Environmental Effects

EAX Advanced HD

Most likely to be the main selling point for the Audigy will be its advanced (compared to the Live!) audio positioning features. Creative has done some extensive work to make sure that the audio coming out of our speakers is immersive as possible. Naturally, Creative chose to extend its EAX reverb technology in support of these new features.

EAX was never truly a 3D audio effects technology because it functions on preset reverb algorithms. This means the DSP modulates the sound stream and adds in canned fades and echoes in order to simulate a certain environment. Although at times the EAX effects are convincing, EAX itself still did not address the issue of sound placement in space.

When we're walking into a large hall, we can hear the echoes of our footsteps and the voices of people in the surroundings fill up the entire hall. We also hear the direction of those sounds and thanks to interaural intensity, we're also able to estimate how far away the sound source is. With the outdated EAX implementation in Sound Blaster Live! it didn't take long before gamers realized that better solutions were available.

With EAX Advanced HD, Creative has added four new features to the EAX palette:

• EAX Multi-Environment
• EAX Environment Morphing
• EAX Environment Panning
• EAX Environment Reflections

With the acquisition of Aureal's intellectual property close to two years ago, one would have to wonder if Creative has implemented Aureal's technology into the Audigy. Some of the features above have been available in Aureal sound cards long before the release of Audigy.

Multi-Environment

The first of four technologies deals with mixing environments together in such a way that while we're in one environment, we can hear sounds from completely different environments. Let's say we're in a room upstairs and we hear someone speaking from elsewhere in the house. With Audigy, we'll be able to determine if they're speaking from the kitchen or from the bathroom next door, because each room has its distinct acoustic properties and the Audigy can render them simultaneously. In fact the Audigy can render 4 distinct environments, and in this case, we'd be able to hear the differences between 3 different people in three different rooms. The reason why we can only hear up to 3 people is because we're also standing in a room, and count as the fourth environment. The sounds that are coming from the other rooms, are changed once they enter the room we're standing in, and therefore a fourth reverb process is applied. The SB Live! and other current sound cards out there are only capable of 1, if even that.

Environment Morphing

Environment Morphing allows you to travel from one environment inside a game to another environment without having the sounds change abruptly. For example, the way we hear sounds when we're inside our houses change as we move out into the streets. If we're using the Audigy, as we get closer to the door, we'd be able to hear the acoustics from both the inside and outside of the house. If we were using a Live!, we'd hear all the sounds, but only with the effects applied for inside the house. Only when we leave the house would the new environment effect kick in. This was an apparent problem with the Live! in games like Half-Life and Thief 2. While moving around inside the game, the EAX changes could be heard changing very sharply as the environment changed. Climbing out of a sewer would result in an immediate EAX change from hollow metal tube sounds - because we're still in the sewer - to a completely echoless environment.

Creative implemented Environment Morphing to help smooth these garish reverb transactions. EM is even more important because of the Audigy's ability to apply four different environment effects simultaneously.

Environment Panning

Besides being able to hear what environment a sound effect original from, it's also useful to hear what direction that environment is in. With Environment Panning, Audigy enables us to hear exactly what direction the four separate environments are coming from, how far away they are, and can even account for their motion. This is an extremely useful feature to have in a first-person shooter game when you're trying to figure out where your opponent is. With Audigy, you'll be able to hear if he's in back, outside the front, or lurking somewhere in the basement below you.

Environment Reflections

The last of the four EAX AHD features is reflections. While Aureal users were enjoying full reflection effects, SB Live! owners were limited to just EAX reverbs and the generic DS3D system. With Environment Reflections, we're able to finally hear sounds being reflected off of certain mediums. Sounds can now be manipulated according to the objects that enter or leave an environment.

This is similar to reflections used in A3D 2.0 sound cards. The only difference is that Aureal used its own technique called Wavetracing where the sound driver will analyze the geometry of the in-game environment and tailor the audio according to the actual scene. Aureal's method, while undeniably accurate, was difficult to program for in games, and caused a noticeable performance hit due to the extra system traffic. With Environment Reflections, Creative has given developers an easy path to follow, where all they need to do is define the type of material that exists in the environment - the Audigy takes care of the rest.