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ASUS Xonar D2 Ultra Fidelity 7.1 PCI Sound Card
Date: Oct 24, 2007
Author: Jeff Bouton
Introduction and Specification

Claiming to be the best at anything is bold.  From professional athletes to product manufacturers, stating you or your product is the best out there opens things up for closer scrutiny.  Being the best at what you do, or what you make, means near flawless execution.  Regardless of the context, one thing is certain, if you claim you are the best at what you do, you better be prepared to back those statements up.  This is the position ASUS has put themselves in, stating that their latest product is the best of its kind, period.

In this HotHardware showcase we're going to take a look at a new sound card from ASUS called the Xonar D2 Ultra Fidelity 7.1 PCI Surround card.  Although this is the first sound card ASUS has delivered to market, they've come right out stating they feel this is the best sound card currently available.  That's a confident statement, especially considering this is their first sound card release, not to mention the current state of integrated solutions that can rival the performance of some of the best add-in cards out there from the likes of Creative and others.  With that said, we're going to take a complete look at the
Xonar D2 Ultra Fidelity 7.1 PCI Surround Card to see if it really is the best of its kind or if ASUS' claims falls short.

ASUS Xonar D2 Ultra Fidelity 7.1 Sound Card
Features & Specifications

Audio Performance:
Output Signal-to-Noise Ratio (A-Weighted):
118 dB

Input Signal-to-Noise Ratio (A-Weighted):
118 dB

Output THD+N at 1kHz:
0.0004% (-108dB)

Input THD+N at 1kHz:
0.0004% (-108dB)

Frequency Response (-3dB, 24-bit/96kHz input):
<10Hz to 46kHz (for all channels)

Frequency Response (-3dB, 24-bit/192kHz input):
<10Hz to 90kHz (for all channels)

Output/Input Full-Scale Voltage
2 Vrms (5.65 Vp-p)

Sample Rate Conversion Quality:
Almost lossless, high-fidelity floating-point filters, which has:
-140dB THD+N (typical value for 44.1K->48KHz, 24bit)
-145dB Dynamic Range (typical value for 44.1K->48KHz, 24bit)

Main Chipset:
Audio Processor:
ASUS AV200 High-Definition Sound Processor (Max. 192KHz/24bit)

24-bit D-A Converter of Digital Sources:
Burr-Brown PCM1796 *4 (123dB SNR, Max. 192kHz/24bit)

24-bit A-D Converter for Analog Inputs:
Cirrus-Logic CS5381* 1 (120dB SNR, Max. 192kHz/24bit)

Sample Rate and Resolution:
Analog Playback Sample Rate and Resolution:
44.1K/48K/96K/192KHz @ 16/24bit

Analog Recording Sample Rate and Resolution:
44.1K/48K/96K/192KHz @ 16/24bit

S/PDIF Digital Output:
44.1K/48K/96K/192KHz @ 16/24bit ,Dolby Digital, DTS, WMA-Pro

S/PDIF Digital Input:
44.1K/48K/96K/192KHz @ 16/24bit

ASIO 2.0 Driver Support:
44.1K/48K/96K/192KHz @ 16/24bit

I/O Ports:
Analog Output Jack:
3.50mm mini jack *4 (Front/Side/Center-Subwoofer/Back)

Analog Input Jack:
3.50mm mini jack *2 (Line-In/Mic-In)

Other line-level analog input (for CD-IN/TV Tuner):
CD-In, Aux-In (4-pin header on the card)
Digital S/PDIF Output:
Coaxial and High-bandwidth Optical Combo Connector
Supports 192KHz/24bit

Digital S/PDIF Input:
Coaxial and High-bandwidth Optical Combo Connector
Supports 192KHz/24bit

MIDI Ports:
Additional MPU-401 MIDI I/O bracket and converter cable

Driver Features:

Operation System:
Windows Vista/XP(32/64bit)/MCE2005

Dolby® Technologies:
Dolby® Headphone, Dolby® Virtual Speaker, Dolby® Pro-Logic IIx, Dolby® Digital Live

DTS® Technologies:
DTS® Connect (DTS Interactive Encoder and DTS Neo:PC)

Smart Volume Normalizer™:
Normalizes the volume of all audio sources into a constant level

Xear 3D™ Virtual Speaker Shifter:
Virtual 7.1 speaker positioning

Magic Voice™:
Modifies the sound of your voice, for VOIP and online chat applications (Windows XP)

Karaoke Functions:
Music Key-Shifting and Microphone Echo effects (Windows XP)

Professional Bass Management/Enhancement system

Other Effects:
10-band Equalier/27 Environment Effects

3D Sound Engines/APIs:
EAX®2.0&1.0, A3D® 1.0, DirectSound® HW & SW

DirectX 9.0 or above required for 7.1ch output

Bundled Software Utility:

Portable Music Processor utility:
Backup digital music content or CD audio into regular MP3/WMA files with Dolby Headphone, Dolby Virtual Speaker (w/ Pro-Logic II), and Smart Volume Normalization processing (Windows Media Player 10 or above is required)

Professional Audio Editing Utility:
1. Ableton Live Lite
2. Cakewalk Production Plus Pack (SONAR LE, Dimension LE, and Project5 LE)

PowerDVD 7.0:
Software DVD player with Dolby Digital 5.1 decoder

-3.5mm-to-RCA adaptor cable *4 (8ch)
-S/PDIF optical adaptors *2
-S/PDIF optical cable *1
-Additional MIDI card, cable, and external standard MIDI adaptor Y cable *1
-Dolby Demo CD

ASUS Xonar D2 Ultra Fidelity 7.1 Sound Card
The ASUS Xonar D2 Ultra Fidelity 7.1 PCI Surround Sound Card is complemented by a robust retail bundle covering several software titles and an abundant collection of extra cabling.  ASUS includes a total of four 3.5mm-to-RCA adapters for connecting RCA equipment to the Xonar D2 while two pair of SPDIF Optical Adapters are provide along with a single SPDIF Optical Cable.  For MIDI inputs, the Xonar D2 utilizes a MIDI card that connects to the sound card with an external four pin cable.  Additionally, a MIDI Y Adapter is included to marry up to external MIDI components.

On the software side, ASUS includes a CD of "Lite" software titles such as Ableton Live, Sonar LE, Dimension LE, and Project 5 LE.  These titles give the end-user powerful tools for a wide range of audio editing, conversion and mastering functions.  Ableton Live Lite and Sonar LE offer a complete package for music creation, production and playback while Dimension LE and Project5 LE deliver software synthesizer capabilities for complete composing and production of custom audio.   For more details, we suggest visiting the Cakewalk website for a complete breakdown on each program's functionality.  We were pleased to see a fully functional and current copy of PowerDVD 7 included in the package and it was not of the scaled down 2-Ch flavor that has been appearing in many OEM bundles lately.  This version is the 5.1 edition that can be upgraded to full Dolby Digital EX 7.1 Surround Capability.

Rounding out the bundle is a Dolby Headphone Dolby Virtual Speaker Demo DVD and a Drivers CD which includes Windows XP and Vista drivers, Electronic User's Manual, Portable Music Processor and RightMark Audio Analyzer 5.6.


The ASUS Xonar D2 Ultra Fidelity 7.1 PCI Sound Card itself is built around a 24-bit
ASUS AV200 High-Definition Sound Processor that boasts a SNR (Signal-to-Noise Ratio) of 118dB, which is the best SNR we could find, scouring the market for comparable solutions.  The card supports 44.1, 48, 96 and 192KHz sampling with floating point filters claiming near lossless conversion.  The card is also equipped with four Burr-Brown PCM1796 24-bit D-A Converters for digital sources while a single Cirrus-Logic CS5381 24-bit A-D Converter handles analog signal.  The card is encased with an EMI (Electronic Magnetic Interference) shield to ensure surrounding components do not have a negative effect on audio quality.  For added aesthetics, ASUS added illumination to the shield while the rear port collection is also illuminated, making finding the right port a bit easier to locate.

The back end comes with all necessary inputs/outputs to fit virtually any usage scenario imaginable.  The top starts with a MIC and Line-In port followed by Headphone/Front, Side Surround, Center/Sub and Rear outputs.  The last two RCA ports are for SPDIF Input and Output.   The top of the card included three connectors as well, one marries up to the external MIDI card while the second supports direct CD-IN, with the third Aux-In port connecting to a TV-Card or other device.
ASUS Audio Center

The Asus Xonar D2's performance is facilitated by a comprehensive driver package dubbed Asus Audio Center.  This utility unlocks the sound card's wide array of features and settings.  The default Main View provides a graphic spectrum of the current audio playback along with DSP Mode, EQ Mode and Output Device status.  The right panel consists of a volume dial, SVN (Smart Volume Normalization) for maintaining a constant volume level from all sources and Mute controls.  The layout is relatively intuitive and comes with a small learning curve thanks to a comprehensive electronic User's Manual.  Impressive layout aside, we did find the animation of the spectrum meter very laggy, which took away from its overall impact somewhat.

Main View (a)
Main View (b)

The Main menu also has a DSP Mode which consists of four control options at the lower right of the menu.  These Digital Sound Processing modes are pre-configured settings to be used in various playback scenarios.  With either Music, Movie or Game Mode enabled, custom equalizer settings are overridden and automatic adjustments are made to the Virtual Speaker positioning for proper audio positioning and playback.

To access further options, the main menu can be expanded to reveal additional controls.  The most configurable screen of the collection is the main view which offers options for channel setting, sampling rates and the like.  The Audio Channel menu is only available within Microsoft Vista and provides 2, 4, 6, and 8 channel settings that are synchronized with Vista's integrated speak configuration settings, while sampling rates range from 44.1, 44, 96 and 192KHz.  The Analog Out menu sets the speaker configuration for headphone, 2, 4, 5.1 and 7.1 speaker configurations.

 Mixer  Effects

The Mixer screen offers level controls for all available inputs and outputs.  The Effects screen is where the majority of the driver's extra effects reside.  There is a 10-band equalizer with 11 presets and user-defined options.  The drivers also offer environment settings which apply special effects such as Concert Hall, Arena, Underwater and a dozen other choices.  The field size can also be managed from Small, Medium and Large to adjust the over all intensity of each effect.

 Karaoke  FlexBass

The next screen focuses on karaoke functionality, which does a surprisingly good job at removing vocals while maintaining the music's integrity.  The song's pitch can be tweaked and the vocals can we reduced or nearly removed, only audible when the volume is at excessive levels.  The FlexBass option gives greater control over bass signal, offering crossover adjustments from 50HZ to 250HZ, while the speaker size can be adjusted between small and large.
HH Test Setup & RightMark Audio Analyzer 6.0.6

HotHardware's Test Systems

AMD Athlon X2 5200+

(NVIDIA nForce 590 SLI)

Ultra ChillTec Thermo-Electric Cooler

2x2GB OCZ PC-6400

On-Board Ethernet
Realtek HD Audio On-board

ASUS Xonar D2 Ultra Fidelity 7.1 Sound Card

WD1500 "Raptor" HD
(10,000 RPM SATA)

Windows XP Pro SP-2

Testing Methodology:

In testing the performance of the Xonar D2 Ultra Fidelity 7.1 Sound Card, we've taken several approaches.  First, we ran RightMark's Audio Analyzer 6.0.6 to gauge the card's vital statistics, configuring the card as outlined in the instructions provided on RightMark's website specifically for the Xonar D2.  Next, we ran RightMark 3D Sound 2.3 for synthetic gaming performance, from 8 buffers up to 60.  For real world gaming performance, we ran F.E.A.R. with minimum video settings and toggling EAX 2.0 on and off.  In all tests, performance was compared to our test bed's Realtek HD Audio integrated controller as well as an older AudioTrak Prodigy 7.1 Sound Card.  All tests were run at 24-Bit.

Subjective audio testing was done with 70 Watt
Logitech X-530 Series Speakers.

Rightmark Audio Analyzer 6.0.6
Audio Testing
The RMAA suite is designed for testing quality of analog and digital paths of any audio devices, be it a sound card, an MP3 player, a consumer CD/DVD player or an acoustic set. The results are obtained by playing and recording test signals passed through the tested audio path by means of frequency analysis algorithms.

ASUS Xonar D2

Realtek HD Int. Audio

AudioTrak Prodigy 7.1

The Frequency response was tighter with the Xonar D2 when compared to the Realtek integrated sound controller, staying within +.05/-.03 at 44.1 and 48KHz while widening somewhat to +.06/-.04 where as the Realtek HD Audio had wider deviations, most notably at 44.1KHz.  The elder Prodigy 7.1 demonstrated the widest swings in frequency response, while Noise Level and Dyamic Range fell between the Realtek HD Audio and the Xonar 2.  Looking at Noise Levels closer, the Xonar D2 ran at a difference of -18dB compared to the Realtek HD Audio and -13dB compared to the Prodigy 7.1.  Dynamic Range was the mirror image of Noise level, with the Xonar D2 averaging +18dB over the Realtek HD Audio controller and +13dB over the AudioTrak Prodigy.  Total Harmonic Distortion, IMD + Noise and Stereo Crosstalk all favored the Xonar D2 as well. 

Another reference point that you may want to consider are statistics we collected when we reviewed a Soundblaster X-Fi ExtremeMusic sound card.  In that piece we found the X-Fi ExtremeMusic to offer better results with Dynamic Range and Noise levels, however the Xonar D2 had a much tighter Frequency response overall

CPU Utilization with Rightmark 3DSound 2.3 and F.E.A.R.
Rightmark 3DSound 2.1
More Audio Analysis

Rightmark's 3DSound test measures CPU load depending on the DirectSound device mode. The program synthetically emulates the main cycle of a typical ingame sound engine while also performing standard DirectSound diagnostics checks for supported EAX versions.

    Asus Xonar D2                   Realtek Int. HD Audio                AudioTrak Prodigy

8 Buffers

16 Buffers

24 Buffers

60 Buffers

In this test, we varied each test run by the buffer setting, started at 8 buffers and increasing up to a maximum of 60 buffers.  We can see at 8 Buffers, the Xonar D2 had the least amount of CPU activity while the Realtek HD Audio and Prodigy 7.1 were more on par with increased CPU utilization.  At 16 Buffers, the Xonar D2 and Realtek HD were on the same level while the Prodigy experienced less peaks at this level.  This trend continued through the remainder of the various buffer designations, with the Xonar D2 demonstrating the least impact on the CPU in each test.

Performance Comparisons with F.E.A.R.
Details: http://www.whatisfear.com/us/

One of the most highly anticipated titles of 2005 was Monolith's paranormal thriller F.E.A.R. Taking a look at the minimum system requirements, we see that you will need at least a 1.7GHz Pentium 4 with 512MB of system memory and a 64MB graphics card that is a Radeon 9000 or GeForce4 Ti-class or better to adequately run the game. Using the full retail release of the game patched to v1.05, we put the graphics cards in this review through their paces to see how they fared with a popular title. Here, all graphics settings within the game were set to the maximum values, but with soft shadows disabled (soft shadows and anti-aliasing do not work together currently). Benchmark runs were completed at a resolution 640x480x32, with and without EAX 2.0 enabled.

The Realtek HD Audio control barely fluctuated with EAX enabled or disabled, with a mere 1 FPS difference.  With EAX disabled, the Xonar D2 added 9FPS, while enabling EAX resulted in the performance dropping a few frames short of the Realtek controller.  In reality, these are minor fluctuations that should have minimal effect on gameplay regardless of the video settings applied.  The older AudioTrak Prodigy 7.1 had a negative impact on overall frame rates due to it's higher CPU utilization and EAX 2.0 was not supported with this model.  This demonstrates perhaps how those running older sound cards can benefit greatly from the advances in integrated audio or by adding a newer quality sound card to the mix such as the Xonar D2.
Subjective Experience - Audio, DVD, Gaming Quality

For our subjective listening tests, we utilized a set of Logitech X-530 5.1 speakers connected to each sound solution via an analog connection. We ran the system through a variety of different playback scenarios and collected our subjective opinions for each. This is the hardest part of an audio product evaluation  It's very much like food, where each person can eat the same dish yet have their own unique feedback on the experience.  Regardless, we tried in several usage environments below to best illustrate the overall performance of each audio solution and offer up our objective yet subjective opinion.


To assess audio playback we sampled a broad range of music covering the audio spectrum.  We spent several days listening to the likes of John Coltrane and several Latin Jazz collections with lots of distinct highs for sampling.  We then shifted focus on Pearl Jam, Radiohead and Audioslave for rock/alternative while ATB and Tiesto allowed us to sample performance with Trance/Dance tracks.  In each area we covered, the music with the Xonar D2 was full and crisp with no detectable noise or hiss whatsoever.  Whether grooving to Coltrane's Resolution or tripping with Radiohead's Backdrifts, the audio quality didn't disappoint.  ATB's Killer pumped out ample, clean bass while highs remained sharp and clean.  We have to give credit to the Realtek HD Audio which also sounded quite good as well.  Surely those audiophiles with an acute sense for audio quality may pick up on certain nuances better than others, but overall, both the Xonar D2 and Realtek HD Audio playback devices performed well with the Xonar D2 having a mildly noticeable advantage.  The older Prodigy 7.1 was decent as well, but simply did not have the same punch in bass or crisp highs as the newer solutions.  However, we did like its Four Way Clone option that forces the music through all four satellite speakers.

DVD Movie:

For DVD playback, we opted to load several intense battle scenes from Steven Speilberg's Band of Brothers.  The goal was to play scenes with complete chaos to challenge the positioning of the surround sound system.  Whether it was bombs exploding, machine guns firing, gun casings clinking on the ground or armored tanks rolling by, the sound was full, accurate and completely immersive with the Xonar D2.  Once again, the Realtek HD Audio did a decent job as well, but the Xonar D2 certainly offered a more full experience.  The Prodigy 7.1 solution performed OK for a card of its age, however, we did pick up some minor distortion at higher volume levels and the overall experienced seemed a bit flat in comparison to the other two sound solutions.

Game Play

With gaming performance, we opted to focus our time on BioShock, an incredible game with rich storyline, awesome effects and soundtrack.  After spending a few hours playing with the Realtek HD Audio solution, we switched over to the Xonar D2 and immediately felt that the experience was more full and complete.  Positioning of audio was accurate with both solutions, but the experience simply felt more real with the Xonar D2.  We then shifted from 5.1 speakers to headphone gaming using common earbud style headphones and the good vibrations continued.  With the drivers configured for headphones, the Xonar did a superb job of simulating a 3D environment, ensuring the positioning of the audio was accurate for headphone playback.  The Realtek HD Audio seemed more stereo than 5.1 surround, but did a decent job overall.  The Prodigy 7.1 was outclassed altogether here, failing to impress in spatial orientation with both speakers and headphones.

Final Words

Overall performance of the Asus Xonar D2 7.1 Ultra Fidelity Sound Card was quite good.  Both synthetic testing with RightMark Audio Analyzer and RightMark 3D Sound, the vital statistics were good, with the Xonar having a marked advantage, most notably in RMAA.  With gaming performance, CPU utilization was relatively even, with the Xonar D2 dropping below the Realtek HD Audio controller slightly with EAX testing, while the Xonar D2 had a 9 FPS lead with EAX disabled.  In all of our subjective tests, we were quite pleased with the Xonar D2's performance, finding little shortcomings, although the Realtek's integrated HD Audio solution performed rather well too.

The ASUS Xonar D2 Ultra Fidelity 7.1 sound card came with promise of being the best sound card in its class, but best is broad sweaping statment that we'll steer clear of in general.  It’s certainly priced at the upper end of cards in its class but does boast excellent SNR performance.  However, saying it’s the best depends on its intended use from an end user's perspective.  For a prosumer class card, the ASUS Xonar D2 Ultra Fidelity 7.1 Sound Card has a lot to offer, and serious audiophiles may find its feature set robust, with little drawback. 

However, from a average user looking for a solid sound card for music, movies and gaming perspective, the ASUS Xonar D2 Ultra Fidelity 7.1 Sound Card may a bit overkill.  Synthetic performance testing demonstrated the performance and accuracy differences between integrated audio and the Xonar D2 without question.  We just don't see a glaring reason to suggest the average user take the leap from a good integrated sound processing solution to a high quality PCI sound card like the Xonar.  We did note in our subjective segment that the Xonar D2 offered superior performance especially in gaming scenarios, but integrated Realtek HD Audio wasn't too far off the mark versus the Xonar card.  Not to mention that the Realtek solution comes built into a motherboard with minimal CPU utilization or increase in cost.  Where the ASUS Xonar D2 Ultra Fidelity 7.1 Sound Card fits in, is with users looking for a bit more out of their total sound solution.  For any user looking for advanced features and the ability to connect to a broad range of external components, the Asus Xonar D2 and its retail bundle should bring a lot to the table for the audiophile or surround sound
aficionado that can justify the added expense. 

_Very Good Audio Reproduction
_Excellent surround-sound and spatial positioning performance
_Robust Retail Bundle
_Good Gaming Performance
_EMI Shield
_Illuminated Ports
_Stable Drivers
_Limited CPU off-load benefits

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