EAX vs. A3D

The Rumble

Kenn gave a pretty simple explanation of EAX and A3D in his Sound Blaster Live! vs. Monster Sound MX300 comparison:
Creative's own Environmental Audio Extensions, or EAX for short, is a reverb engine, capable of manipulating sounds in real-time to conform to set EAX environments, which the developer can either choose from a library or tweak themselves. Creative provides a number of options for customizing reverberated sounds, such as Early Reflection Level, Late Reverb Level, Diffusion, Density, Detuning Rate and Depth, High Frequency Cutoff, and so forth, basically mimicking most of the real-time-calculated functions in A3D 2.0 that make it so cool. A developer basically applies EAX effects to areas, walls, specific sounds, etc. It's easy to implement, and it works well across applications.

Aureal decided to take the hard approach, under the premise that we all live in a dynamic world and preset sound filters couldn't effectively convey realism. Basically, what A3D 2.0 does is look at your position in the level, determine what kind of material the walls are, and renders in real-time the first reflection path of any sound you're capable of hearing. The major benefit of this is that supposedly, as you move around the level the sounds around you change drastically; reflections careen off of different walls at different angles and distances as you move, and the human ear can either consciously or subconsciously pick up on these changes.

What's the big deal?

Okay, I'll have to admit that the whole 3D sound debate between EAX and A3D hasn't been at all important to me. You'll only catch me playing one game at the office: Q3test. I'm willing to sacrifice realism for a deathmatch advantage any day. From our Half-Life tests, we've found that although A3D creates more realistic 3D sound effects but, those same effects make deathmatch more difficult when the 3D engine muffles or distorts a sound while a normal sound card would just play the sound at normal volume.

I'd rather run around with an Sound Blaster AWE 64 and hear everything instead of using a 3D sound card to listen to realistic, mind-blowing effects that'll get me fragged when a brick wall prevents me from hearing Dennis picking up items in the other room. A3D also eats up more precious CPU time because the sound engine needs the processor to feed it the room geometry for the dynamic real-time wave tracing. Of course, deathmatch and frame rate isn't everything, and normal gamers that aren't addicted to deathmatch will appreciate A3D's wave tracing technology. For single player games, A3D 2.0 is great for creating realistic, immersive environments

.