uses an engine of developer Infinity Ward’s own creation. In Windows Vista, audio is handled by OpenAL.

We see a little more difference between in-game frame rates in Call of Duty 4, with the most notable outlier being the X-Fi Fatal1ty trailing the rest of the pack by a few frames per second. Again, the X-Fi Prelude manages to come out on top, although the Xonar and Realtek onboard audio do offer slightly higher median low frame rates.

Crysis

Crytek’s latest engine is an absolute beast, and rather than relying on any form of hardware acceleration, it includes a software audio mixer designed to deliver the same listening experience regardless of the user’s sound card. Unfortunately, FRAPs refused to cooperate with a couple of our configurations—even after a clean reinstall—limiting us to only a couple of test runs with the Xonar and Prelude.

As one might expect, scores are close again. This time, it’s the Xonar taking top honors, followed by dueling X-Fis ahead of our onboard audio implementation. The Prelude’s median low frame rate is a little off the pace here, but overall, we have another wash.

Quake Wars

id Software has long supported cross-platform APIs like OpenGL, so it’s no surprise that Quake Wars uses OpenAL under Windows Vista.

Again, there isn’t a whole lot of difference between the cards. Average frame rates are all within a couple of frames per second. The X-Fi Fatal1ty and Xonar D2X do exhibit notably lower minimum frame rates than the others, though.

Windows XP CPU utilization

Since many enthusiasts have balked at moving to Windows Vista, we threw the cards through a quick round of CPU utilization tests in Windows XP. Here, we can enjoy the full benefits of DirectSound hardware acceleration without Vista’s Universal Audio Architecture getting in the way.

Even with 2D audio, the benefits of hardware acceleration are immediately apparent. The X-Fi cards register the lowest CPU utilization of the lot, and even the Realtek onboard audio uses fewer CPU cycles than the Xonar.

Throw 3D audio into the mix, and the X-Fi cards continue to consume much fewer CPU resources than the competition. The ALC889A is a little closer to the Xonar here, but it’s still more efficient than Asus’ swankiest sound card. At least the Xonar registers support for more than 32 concurrent 3D voices; the ALC889A does not.

The picture doesn’t change much when we add EAX to the equation; the X-Fi-based solutions still dominate, leaving the Xonar in their dust. Even when processing 128 simultaneous 3D voices, the X-Fi cards still use fewer CPU cycles than the Xonar does when handling just 32.

Power consumption

Power consumption has become a staple of our hardware coverage here at TR, but it’s not something we normally tackle with sound cards. However, the Xonar’s auxiliary power connector had us worried, so we busted out a Watts Up? Pro power meter and measured total system power consumption, sans monitor and speakers, at the wall outlet. Systems were tested at idle and again while playing an MP3.

Phew. The Xonar may require a four-pin floppy power connector, but it consumes about as much power as the X-Fi Prelude. The Fatal1ty card pulls slightly less juice, but when compared with the same system running its integrated audio, the power draw of our discrete sound cards amounts to less than 10 watts.

Listening tests

For most users, the most important attribute of an audio card is how it sounds. To test that, I called in some favors with a few friends, bribing them with beer and sushi and subjecting them to several hours of music playback and gaming listening tests in the Benchmarking Sweatshop. These were blind tests, with the listeners unaware of which card they were listening to at any given time. Our test system’s onboard Realtek audio was also left out of this round—we’ve done listening tests with several onboard audio implementations for other articles, and our time was limited. A “free” onboard audio solution like the ALC889A isn’t really a direct competitor to sound cards costing close to $200, anyway.

To highlight the differences between cards, 30-second song clips were played back-to-back on different configurations using Abit’s iDome speakers connected via analog output. Our trio of cards gave us three back-to-back tests per configuration, ensuring that each card went head-to-head with the others. The order of playback was randomized for each test.

This first set of listening tests examines CD-quality audio playback. We used uncompressed WAV audio ripped directly from source CDs and played them back in Windows Media Player 10. Below, you’ll find a summary of our listeners’ impressions of how the X-Fi Fatal1ty, X-Fi Prelude, and Xonar compare. I’ve also injected a few thoughts of my own, although since I was running the tests, I knew which cards we were hearing.

Before getting started, I should note that this is the most difficult set of listening tests we’ve run. Not only were we dealing with a couple of cards based on the same audio chip, but also with high-end cards in the same price range. The differences between them were minor at best, and often indistinguishable, although individual listeners were largely consistent in terms of which cards they preferred.

Battles – Race Out

Imagine, if you will, jazz-inspired electronic music performed by an army of munchkins hopped up on more drugs than Lindsay Lohan in her prime. That’s perhaps the best way to describe Battles, whose Race Out bounces bare, clean drums and guitars back and forth off each other.

With this track, our listeners preferred the Xonar over both X-Fis. The Xonar, they said, produced cleaner sound with slightly less distortion than the Fatal1ty and better drumming than the Prelude. Between the X-Fis, listeners preferred the Prelude for its more distinct drum and xylophone reproduction.

Muse – City of Delusion

The British know how to rock out, and Muse’s City of Delusion is a perfect example. Soaring vocal wails punctuate a track layered thick with loud guitar riffs, violent drumming, and even a little background string action.

Listeners were split on City of Delusion, with one favoring the Xonar over the Prelude for its slightly better background instrumentals and two siding with the Prelude because it didn’t wash the high end of the spectrum together as much as the Xonar. Our listeners were largely in agreement that the Xonar and Prelude both sounded better than the Fatal1ty. In particular, they found Creative’s X-Fi a little tinny. For me, the Xonar came out on top here because it seemed to do a better job of reproducing the strain in the track’s wailing vocals.

Nine Inch Nails – Another Version of the Truth (Kronos Quartet and Enrique Gonzales Muller)

Originally written by Nine Inch Nails frontman Trent Reznor, this rendition of Another Version of the Truth taps the Kronos Quartet for a little classical meets industrial. This string-dominated track uses finer highlights to bring a haunting, almost dissonant cello to a
beautiful climax.

Two of three listeners preferred the Prelude over the Xonar here, claiming that the card offered a slightly richer, warmer sound than either the Xonar or the Fatal1ty. They all had a hard time distinguishing between the cards, though, and I did as well, even knowing which was which.

Tom Waits – Bottom of the World

Tom Waits’ rough, raspy warble sounds a little like what would happen if Bob Dylan smoked a dozen cigars a day for a decade or two and then sang. The result isn’t pretty, but it’s filled with subtle character that gives Bottom of the World a unique depth of depression.

Our listeners were split here, with two preferring how Waits’ harsh vocals really came through on the Prelude. Even the Fatalt1y offered better vocal reproduction than the Xonar, they said. Between the X-Fis, all our listeners preferred the Prelude, claiming it did a better job highlighting background instrumentals that were slightly less audible with the Fatal1ty. My ears concurred, and I also found the Xonar’s background instrumentation to be excellent, albeit at the expense of Waits’ grumbling.

Tori Amos – Raspberry Swirl

Tori Amos’ sultry voice pours over a pounding piano and bass line in Raspberry Swirl, delivering an intoxicatingly seductive aural lapdance to our listeners—the perfect antidote to their Tom Waits-induced depression.

The Xonar was our listeners’ favorite with Raspberry Swirl, particularly as various elements started to compete for center stage as the track got louder. Our panel felt that the Xonar did a better job of balancing the vocals with more subtle background instrumentation. On the Prelude, they heard great vocals and plenty of punch at the high end of the spectrum, but less in the way of background content. Much of the same was reported with the Fatal1ty, which all three agreed sounded marginally less balanced than the Prelude. I thought the Prelude sounded a little better than the Fatal1ty, as well, particularly during the track’s most frantic segments.

Game time: Call of Duty 4

To see if our listeners could detect any difference in sound quality while playing a game, we sat them in front of Call of Duty 4 and had them play several back-to-back rounds on each sound card. For this test, the cards were hooked up to a set of six-channel Logitech Z-680 speakers using analog outputs.

Interestingly, none of our listeners reported any differences in audio playback quality in Call of Duty 4. They did comment that concentrating on playback quality was difficult when trying to stay alive in a firefight, but I observed the entire test session and couldn’t detect any meaningful differences in audio quality or positional accuracy, either.

RightMark Audio Analyzer – Loopback – 16-bit/44.1kHz

Moving from subjective listening tests to something more objective, we used RightMark Audio Analyzer to evaluate output quality. Our first set of RMAA results are from “loopback” tests that route a sound card’s output through its line input. We’ll kick things off with 16-bit/44.1kHz CD-quality audio.

To keep things simple, I’ve translated RightMark’s word-based quality scale to numbers. Higher scores reflect better audio quality, and the scale tops out at 6, which corresponds to an “Excellent” rating.

The Xonar runs the table here, delivering better signal quality across the board. Even its overall score is two points higher than that of the Prelude, and the gaps are huge in several tests. We’ll be providing more detailed RMAA results in a moment.

RightMark Audio Analyzer – Loopback – 24-bit/48kHz

My Nine Inch Nails With Teeth dual disc’s DVD-Audio tracks are 24-bit/48kHz, and we ran RMAA at that bitrate and resolution.

The Prelude bounces back here, outclassing the Fatal1ty in a couple of tests. But the Xonar still reigns supreme, only stooping as low as to tie the Prelude in a handful of tests.

RightMark Audio Analyzer – Loopback – 24-bit/96kHz

24-bit/96kHz is as good as multi-channel DVD-Audio gets, so we’ll test at this bitrate and resolution, too.

Again, the Xonar finds itself at the front of the pack, trailed by the X-Fi Prelude.

RightMark Audio Analyzer – Playback – 16-bit/44.1kHz

To remove each sound card’s line input as a variable, we switched from RMAA loopback to straight playback tests using an X-Fi XtremeMusic installed on a separate system for recording.

Asus continues to dominate our RMAA results, as the Xonar again finds itself atop the heap with CD-quality audio. In these tests, the Prelude fails to distance itself from the Fatal1ty, as well.

RightMark Audio Analyzer – Playback – 24-bit/48kHz

Scores are very close here, with the Xonar locked in a three-way tie with the X-Fis. Only our integrated ALC889A falters, and then only in a couple of tests.

RightMark Audio Analyzer – Playback – 24-bit/96kHz

The Xonar manages to edge out the Prelude in RMAA’s total harmonic distortion test, but that’s its only real advantage over the Auzentech card. The Prelude does score a win over the Fatal1ty in the frequency response test, though.

Detailed RMAA results – Loopback – 16-bit/44.1kHz

If you want to geek out over a bunch of detailed RMAA graphs, we’ve provided the raw results for all of our RMAA tests over the following six pages. These results are included as a bonus; feel free to skip to the conclusion, if you wish.

Stereo Crosstalk

Dynamic Range

Frequency Response

Intermodulation Distortion

Noise Levels

Total Harmonic Distortion

Detailed RMAA results – Loopback – 24-bit/48kHz

Stereo Crosstalk

Dynamic Range

Frequency Response

Intermodulation Distortion

Noise Levels

Total Harmonic Distortion

Detailed RMAA results – Loopback – 24-bit/96kHz

Stereo Crosstalk

Dynamic Range

Frequency Response

Intermodulation Distortion

Noise Levels

Total Harmonic Distortion

Detailed RMAA results – Playback – 16-bit/44.1kHz

Stereo Crosstalk

Dynamic Range

Frequency Response

Intermodulation Distortion

Noise Levels

Total Harmonic Distortion

Detailed RMAA results – Playback – 24-bit/48kHz

Stereo Crosstalk

Dynamic Range

Frequency Response

Intermodulation Distortion

Noise Levels

Total Harmonic Distortion

Detailed RMAA results – Playback – 24-bit/96kHz

Stereo Crosstalk

Dynamic Range

Frequency Response

Intermodulation Distortion

Noise Levels

Total Harmonic Distortion

Conclusions

The X-Fi Prelude and Xonar D2X are both very good sound cards. They offer equivalent gaming performance in Windows Vista with the latest games, and our listeners had a hard time distinguishing between them in our blind listening tests. You’d do well with either of them in your system, really, but a few key differences make one more appropriate than the other, depending on your needs.

Take the X-Fi Prelude, for example. Much of this card’s appeal lies with the X-Fi audio processor it has under the hood—a chip equipped with the most comprehensive support for hardware-accelerated EAX audio around. But that’s largely a moot point in Windows Vista unless you’re playing older games supported by Creative’s ALchemy software, confining much of the Prelude’s allure to those running Windows XP. Fortunately for Auzentech, it seems that many gamers and enthusiasts have little desire to give up XP in favor of Vista.

Were I primarily gaming in Windows XP, I’d take the Prelude over the Xonar in a heartbeat. The Prelude would probably win out over Creative’s own X-Fi models, too, despite the fact that it costs twice as much as the cheapest X-Fi you can buy. Why pay so much more? Because the Prelude does sound a little better, and RightMark confirms that it has higher analog output quality than the X-Fi Fatal1ty. You also get a upgradeable OPAMP, and more importantly, support for real-time Dolby Digital Live encoding that isn’t available with any other X-Fi. With DTS encoding on tap for a driver release this quarter, Auzentech has done well to differentiate the Prelude from Creative’s own offerings, building a premium X-Fi in the process—one that still needs some bundled DVD-Audio playback software, mind you, but the Prelude is good enough to earn our TR Recommended award.

What of the Xonar, then? I’m glad you asked. If you’re running Windows Vista, which largely eliminates the X-Fi’s EAX advantage, the Xonar is the card you want. The Xonar is the better option if game performance isn’t a priority, as well, since the lack of hardware acceleration for positional 3D audio is really the Xonar’s only weakness.

Asus Xonar D2X
January 2008

Otherwise, Asus has done a fantastic job with the card. No doubt thanks to meticulous board design and carefully selected components, the D2X delivered the best RightMark Audio Analyzer scores we’ve ever seen. Couple that with a strong performance in our listening tests and thoughtful little touches like the back-lit port array and generous bundle of extras included in the box, and the Xonar really starts to grow on you. Game performance isn’t bad either, at least in Vista. And then there’s the PCI Express interface, which finally gives enthusiasts something worthwhile to put in their motherboards’ PCIe x1 slots.

When taken with its strong overall performance, the sum of the Xonar’s little perks is enough to elevate it to Editor’s Choice distinction. With cards like these, Asus and Auzentech might just make the PC audio market interesting again.

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