One step in accurately modeling sound is to take into account its distance of origination. DirectSound 3D attempts to do this with three "distance zones" in which sound can be reproduced. By adding reverberation or reducing high frequency response, sound appears to be further away (making sound intensity easy to model on a 1/R^n basis). However, sound in close proximity to the head is more difficult to accurately simulate within the 1m HRTF defined by DirectSound 3D. For objects closer than 1m (headphones in a flight simulator or bullets whizzing by the head), it is necessary to generate other listening zones to create effects in close proximity on either the right or left side of the head.

MacroFX is a multi-zone system designed to provide transparent flexibility to a developer wishing to create effects outside of the limitations set forth by the three DirectSound 3D distance zones. Under Macro FX, the following proximal areas are set forth:

Zone 0 - Far distance, where sound intensity is constant
Zone 1 - Distant, where sound intensity follows 1/R^n law
Zone 2 - Near-field FX algorithm, creates proportional effects to the head
Zone 3 - In the ear whisper mode for the left ear
Zone 4 - In the ear whisper mode for the right ear
Zone 5 - In the head (we suspect to simulate a migraine)

As we mentioned earlier, MacroFX is transparent to the developer, so the benefits can be heard with no extra work involved. Unfortunately, there doesn't seem to be a tremendous call for near-proximity effects. However, being that the added capability is free from performance degradation, there may indeed be a more generous use of "flies buzzing around the head" in the future.

Another step in the direction of true sound realism is a consideration of the surrounding environment. As an extension of EAX, EnvironmentFX takes into account not only direct sound, but also early reflections and reverberation of a sound source to provide a true-to-life reproduction of sound decay against a preset environment (wood, stone, carpet, etc.).

Several variables influence the way sound is reverberated back to a listener; EnvironmentFX uses these characteristics to create "sound environments" that are assigned to a locale. Room size, high frequency cutoff, density and diffusion are only a few of the aspects and the calculations are understandably involved, but access to EnvironmentFX is simplified since the technology is only as difficult to use as Creative Labs' EAX API (both EAX 1.0 and 2.0)