Environmental Audio Extensions

from Wikipedia, the free encyclopedia

Environmental Audio Extensions ( EAX ) is a proprietary system developed by Creative Labs that is used to make ambient noise in computer games appear as real as possible. Since every noise sounds different in different rooms due to reflections on the walls etc., one and the same sound would theoretically have to be recorded under different conditions in a computer game. To avoid this workload, the sound is recorded only once and the game engine tells EAX in which environment this sound should sound. EAX calculates the sound in the respective room and passes it on to the loudspeakers. In newer versions, EAX supports sound output on up to eight speakers ( 7.1 ), creating the illusion of being in the middle of the action ( surround sound ).

history

EAX 1.0 was developed by Creative in 1998 for the Sound Blaster Live! presented. This first version of EAX supported 32 voices; Developers could choose different presets that were applied to the sounds, creating the effect of different environments. With EAX 2.0 in 2000 the possibility was added to simulate the different acoustic properties of different materials. In addition, it was now possible to include the influence of objects between the noise source and the listener. With the Audigy cards came EAX Advanced HD 3.0, which supported 64 voices, enabled smooth cross-fading from one ambient effect to another, and gave developers better options for influencing the sound output. EAX Advanced HD 4.0 added the ability to simulate different environmental effects at the same time. The latest version is EAX Advanced HD 5.0 ​​and is supported by the X-Fi series (except "X-FI Xtreme"). Among many other changes, the number of votes has also been increased to 128.

The specifications of EAX 1.0 and EAX 2.0 were published by Creative, so other manufacturers of sound cards can support EAX 2.0 via software emulation . Former format competing with EAX was Aureal 3rd Dimension Technology , but after Creative's takeover of the Aureal developer company , it was no longer developed.

Windows

With Windows Vista , the playback of EAX effects is only possible to a limited extent, as the hardware abstraction layer of DirectSound is not available with DirectX 10 or DirectX 9L , via which DirectSound commands are transmitted to hardware EAX chips for calculation . Due to the lack of the DirectSound HAL for Vista, EAX effects cannot be calculated in hardware in many previous games. The few games that use the OpenAL interface instead of DirectSound are an exception .

Creative Labs therefore provides a tool called "ALchemy" (pun on "OpenAL"), which translates the DirectSound commands of many games into OpenAL commands and thus makes them fully functional under Windows Vista. According to Creative Labs, the computing power required for this translation should be low. So far, however, "ALchemy" does not support all known games by far. In the meantime, ALchemy is also available free of charge for the sound cards of the Audigy series, after initially only X-Fi cards were supported for free and later Audigy cards were supported for a fee.

See also

Web links

Commons : Environmental Audio Extensions  - collection of images, videos and audio files