| |
3D Audio
The word 3D has always been used to tell consumers that a product is cool. We see 3D games, 3D movies, and I've even seen a manufacturer label their scanners as 3D scanners! Imagine that!
So, what exactly is 3D audio? The standard stereo configuration uses one speaker on the left and one on the right. This creates a very flat (some would call it 2D) soundstage. Only sound emanating from the front is used to create the environment. It is difficult to create the illusion of sound coming from the sides or from behind.
3D audio is the ability to encircle the listener with sounds emanating from all directions. With the introduction of the Sound Blaster Live!, Creative pioneered the use of 4 speakers in the PC sound market by recommending 4-channel speakers with the SBLive!
3D Positioning
The ability to create sounds that encircle the listener is fundamental in adding another level of realism to movies. Since Star Wars, Dolby Surround has gained widespread acceptance in theaters as well as the home. Using speakers placed at both sides of the theater, movie makers can now envelop the audience with sound.
Similarly in the PC gaming world, 3D positioning in first-person games add another level of realism by allowing gamers to pinpoint exactly which direction a sound is coming from, in relation to the graphics that is appearing on-screen.
The SBLive! uses Microsoft's DirectSound3D API for 3D positioning. This allows game developers to place a sound around the listener, and set parameters like the direction of the sound from the listener, the volume of the sound, and the distance of the sound from the listener.
Up/Down Axis
The up/down axis available in the DirectSound3D was not supported by early SBLive! drivers. Thus the SBLive! could not generate sound that was specified to be above or below the listener. However, with Live!Ware 2 and above, this feature was added.
3D Streams
Due to the the additional processing required to play back and position a sound in 3D, the number of 3D sounds that can be played back by the card is limited to the power of the sound processor, in this case, the EMU10K1.
The very first SBLive! drivers could only do 8 DirectSound3D streams because research by the engineers at EMU concluded that the human ear and brain can at most recognize sounds coming from 8 different directions.
Due to the demands of the gaming community, Creative has increased the initial number of DirectSound3D streams to 32, enabling 32 sounds to be positioned individually in 3D space. So you can have 32 sounds coming from all directions. How would you differentiate that!
A3D
A3D is a proprietary API for soundcards based on the Vortex chipset. It is not available for use on other sound cards but was early in the market (before the SBLive! and EAX even existed) and gained some support from developers.
A3D 1.0 included specifications for modelling a 3D space using 2 speakers, as well as including most of the features of DirectSound3D for positioning sounds in 3D. Most developers would rather use the open standard DirectSound3D rather than a proprietary API.
A3D Compatibility
As the SBLive! was late in the market, with A3D already months ahead and rather established, Creative did a A3D 1.0 wrapper that allows games that use A3D to work with the SBLive! This feature is unadvertised.
It does this by converting the A3D calls into the equivalent DirectSound3D calls, thus allowing the SBLive! to position sounds in 3D using the A3D API.
The A3D.DLL in the WINDOWS\SYSTEM folder is the A3D wrapper. It should be 59,392 bytes.
Aureal has also released a wrapper called A2D, to allow non-A3D cards to hear the 3D sound from games that use A3D 1.0 and 2.0. This works like the wrapper and converts A3D calls to DirectSound3D supported by all 3D sound cards.
Links
|
|
| contents |
|
Overview
EMU10K1
tasks performed, upgradability through Live!Ware, open source?
Wave Audio
multi-channel, full-duplex, digital processing & mixing, locking at 48kHz.
3D Audio
positioning, up/down axis, 3D streams, A3D.
Environmental Audio
EAX 1.0, 2.0, 3.0, I3DL2, occlusion, obstructions, EAX in other sound cards.
Music & MIDI
FM & wavetable synthesis, voices, MIDI devices, MIDI channels, MIDI in/out, effects.
SoundFonts
General MIDI, GS, DLS2, DirectMusic, MPEG-4.
|
Our Sponsor:
|
|
Back To Top