Creative EAX vs. ASUS DS3D GX 2.0

[PAGETITLE=Introduction, The Story So Far] When we first reviewed ASUS' Xonar D2 sound card in September of last year, 'impressed' didn't begin to describe our initial reaction - quite simply put, it rocked our faces off. Several other Techgage authors quickly picked up cards of their own, and were similarly stunned by the competency, clarity, and fidelity. We were sure that Creative's X-Fi cards had finally met their match, but one gripe that we repeatedly heard from our readers was lack of support for Creative's EAX versions 3.0 and above. EAX, now in version 5.0, is a proprietary Creative Labs technology, but versions 1.0 and 2.0 of the specification were made freely available for use by other manufacturers, a practice that ceased with version 3.0. It was a clever scheme - versions 1 and 2 of EAX were hugely popular, and gamers hoping to take advantage of the technology's newest iteration would have to choose Creative hardware exclusively. So what exactly is EAX? The Environmental Audio eXtensions (EAX) is a proprietary sound API that allows developers to use the onboard digital signal processing capabilities of Creative's audio chips to produce more realistic virtual environments through simulated environmental reverb and occlusion effects. The centerpiece of EAX is hardware-based signal processing, controlled directly through the software itself, which is why we were surprised to learn that ASUS had released a new driver revision for their Xonar cards, enabling "EAX 5.0 Support". We initially assumed that ASUS' driver wizards had come up with a way to mimic the Creative X-Fi's onboard DSP through the driver software itself, in the same way that Dolby and DTS processing are handled. In a sense, we were correct. To finagle the functionality of Creative's EAX 5.0 from the ASUS AV200 (D2, D2X) and AV100 (DX) audio processors (better known as the C-Media CMI8788 OxygenHD chipset), which rely upon software-based DSP, ASUS reworked the DS3D GX extension set to provide all the functionality of Creative's EAX Advanced HD 5.0 through the DirectSound engine itself - in software. That means 128-voice 3D positional audio and environmental reverberation. ASUS admits that this isn't true 'EAX' - rather an emulation of the functionality of EAX 5.0 through the software driver. According to ASUS, the benefit of this approach is that it removes the need for an abstraction layer to provide a direct connection between DirectSound and the audio driver. Windows Vista eliminated the Hardware Abstraction Layer (HAL) of Windows XP and 2000, severing this direct software link between drivers and applications, and leaving owners of Creative X-Fi and Audigy cards without surround sound or EAX effects under Vista. Creative responded to this problem with the ALchemy software upgrade, which mapped DirectSound3D calls to equivalent OpenAL calls. Because OpenAL is third-party software, it was not crippled by the loss of the HAL, and this approach re-enabled the lost functionality. But while this software fix is available to X-Fi owners at no extra charge, Audigy card owners will have to cough up $9.99 simply to download the compatible fix. In addition, not all game titles are supported. ASUS says their Xonar sound cards function without this limitation, even while using EAX functionality. [PAGEBREAK] [PAGETITLE=The Story So Far (Cont'd.)] It wasn't long at all before Creative had something to say about ASUS' claims regarding EAX 5.0 functionality, however, and we soon received an email from Creative Technology's VP of Marketing Communications, Phil O'Shaughnessy, claiming that by mapping EAX reverb functions to their DirectSound3D GX ("Game eXtensions") effects engine, ASUS was not providing a "genuine" EAX experience, and was "misleading" customers by claiming to support EAX 5.0 functionality. What we've gathered from Creative's statement is that the ASUS approach simply allows the Xonar sound card to render 128 simultaneous voices, but it's still limited to the EAX 2.0 effects palette (Environmental reverb and occlusion). Here's a quick breakdown of how the EAX versions compare to one another: EAX 1.0 Environmental Effect Presets. 32 individual 3D voices. Per-channel individual environmental presets. Hardware DSP Rendering. EAX 2.0: Occlusion Effects. Material-specific reverb parameters. EAX 3.0: 'Smoothing' between 3D audio environments. Direct access to all reverb parameters. Environmental Panning. New reverb engine. 64 simultaneous voices. Beginning of the AdvancedHD Designation from new reverb engine. EAX 4.0: Real-time hardware effects. Multiple simultaneous environments. Flange, echo, distortion, and ring modulation effects. EAX 5.0: 128 simultaneous voices. EAX Voice - Processing of microphone input signal. EAX PurePath - EAX Sound effects can originate from one speaker only. Environment FlexiFX - 4 available effects slots per channel. EAX MacroFX - realistic positional effects at close range. Environment Occlusion - Sound from adjacent environments can pass through walls. (Source: Creative) ASUS countered that while their DS3D GX 2.0 engine simply emulates the environmental reverb effects of EAX 5.0 in software, instead of relying upon a dedicated DSP chip, they believe the software-based DSP approach is superior because it can work directly through DirectSound3D, instead of requiring an ALchemy-style solution based on a third-party software API, so it's automatically compatible with all DirectSound3D games under Windows Vista, while ALchemy is only verified to work with a limited number. In addition, though ASUS states that they "respect the capability of a dedicated DSP processor to offload the CPU work", they found that performing the signal processing associated with positional 3D audio in software instead of on dedicated hardware had a minimal impact on overall system performance during gaming, and question the necessity of hardware-accelerated positional audio and environmental effects on modern gaming PCs. In their response to Creative's criticism, ASUS also jabbed at the exclusive nature of Creative EAX, writing that their implementation was not "locked behind specific X-Fi cards", and that software DSP effects such as those provided by DS3D GX 2.0 offered advantages in "flexibility and universally guaranteed user experiences." Taking another look at the above list of EAX versions and their features, however, there are other EAX functions that ASUS does not claim to have matched with the new DS3D GX 2.0 engine. Among them are EAX Environmental Panning, simultaneous environments, flanging, distortion, ring modulation, EAX Voice, and Environment Occlusion. They might be in there (or their equivalents), but we haven't heard. So, to recap: While ASUS support of EAX 5.0 isn't true "EAX" - they haven't licensed anything from Creative - the DirectSound3D GX 2.0 extension set aims to free the positional 3D audio market from Creative's grip by performing the same functions in EAX 5.0-enabled games, without the Vista compatibility issues of hardware-acceleration, and the half-baked ALchemy solution. This article seeks to answer one question - Are you likely to notice a difference between ASUS' DS3D GX 2.0 and Creative's EAX Advanced HD? We've got cards, and we're not afraid to use them... [PAGEBREAK] [PAGETITLE=Testing Methodology and Equipment] Before we begin with my own listening tests, I'd like to toss in a word about exactly how I'll be going about testing this. Some of the most sophisticated instruments for audio testing are right on the sides of your head - your ears have a frequency response that ranges from 20 Hz to 20 kHz, and a dynamic range that spans over 120dB, with a threshold of hearing that begins at about 20dB, depending on how you've abused your ears over the years. Yet, many people don't realize that they can trust their ears just as well as they can trust their eyes or nose. So to test ASUS' claims against Creative's counterclaims, I'll be relying principally on my ears to detect differences in the quality of each card's positional and environmental effects. When we approached Creative with the idea for this article, they happily obliged by sending along a Creative Sound Blaster X-Fi XtremeGamer Fatal1ty Professional card to use in testing. Besides being a real mouthful to say, this card is targeted toward gamers who seek robust audio hardware, but can do without a plethora of accessories. Representing the ASUS side in this battle is the high-end ASUS Xonar D2 sound card, which I reviewed in September of last year, and currently own. Another advantage of ASUS' software-based DSP approach is apparent when considering that all it takes to add the improved DS3D GX 2.0 functionality is a driver upgrade, which I installed on my machine before beginning the testing. By using the higher-quality Xonar D2 instead of the newer but more value-oriented DX model, I'm giving the Xonar side in this fight the best representation it can possibly have against the X-Fi. The Testing Rig CPU: AMD Athlon 64 X2 5200+ 2.6GHz. Motherboard: ABIT KN9 Ultra (NForce 570; MCP-55) Memory: 2 GB OCZ Gold DDR2-1100 @ DDR-800. GPU: ATI Radeon HD 3870, 512MB. Sound Cards: ASUS Xonar D2, Creative Sound Blaster X-Fi XtremeGamer Fatal1ty Professional. PSU: Antec NeoHE 500W. Silent microprocessor-controlled cooling system. Reference Headphones: Beyerdynamic DT 770, "2005" Edition (250 Ohm) All testing for this article was performed using my reference machine, a modest gaming rig that also features a silent cooling system controlled by a programmable microprocessor controller, reducing background noise. In addition, all tests were performed in my quiet room, with no external noise sources active during testing. To monitor the audio system's output, I'm using my reference headphones, the Beyerdynamic DT 770. These stereo headphones fall within the $250 price category, and are highly revealing of any flaws in the source. They aren't surround, but...

Creative EAX vs. ASUS DS3D GX 2.0

Page 117 –