RightMark 3D Sound
We regularly cover the CPU utilization of integrated audio solutions in our chipset and motherboard reviews, so this time, we've narrowed our focus to positional audio accuracy. RightMark 3D Sound has a handy positioning accuracy test that lets one arbitrarily define a sound's spatial position to see how each audio implementation handles it.

When dealing only with simple positional audio, we didn't observe any differences between the Analog Devices and Realtek codecs. Each appeared to reproduce audio faithfully based on its position relative to the listener, taking both direction and distance into account.

Next, we fired up RightMark 3D Sound's occlusion test, which lets the user observe how sounds interact with a pair of occlusion fields.

RightMark 3D Sound's occlusion test

In the occlusion test, the Analog Devices codec smoothly muffled sounds between the listener and the occlusion fields. The Realtek codec did not, however. It behaved as if the occlusion didn't exist, failing to modify sounds in a discernable way regardless of whether they were in front of or behind the occlusion field.

RightMark 3D Sound's obstruction test

Moving to RightMark's obstruction test, we observed similar behavior from the Realtek codec. It acted as if the obstructions simply weren't there, while the Analog Devices codec modified sounds as they passed behind each obstruction. The difference between the two codecs couldn't have been starker.

RightMark 3D Sound's synthetic tests do a good job of highlighting the Realtek codec's failure to support EAX occlusions and obstructions correctly, but do those features really matter? To find out, we fired up a couple of popular games that support EAX.

Battlefield 2
Battlefield 2 was configured with the game's high-quality hardware audio option. We played through a 16-player game on the Strike at Karkand level.

We fired up Battlefield 2 on our Analog Devices-equipped system first, and didn't encounter any problems with 3D audio. Sounds came from the appropriate directions, faded with distance, and were accurately affected by buildings, fences, and other in-game objects.

The Realtek codec, on the other hand, was a disaster. Sounds seemed to be coming from the right direction, but there were entirely too many at once. Further investigation revealed that in-game objects had little to no impact on in-game audio; tanks located on the other side of buildings—or even the other side of the map—were as loud as they were driving right next to you.

Battlefield 2 occludes sounds over distance to take air absorption into effect, but the Realtek codec didn't seem to be taking that into account at all. Even when out in the open and free from obstructions, sounds didn't correctly fade over distance.

This apparent lack of proper obstruction and occlusion support effectively made Battlefield 2 unplayable with EAX 3D audio on our Realtek-equipped system. You literally hear every sound on the battlefield as if it's right next to you, plunging the player into aureal chaos.

F.E.A.R.
Battlefield 2 is a chaotic multiplayer game with loads of in-game audio, so we scaled things back a little for another test, playing through early levels in single-player FEAR. The game was set to use hardware mixing and EAX 2.0 effects.

Again, we launched the game with our Analog Devices system first, and we failed to encounter any problems along the way. Bracing ourselves for the unplayable chaos we experienced in Battlefield 2, we ran the game on our Realtek-equipped system, and were pleasantly surprised to find a much more subdued environment. Obstructions and occlusions didn't appear to be working correctly—we'd hear sounds through walls and windows that we didn't with our Analog Devices system—but that didn't affect the gameplay to a great degree.

Of course, FEAR is a very different game than Battlefield 2. Plodding through a largely linear single-player level doesn't produce a lot of simultaneous sounds in different locations, especially if audio is triggered by scripts based on the player's physical location.