After Creative Labs devoured Aureal Semiconductor, the question of choosing a gaming sound card had only one answer – SoundBlaster. The software implementations of 3D sound procedures from Sensaura and QSound were inferior in quality (in terms of the frequency and dynamic range of the processed sound) but also put a heavy load on the CPU. But today, when there are two or even four CPUs in each gaming computer, the computing power is not a problem, giving a second chance to software solutions.
The Xonar D2 being based on a processor and driver from C-Media, the engineers took it easy: 3D sound is created by means of C-Media Xear 3D 7.1 Virtual Speaker Shifter technology which specifies the spatial position of 8 virtual speakers. The sound scene is rendered to them using Sensaura CRL3D HRTF 3D positional sound enhancement with multi-drive. 3D sound is down-mixed into stereo using technologies from Dolby Laboratories: the sound of a virtual 5.1 system is emulated on two speakers by means of Dolby Virtual Speaker technology. The same technology for headphones is called Dolby Headphone. You can visit the Dolby website to learn more about these technologies.
Originally, like any other non-Creative product, the Xonar D2 supported a reverberation model compatible only with EAX 2, but ASUS reported support for EAX 3, 4 and even 5 starting from driver version 8.17.30. Thanks to that, you can use OpenAL in Quake 4, for example, although the programmers still have to work on compatibility with other games. Not all applications identify these capabilities. For example, neither the RightMark 3DSound Positioning Accuracy test nor F.E.A.R. permit to enable EAX Advanced HD in the settings, at least in the Windows XP environment. And the card could only pass 3DMark03’s sound test when I disabled the GX feature. By the way, what is GX?
As you know, the DirectX 10 concept doesn’t allow manufacturer-specific extensions. Each DirectX 10-compatible device must support all of the standard features. EAX extensions version 3, 4 and 5 were only supported by SoundBlaster series products – they didn’t comply with the concept and were outlawed as the result. For games to use their specific DirectSound3D extensions in the Windows Vista environment, Creative’s programmers had to implement the substitution of DirectSound procedure calls with calls to their proprietary OpenAL library. Interestingly, a few years ago, the company created an emulator of OpenAL functions via DirectSound to make OpenAL popular among game developers. And now they had to do exactly the opposite.
The programming people from C-Media and ASUS made the same thing for the Xonar D2 calling it DirectSound3D Gaming Extensions. The difference is that DirectSound calls are translated into Xear3D rather than OpenAL, which is emulated by the card, too. The latest version of the driver features the second-generation DS3D GX with a reverberation model that simulates EAX Advanced HD and with the option of applying gaming reverberations to the microphone signal. The substitution of DirectSound calls is now performed in the Windows XP environment, too. On clicking the GX button in the Xonar D2 Audio Center the difference between DirectSound3D Software and DirectSound3D Hardware disappears because in both cases it is the Xear3D sound engine that works. This is necessary for the current implementation of OpenAL which is based on the generic hardware driver of the above-mentioned library for emulating Creative’s OpenAL. We can expect some improvements in OpenAL support in near future because the latest driver contains a file called Cm_Oal.dll which is yet not used in any way.
As you see, it’s all right about the gaming capabilities of the ASUS Xonar card. It supports all the necessary functions and offers options for adjusting the sound to your preferences. You only have to make out how all of this works. Not having a multi-channel speaker system, I limited myself to checking the cards’ ability to create 3D sound in headphones. Well, it is anyway handier to play with headphones because no one around you hears the shooting and shouts and asks you to lower the volume.
I got acquainted with the ASUS Xonar D2 when the demo version of Crysis game was released. So, I’ll begin with this super-hit. Crysis uses a software sound engine FMOD_EX which is independent from DirectSound3D but allows using EAX effects. Strangely enough, there are serious differences in sound between the ASUS Xonar and the Creative X-Fi. It begins right from the first screen where the disc with the Electronic Arts emblem appears with a screech. This screeching is already volumetric on the Xonar as if the disc is hanging in the air right in front of you. The X-Fi “draws” it flat, in your head. In the game proper, with Dolby Headphone and Dolby Pro Logic IIx features enabled, sounds from all directions are combined realistically, creating a natural picture of the ambient world whereas the background music, sounding from nowhere, adds more impressions. A low-flying jet sounds true, provoking an instinctive urge to bend down. Ricocheting bullets and exploding splinters are very realistic, too. At similar settings (CMSS-3D Headphone mode) the SoundBlaster X-Fi sounds absolutely different. After the change of the sound card you can hear more high frequencies but suppressed medium and low frequencies. The X-Fi delivers better high frequencies and reverberations, thus being better at reproducing open spaces, but it doesn’t provide the feeling of presence and drive you get from the Xonar. It seems like there is total silence around the gamer while the life goes on nearby – but the in-game music is reproduced right in your head. This synthetic acoustic accompaniment has a negative effect on your gaming experience, of course. I personally cannot prefer the X-Fi. It is scarier and more exciting to play with the ASUS Xonar. The difference in frame rate between these two cards cannot be caught subjectively. The test in a standard demo with a flyby of the island at the lowest graphics quality settings and maximum sound quality settings produces the following results (frames per second, average/minimum/maximum):
- ASUS Xonar D2 Game mode (Dolby Headphone) 68.09 / 43.53 / 95.93
- Creative X-Fi Elite Pro Game Mode (CMSS-3D Headphone) 69.86 / 44.96 / 103.15
As I already noted, the latest driver from ASUS makes it possible to enable OpenAL in Quake 4. The improved audio engine the game acquired with one of the patches had been available for owners of Audigy 2 and X-Fi cards before, so I was eager to compare the quality of 3D sound in the laboratory-like conditions of the steel passages of Quake 4. Loading a few saves from different levels I was surprised to hear the Xonar D2 being quite competitive against the SoundBlaster X-Fi again! First of all, I noted its superb reproduction of the direction and distance to the sound source. The aural perception was in full agreement with the visuals. It was only when I looked straight at some object that small turns to the left or right would lead to unpleasant jump-like changes in the sound. Under the same conditions the X-Fi positions sound sources behind you more accurately but moves them about more than necessary on small movements of the game character, provoking an aural disorientation. Besides, it proved to have an odd problem with high frequencies – the hiss of steam and flares doesn’t get quieter with distance. It just stops at a certain moment. The X-Fi yields louder reverberations but I wouldn’t call them more natural: the X-Fi sounds better in one situation but the Xonar proves to be more natural in another. The sound of shooting is not as sharp on the Xonar as on the X-Fi but has a curious timbre. The Xonar is better at reproducing explosions. The X-Fi has more detailed high frequencies. Besides reverberations, the X-Fi can realistically calculate the reflection of sound from walls. When the ElevationFilter option is enabled, it can also reproduce the cannonade over the dungeons more naturally and load the CPU less. Still, I would prefer to play Quake 4 with the ASUS Xonar D2 if the latter were stable with the latest version of the driver (8.17.31 RC01 beta). Each time I had to move from one room to another through an opening door there were problems with sound and the game would quit with the error message “The memory could not be read.”
S.T.A.L.K.E.R. is yet another game that uses OpenAL to create a realistic acoustic environment. And this game was merciless to the Creative X-Fi. Added to the above-mentioned inaccuracy about the direction to the sound source was the incorrect reproduction of the distance to it. It is especially conspicuous for high-frequency sounds. For example, the grunting of bandits running at a distance sounds like you are already surrounded and about to be beaten hand to hand. Of course, this spoils your gaming experience. The ASUS Xonar D2 is quite another thing. It provides a fantastically sharp and natural acoustic picture for a complete submersion into the game world. It’s when you are shooting at a sound and always know how many people are alive behind your back. The wind is howling in your ears, the horrible roar from somewhere makes you shudder, and the bullets buzzing and banging against the steel chassis of abandoned cars make you hurry away from the line of fire even if you don’t see the enemy. I’ve never felt such a realism of gameplay, not even in the famous and awards-covered Crysis. There is almost no performance hit from the software processing of 3D sound. Selecting the lowest graphics quality settings, I had the following average frame rate in the demo record of a flyby of one of the game levels:
- ASUS Xonar D2 Game mode (Dolby Headphone) 253 fps
- Creative X-Fi Elite Pro Game Mode (CMSS-3D Headphone) 280 fps
- Audiotrak Prodigy 7.1 (DirectSound3D software) 283 fps
The last game I tested the cards with seems to have been optimized exclusively for the SoundBlaster with its EAX Advanced HD. It doesn’t notice the support of this technology in the ASUS Xonar and its sluggish samples sound well only on the SoundBlaster. No wonder the SoundBlaster is on the winning side. In the test record for measuring the frame rate, it provides more space, a more accurate localization of sounds, and nice reflections of sounds from the walls. Anyway, the ASUS Xonar D2 did quite well in the actual gaming situation, delivering a very realistic acoustic environment. Although the sounds of shots were dull and early reflections could not be heard, it was easier for me to orient in the heat of a battle with sly bots when I installed the Xonar. I didn’t spot an increase in the CPU load while the integrated benchmark produced the following numbers (frames per second, minimum/average/maximum):
- ASUS Xonar D2 Game mode (Dolby Headphone) 98 / 130 / 175
- Creative X-Fi Elite Pro Game Mode (CMSS-3D Headphone) 112 / 145 / 206
Summing up my long experiments with games, I should acknowledge the progress ASUS has made with the driver and the Dolby Headphone technology which is superb for DirectSound3D-supporting games. In every game I have tried it with, this technology provided a more natural interpretation of the gaming environment than Creative’s CMSS. On the other hand, I have to point at the drawbacks of the current implementation of 3D sound: there is no calculation of early reflections, no processing of the vertical position of the sound source, very high intermodulation distortions at high frequencies that make the sound muddy and dull. If C-Media’s programmers get rid of the distortions, ASUS’ Xonar cards will make serious opponents to products from Creative Labs in games.